Positive relationships between FOS and MDD (count: 0)
Positive relationships between FOS and other components at different levels (count: 1)
Genetic/epigenetic locus
Protein and other molecule
Cell and molecular pathway
Neural system
Cognition and behavior
Symptoms and signs
Environment
Positive relationship network of FOS in MK4MDD
Network loading ...
Note:
1. The different color of the nodes denotes the level of the nodes.
Genetic/Epigenetic Locus
Protein and Other Molecule
Cell and Molecular Pathway
Neural System
Cognition and Behavior
Symptoms and Signs
Environment
MDD
2. Besides the component related relationships from literature, gene mapped protein and protein mapped gene are also shown in the network.
If the mapped gene or protein is not from literature, square node would be used instead of Circle node.
Accordingly, the relationship is marked with dot line.
2. User can drag the nodes to rearrange the layout of the network. Click the node will enter the report page of the node.
Right-click will show also the menus to link to the report page of the node and remove the node and related edges.
Hover the node will show the level of the node and hover the edge will show the evidence/description of the edge.
3. The network is generated using Cytoscape Web
Negative relationships between FOS and MDD (count: 0)
Negative relationships between FOS and other components at different levels (count: 0)
Leishmania is an intracellular protozoan parasite of macroph......
Leishmania is an intracellular protozoan parasite of macrophages that causes visceral, mucosal, and cutaneous diseases. The parasite is transmitted to humans by sandflies, where they survive and proliferate intracellularly by deactivating the macrophage. Successful infection of Leishmania is achieved by alteration of signaling events in the host cell, leading to enhanced production of the autoinhibitory molecules like TGF-beta and decreased induction of cytokines such as IL12 for protective immunity. Nitric oxide production is also inhibited. In addition, defective expression of major histocompatibility complex (MHC) genes silences subsequent T cell activation mediated by macrophages, resulting in abnormal immune responses.More...
B cells are an important component of adaptive immunity. The......
B cells are an important component of adaptive immunity. They produce and secrete millions of different antibody molecules, each of which recognizes a different (foreign) antigen. The B cell receptor (BCR) is an integral membrane protein complex that is composed of two immunoglobulin (Ig) heavy chains, two Ig light chains and two heterodimers of Ig-alpha and Ig-beta. After BCR ligation by antigen, three main protein tyrosine kinases (PTKs) -the SRC-family kinase LYN, SYK and the TEC-family kinase BTK- are activated. Phosphatidylinositol 3-kinase (PI3K) and phospholipase C-gamma 2 (PLC-gamma 2) are important downstream effectors of BCR signalling. This signalling ultimately results in the expression of immediate early genes that further activate the expression of other genes involved in B cell proliferation, differentiation and Ig production as well as other processes.More...
Specific families of pattern recognition receptors are respo......
Specific families of pattern recognition receptors are responsible for detecting microbial pathogens and generating innate immune responses. Toll-like receptors (TLRs) are membrane-bound receptors identified as homologs of Toll in Drosophila. Mammalian TLRs are expressed on innate immune cells, such as macrophages and dendritic cells, and respond to the membrane components of Gram-positive or Gram-negative bacteria. Pathogen recognition by TLRs provokes rapid activation of innate immunity by inducing production of proinflammatory cytokines and upregulation of costimulatory molecules. TLR signaling pathways are separated into two groups: a MyD88-dependent pathway that leads to the production of proinflammatory cytokines with quick activation of NF-{kappa}B and MAPK, and a MyD88-independent pathway associated with the induction of IFN-beta and IFN-inducible genes, and maturation of dendritic cells with slow activation of NF-{kappa}B and MAPK.More...
Classically, colorectal cancer (CRC) has been believed to de......
Classically, colorectal cancer (CRC) has been believed to develop from normal mucosa through the premalignant adenoma by the step-wise accumulation of mutations. All CRC display either microsatellite instability (MSI) or chromosome instability (CIN). MSI occurs in 15% of colon cancers and results from inactivation of the DNA mismatch repair (MMR) system by either MMR gene mutations or hypermethylation of the MLH1 promoter. MSI promotes tumorigenesis through generating mutations in target genes that possess coding microsatellite repeats, such as beta-catenin, TGFBR2 and BAX. CIN is found in the majority of colon cancers and leads to a different pattern of gene alterations that contribute to tumor formation. Genes involved in CIN are those coding for APC, K-ras, SMAD4 and p53.More...
The mitogen-activated protein kinase (MAPK) cascade is a hig......
The mitogen-activated protein kinase (MAPK) cascade is a highly conserved module that is involved in various cellular functions, including cell proliferation, differentiation and migration. Mammals express at least four distinctly regulated groups of MAPKs, extracellular signal-related kinases (ERK)-1/2, Jun amino-terminal kinases (JNK1/2/3), p38 proteins (p38alpha/beta/gamma/delta) and ERK5, that are activated by specific MAPKKs: MEK1/2 for ERK1/2, MKK3/6 for the p38, MKK4/7 (JNKK1/2) for the JNKs, and MEK5 for ERK5. Each MAPKK, however, can be activated by more than one MAPKKK, increasing the complexity and diversity of MAPK signalling. Presumably each MAPKKK confers responsiveness to distinct stimuli. For example, activation of ERK1/2 by growth factors depends on the MAPKKK c-Raf, but other MAPKKKs may activate ERK1/2 in response to pro-inflammatory stimuli.More...
Activation of T lymphocytes is a key event for an efficient ......
Activation of T lymphocytes is a key event for an efficient response of the immune system. It requires the involvement of the T-cell receptor (TCR) as well as costimulatory molecules such as CD28. Engagement of these receptors through the interaction with a foreign antigen associated with major histocompatibility complex molecules and CD28 counter-receptors B7.1/B7.2, respectively, results in a series of signaling cascades. These cascades comprise an array of protein-tyrosine kinases, phosphatases, GTP-binding proteins and adaptor proteins that regulate generic and specialised functions, leading to T-cell proliferation, cytokine production and differentiation into effector cells.More...
The T Cell Receptor plays a key role in the immune system. T......
The T Cell Receptor plays a key role in the immune system. The specificity of the receptor is governed by the binding site formed from the mature alpha and beta chains (shown here) or gamma and delta chains in gamma/delta T Cells. It is the ability of this receptor to bind a complex of foreign peptide in the groove of an MHC molecule that leads to T cell activation. Upon activation the T cell can assist in activating other cells or carry out cytolytic attacks depending on the particular T cell type. The CD3 complex and CD4 (Th cells) or CD8 (Tc cells) work to transmit the activation signal to the T cell's transcriptional machinary upon engagement of the receptor.More...
Physical interactions between intergrin alpha4beta1 heterodi......
Physical interactions between intergrin alpha4beta1 heterodimer expressed on B cells and counter receptors on stroma cells are key mediators of the survival of normal and malignant B cells. Recent data indicate that integrin stimulation increases FBI-1, XIAP, surviving, and CCT4 expression but inhibits Requiem, c-Fos, and caspase 3 and 7 induction.More...
Repression of Pain Sensation by the Transcriptional Regulator DREAM
The molecular events that lead to the perception of pain are......
The molecular events that lead to the perception of pain are a key research field in medicine and drug discovery. The opioid receptors modulate pain signaling in response to endogenous peptide ligands and opiate drugs such as morphine. The kappa opioid receptor plays a key role in the profound analgesia of opiates and is activated by the endogenous peptide ligand dynorphin, encoded by the prodynorphin gene. Production of prodynorphin is transcriptionally regulated by a downstream regulatory element (DRE) in the prodynorphin gene. A transcription factor called DREAM (DRE antagonistic modulator) binds to the DRE and represses prodynorphin transcription when bound. DREAM binds calcium with 4 EF-hand motifs and the binding of DREAM to DNA is repressed in the presence of calcium. Many transcription factors are regulated by calcium indirectly through calcium sensitive kinases and phosphatases, but DREAM is unique to date in being a transcription factor that directly binds calcium and is regulated by calcium binding. DREAM may also regulate other genes such as c-fos. DREAM is expressed in spinal cord neurons in regions involved in pain signaling. The regulation of prodynorphin expression by DREAM also leads to the hypothesis that DREAM is involved in pain signaling. Transgenic mice lacking the DREAM gene were unusually pain insensitive and had elevated spinal levels of dynorphin and tonic activation of the kappa opioid receptor, supporting this hypothesis. Other functions of DREAM may exist such as regulation of presenilins and potassium channel activity in the heart. DREAM is also known as calsenilin and KChIP3 through its association with these other proteins. These processes were not affected in mice lacking the DREAM gene however.More...
Interleukin-6 (IL-6) is a cytokine that provokes a broad ran......
Interleukin-6 (IL-6) is a cytokine that provokes a broad range of cellular and physiological responses. In addition to playing a role in inflammation and hematopoiesis, IL-6 is involved in other processes such as neuronal differentiation and bone loss. To produce these effects IL-6 signals through a receptor composed of two different subunits, an alpha subunit that produces ligand specificity and gp130, a receptor subunit shared in common with other cytokines in the IL-6 family. Binding of IL-6 to its receptor initiates cellular events including activation of JAK kinases and activation of ras-mediated signaling. Activated JAK kinases phosphorylate and activate STAT transcription factors, particularly STAT3, that move into the nucleus to activate transcription of genes containing STAT3 response elements. The ras-mediated pathway, acting through Shc, Grb-2 and Sos-1 upstream and activating Map kinases downstream, activates transcription factors such as ELK-1 and NF-IL-6 (C/EBP-beta) that can act through their own cognate response elements in the genome. These factors and other transcription factors like AP-1 and SRF (serum response factor) that respond to many different signaling pathways come together to regulate a variety of complex promoters and enhancers that respond to IL-6 and other signaling factors.More...
Bone density and structure is maintained through a balance o......
Bone density and structure is maintained through a balance of bone resorption by osteoclasts and bone deposition by osteoblasts. The combination of simultaneous resorption and deposition creates continual remodeling of bone while excess osteoclast activity leads to an imbalance and a loss of bone density, causing osteoporosis. RANK (receptor activator of NF-kB ligand) is a receptor in the TNF receptor gene family that is involved in osteoclast differentiation. RANK-ligand, also called osteoprotegerin-ligand, binds to RANK, induces receptor dimerization, and activates downstream signaling. Osteoprotegerin is a decoy receptor for RANK-ligand that suppresses osteoclast activity and bone remodeling, helping to maintain balanced bone remodeling. RANK-ligand and osteoprotegerin are produced by osteoblasts and some factors regulate osteoclast activity indirectly through their action on the expression of these factors by osteoblasts. Binding of RANK-ligand to RANK activates signaling through TRAF-6. TRAF-6 induces several downstream signaling events, including activation of NF-kB, c-Fos and the kinase JNK1. Jnk-1 activation contribute to fos activation by RANK-ligand and may be involved in the modulation of RANK-ligand by other factors such as estrogen. Mice lacking the c-Fos gene have overly dense bone and decreased bone resorption due to reduced osteoclast differentiation, indicating that c-Fos is an important mediator of osteoclast differentiation. One of the results of c-Fos induction is transcriptional activation of interferon-beta. Interferon-beta binds to its receptor on neighboring osteoclast precursor cells to block RANK-ligand signaling and down-regulate c-Fos expression, inhibiting further osteoclast differentiation. Mice lacking interferon-beta or the interferon-beta receptor lose bone due to uncontrolled osteoclast activity, demonstrating the importance of this mechanism in vivo. Interferon-beta signaling could be used as a mechanism to prevent osteoporosis and other conditions involving excessive osteoclast resorption of bone.More...
Nerve growth factor (NGF) is one of a family of neurotrophin......
Nerve growth factor (NGF) is one of a family of neurotrophins that induce the survival and proliferation of neurons. In cell culture NGF induces the formation of neurite projections and in vivo may stimulate the innervation of tissues. NGF plays a role in the repair, regeneration, and protection of neurons, and as such could serve as a therapeutic agent in neurodegenerative conditions such as Alzheimer's disease. One potential method of NGF application would be through gene therapy or through implantation of cells that have been genetically modified ex vivo. NGF has also been suggested to play a role in other physiological systems and tissues such as the immune system. NGF has two receptors, TrkA and the p75(NTR). NGF may signal its neuroprotective actions through the tyrosine kinase TrkA receptor and trigger apoptosis in some cells through the p75 receptor. High-affinity binding of NGF requires both TrkA and p75(NTR). Binding of NGF to the TrkA receptor causes activation of the receptor tyrosine kinase and downstream signaling cascades. One of the downstream signaling pathways of NGF activates phospholipase C, releasing DAG and IP3 and activating associated downstream pathways such as protein kinase C. Another NGF-activated pathway is the ras-mediated activation of the map kinase pathway. This pathway is initiated through recruitment and activation of Shc, which leads to ras activation through Grb-2 and Sos-1. The Map kinase cascade includes raf, Mek and Erk. The downstream effectors of the ras pathway include activation of fos and jun to form AP-1, activating genes through this transcription factor. Other transcription factors involved in NGF responses include Egr and CREB. The Egr family of transcription factors as well as the Mek/Erk pathway contribute to NGF-induced neurite formation. The CREB family of transcription factors are involved in NGF-induced survival of sympathetic neurons. Further understanding of NGF signaling may be applied to the modulation of NGF responses in neurodegenerative conditions.More...
Platelet Derived Growth Factor (PDGF) plays a critical role ......
Platelet Derived Growth Factor (PDGF) plays a critical role in cellular proliferation and development. The biologically active form is a dimer formed from the A and B chains. PDGF is active to a differing degree depending on which dimer is formed (AA, AB, or BB). The PDGF Receptor (PDGFR) is also a dimer and can form from the combination of the alpha and beta chains in any order (alpha-alpha, alpha-beta, beta-beta). The PDGFR dimer is only formed after ligand binding so the alpha/beta composition of the receptor can be influenced by the form of PDGF that is present. Upon binding of ligand the PDGFR is tyrosine phosphorylated and leads to the phosphorylation of several other cellular proteins.More...
Cadmium induces DNA synthesis and proliferation in macrophages
Exposure to divalent cadmium ions (Cd2+) is a known cancer r......
Exposure to divalent cadmium ions (Cd2+) is a known cancer risk factor, but the molecular mechanisms responsible for the inappropriate induction of cellular proliferation by cadmium are still being figured out. One cellular model used to study this process is macrophages grown in culture. In cultured macrophages, cadmium acts both at the cell surface and in the cytoplasm to induce proliferation. At the cell surface, cadmium interacts with a pertussis-sensitive cell surface receptor, probably a Gi-coupled GPCR, to stimulate proliferation. Cadmium can enter cells through calcium ion channels and once in cells affects calcium release by the ER. In addition to changes in intracellular calcium, the proliferative effects of cadmium are mediated by the Ras/Map kinase pathway, and also NF-kB. Inhibition of phospholipase C, map kinases, or NF-kB with a variety of pharmacological inhibitors all blocked the activation of cellular proliferation by cadmium. Protein kinase C is also activated by cadmium, upstream of the Map kinase pathway. Changes in transcription induced by cadmium include induction of immediate early genes like fos, jun, and myc. In addition to inducing cellular proliferation, cadmium also is slightly genotoxic due to inhibition of DNA repair, activates stress genes, and inhibits the immune system. The immuno-modulatory effects observed with cadmium treatment may also involvement transcriptional disregulation, including the expression of cytokines such as IL-4, IL-10, and TNF-alpha. Although macrophages have been used for many studies, other cell types are also the target of cadmiums toxicity.More...
Significant progress has been made towards delineation of th......
Significant progress has been made towards delineation of the intrinsic molecular processes that regulate B lymphocyte immune function. Recent observations have provided a clearer picture of the interactive signaling pathways that emanate from the mature B cell antigen receptor (BCR) complex and the different precursor complexes that are expressed during development. Studies have also revealed that the net functional response to a given antigenic challenge is affected by the combined action of BCR-dependent signaling pathways, as well as those originating from various coreceptors expressed by B cells (e.g. CD19, CD22, FcgRIIb and PIR-B). It is now well established that reversible tyrosine phosphorylation plays an important role in regulating B cell biology. In particular, binding of antigen to the BCR promotes the activation of several protein tyrosine kinases (PTK) that, in conjunction with protein tyrosine phosphatases (PTP), alter the homeostasis of reversible tyrosine phosphorylation in the resting B cell. The net effect is a transient increase in protein tyrosine phosphorylation that facilitates the phosphotyrosine dependent formation of effector protein complexes, promotes targeting of effector proteins to specific microenvironments within the B cell and initiates the catalytic activation of downstream effector proteins. Studies have demonstrated that Src family PTKs are activated initially and serve to phosphorylate CD79a and CD79b thereby creating phosphotyrosine motifs that recruit downstream signaling proteins. In particular, phosphorylation of the BCR complex leads to the recruitment and activation of the PTK Syk, which in turn promotes phosphorylation of PLCg, Shc and Vav. Additionally, the Tec family member Btk is recruited to the plasma membrane where it is involved in activation of PLCg. Initiation of B lymphocyte activation is dependent on the tyrosine phosphorylation-dependent formation of multi-molecular effector protein complexes that activate downstream signaling pathways. The formation of such complexes was initially hypothesized to occur primarily via effector protein binding to the BCR complex itself. However, recent studies have demonstrated that productive signaling via the BCR is in fact dependent on tyrosine phosphorylation of one or more adapter proteins that play a crucial role in recruitment and organization of effector proteins at the plasma membrane. The SLP-65/BLNK adapter protein has recently been shown to play a crucial role in recruitment and activation of key signal transducing effector proteins in the B cell. After the BCR has been engaged by antigen and the activation response has been initiated, numerous second messengers and intermediate signal transducing proteins are activated. These include the production of lipid second messengers by phosphatidylinositol 3-kinase, and the PLC-dependent hydrolysis of phosphatidylinositol 4,5-bisphosphate to yield diacylglycerol and 1,4,5-inositoltrisphosphate (IP3). DAG is important for activation of PKC whereas IP3 promote release of calcium from the endoplasmic reticulum and the subsequent influx Ca2+ from the extracellular space. Numerous intermediate signaling proteins are also activated including the Ras and Rap1, which are small molecular weight GTPases and these ultimately lead to the activation of MAP kinases including Erk, JNK and p38. The net effect of second messenger production and activation of intermediate signaling proteins is the concerted regulation of several transcription factors that mediate gene transcription in the B cell.More...
The IL-2 receptor is a key component of immune signaling and......
The IL-2 receptor is a key component of immune signaling and is required for the activation, proliferation, and survival of T cells. This receptor is composed of three polypeptide chains, the alpha, beta and gamma chains. The IL-2 receptor gamma chain is a common component for several other cytokine receptors, including IL-4, IL-7, IL-9 and IL-15. The IL-2 receptor beta chain is essential for IL-2 signaling and is also a component of the IL-15 receptor complex. The polypeptides of the IL-2 receptor do not themselves have intrinsic catalytic activity, but interact with cytoplasmic signaling proteins to transduce signals. br>Different regions of the cytoplasmic domain of the IL-2 receptor beta chain interact and couple with distinct signaling pathways and cellular responses. JAK1 associates with the beta chain, and JAK3 with the gamma chain. Binding of IL-2 induces heterodimerization of receptor subunits, and activation of JAK kinase activity. Tyrosine residues in the beta chain cytoplasmic domain are phosphorylated during activation, recruiting other factors to the phosphorylated tyrosine residues through src homology 2 (SH2) domains. The adaptor protein Shc binds to phosphorylated tyrosine 338 of the beta chain. When bound, Shc is phosphorylated and couples through Grb2 and Sos-1 to activate Ras and stimulate T cell proliferation. Another key proliferative pathway activated by IL-2 is phosphorylation of STAT-5 by JAK kinases. STAT-5 is recruited to IL-2 beta phosphorylated tyrosines at multiple positions, including Y338, Y392 and Y510. Once phosphorylated, STAT-5 enters the nucleus to regulate the transcription of several genes, some proliferative such as cyclin genes and others that are involved in T cell immune function such as cytokine genes. The suppressors of cytokine activation, SOCS-3 and SOCS-1, oppose phosphorylation and activation of STAT-5 and JAK1 caused by IL-2. PI3 kinase is another protein recruited to IL-2 receptor beta chain tyrosines when phosphorylated. Activation of PI3 Kinase also contributes to the proliferative activity of IL-2 in T cells. The role of other tyrosines in the IL-2 receptor beta chain, Y355, Y358 and Y361, is not yet clear, but may be involved in signaling by the protein kinase p56lck. In addition to stimulating T cell activation and proliferation, IL-2 activation blocks T cell apoptosis through multiple pathways. Among the genes activated by STAT-5 are BCL-xL, an inhibitor of apoptosis, and fas-ligand, an activator of apoptosis in cells expressed the fas receptor. PI3 kinase also contributes to anti-apoptotic activity of IL-2 through AKT activation. T cell responses to IL-2 must be coordinated in part in the complex protein-protein interactions with the IL-2 receptor beta chain.More...
Insulin like growth factor 1 (IGF-1) and its receptor (IGF-1......
Insulin like growth factor 1 (IGF-1) and its receptor (IGF-1R) provide a potent proliferative signaling system that stimulates growth in many different cell types and blocks apoptosis. In vivo IGF-1 acts as an intermediate of many growth hormone responses, and may stimulate the growth of some types of cancer. IGF-1 also provides a mitogenic signal to act as a growth factor for many tissue culture cells. One component of IGF-1 mitogenic signaling is association of the receptor tyrosine kinase with Shc, Grb2, and Sos-1 to activate ras and the Map kinase cascade (raf, Mek, Erk). An endpoint of the Map kinase pathway is modification of transcription factor activity, such as activation of ELK transcription factors. Serum response factor (SRF) and AP-1 contribute to mitogenic signaling by many factors. Phosphorylation of IRS-1 and PI3 kinase activation are also involved in IGF-1 signaling, similar to insulin signaling.More...
The ever evolving mitogen-activated protein kinase (MAP kina......
The ever evolving mitogen-activated protein kinase (MAP kinase) pathways consist of four major groupings and numerous related proteins which constitute interrelated signal transduction cascades activated by stimuli such as growth factors, stress, cytokines and inflammation. The four major groupings are the Erk (red), JNK or SAPK (blue), p38 (green) and the Big MAPK or ERK5 (light blue) cascades. Signals from cell surface receptors such as GPCRs and growth factor receptors are transduced, directly or via small G proteins such as ras and rac, to multiple tiers of protein kinases that amplify these signals and/or regulate each other. The diagram is organized to illustrate the cascades by the background colors and also the tiers of kinases as indicated down the left hand side and separated by the horizontal dashed lines. In some cascades the first activation tier involves the MAPKKKKs, MAP kinase kinase kinase kinases or MAP4K proteins. The next tier are the serine/threonine MAPKKKs, MAP kinase kinase kinase or MAP3Ks such as RAF, TAK, ASK, and MEKK1. This level has the greatest amount of cross-communication curently known. The serine/threonine/tyrosine MAPKKs, MAP Kinase kinases or MAP2Ks, such as the MKK and MEK kinases, are one step up from the MAP kinase cascade, phosphorylating and activating these kinases. The focal tier, the MAPKs or MAP kinases includes JNK1, p38, and ERKs, and are the kinases that give each cascade its name BR>The endpoints of these cascades, shown in the bottom tier, includes the MAPK activated protein kinases (MAPKAPK) and some of the numerous transcription factors that regulate genes involved in apoptosis, inflammation, cell growth and differentiation NOTES:- The shared color and the bold arrows show the major flow of each cascade. - The smaller arrows indicate cross communication between cascades. In many cases this is restricted to certain cell types or requires additional factors. - Kinases that have been identified as MAP kinases based on sequence or structural homolgies but have not yet been assigned to a cascade have been placed out side the grouping backrgounds. - The PAKs (p21 associated kinases) are not MAPKs but participate in the transduction to the JNK cascade are included for this reason.) - MEK4 appears to function in both the JNK and p38 cascades and so has a mixed color. MEK4 signal is much stronger in the JNK than the p38 cascade and so the bold arrow towards the JNK and the dashed arrow towards the p38 cascade indicate the relative strengths of signaling. - For space and readability concerns not all interactions and stimuli are indicated and the scaffold and phosphatase proteins are not shown.More...
The appropriate signaling through the insulin pathway is cri......
The appropriate signaling through the insulin pathway is critical for the regulation of glucose levels and the avoidance of diabetes. Insulin forms a complex with the Insulin Receptor (IR) and b chains to form the active signaling complex. Through recruitment of adaptor molecules and the activation of RAS, the activated IR can cause transcriptional activation.More...
Thrombopoietin (TPO) binds to its receptor inducing aggregat......
Thrombopoietin (TPO) binds to its receptor inducing aggregation and activation. TPO signals its growth regulating effects to the cell through several major pathways including MAPK (ERK and JNK), Protein Kinase C, and JAK/Stat.More...
G-aS-coupled receptors stimulate adenylyl cyclase (AC), whic......
G-aS-coupled receptors stimulate adenylyl cyclase (AC), which synthesizes cAMP from ATP. In contrast Gai-coupled receptors inhibit AC and so reduce cAMP formation. The bg subunits from Gai and other G proteins are able to activate the MAP kinase pathways and PLCb. GPCRs coupled to the Gaq family of G proteins stimulate PLCb, which cleaves membrane phospholipids to produce IP3, which mobilizes intracellular calcium, and DAG, which activates PKC. Second messenger pathways then activate a range of effector systems to change cell behaviour; in many cases this includes the regulation of gene transcription. Dotted line shows a more indirect pathway.More...
Pertussis toxin-insensitive CCR5 Signaling in Macrophage
The chemokine receptors CCR5 and CXCR4 in macrophages are ac......
The chemokine receptors CCR5 and CXCR4 in macrophages are activated by their peptide ligands and also by the HIV envelope protein GP120 during HIV infection. One mechanism of signaling by these GPCRs is through activation of Gi signaling. These chemokine receptors can also signal through a Gi-independent pertussis toxin-insensitive pathway. This pathway elevates calcium influx into the cell through CRAC channels, ion channels that are activated by calcium release. Elevated calcium from CRAC is required for downstream activation of Pyk2, a focal adhesion-associated protein kinase. Non Gi signaling by these chemokine receptors also involves the Jnk and p38 Map kinase pathways leading to AP-1 activation and activation of genes such as MIP-1 and MCP-1. This pathway may be involved in the role of macrophages in the pathogenesis of AIDS.More...
The epidermal growth factor (EGF) peptide induces cellular p......
The epidermal growth factor (EGF) peptide induces cellular proliferation through the EGF receptor, which has a tyrosine kinase cytoplasmic domain, a single transmembrane domain and an extracellular domain involved in EGF binding and receptor dimerization. Inhibitors of the EGF receptor are being pursued as potential cancer therapies and EGF may stimulate wound healing. Mutation of the EGF receptor has been associated with cancer in humans. The proliferative effects of EGF are signaled through several pathways. Binding of EGF results in EGF receptor dimerization, autophosphorylation of the receptor, and tyrosine phosphorylation of other proteins. The EGF receptor activates ras and the MAP kinase pathway, ultimately causing phosphorylation of transcription factors such as c-Fos to create AP-1 and ELK-1 that contribute to proliferation. Activation of STAT-1 and STAT-3 transcription factors by JAK kinases in response to EGF contributes to proliferative signaling. Phosphatidylinositol signaling and calcium release induced by EGF activate protein kinase C, another component of EGF signaling. Crosstalk of EGF signaling with other pathways make the EGF receptor a junction point between signaling systems.More...
The innate immune response responds in a general manner to f......
The innate immune response responds in a general manner to factors present in invading pathogens. Bacterial factors such as lipopolysaccharides (LPS, endotoxin), bacterial lipoproteins, peptidoglycans and also CpG nucleic acids activate innate immunity as well as stimulating the antigen-specific immune response and triggering the inflammatory response. Members of the toll-like receptor (TLR) gene family convey signals stimulated by these factors, activating signal transduction pathways that result in transcriptional regulation and stimulate immune function. TLR2 is activated by bacterial lipoproteins, TLR4 is activated by LPS, and TLR9 is activated by CpG DNA; peptidoglycan recognition protein (PGRP) is activated by peptidoglycan (PGN). The downstream signaling pathways used by these receptors are similar to that used by the IL-1 receptor, activating the IL-1 receptor associated kinase (IRAK) through the MyD88 adaptor protein, and signaling through TRAF-6 and protein kinase cascades to activate NF-kB and Jun. NF-kB and c-Jun activate transcription of genes such as the proinflammatory cytokines IL-1 and IL-12. Several recent reports have suggested that the functional outcomes of signaling via TLR2, TLR4 and PGRP are not equivalent. For example, while the LPS-induced, p38-dependent response was dependent upon PU.1 binding, the PGN-induced, p38 response was not. The intracelular receptor for PGN, PGRP is conserved from insects to mammals. In insects, PGRP activates prophenoloxidase cascade, a part of the insect antimicrobial defense system. Because mammals do not have the prophenoloxidase cascade, its function in mammals is unknown. However, it was suggested that an identical protein Tag7 was a tumor necrosis factor-like (TNF-like) cytokine. PGRP/Tag7 possesses cytotoxicity and triggers intranucleosomal DNA fragmentation in target cells in the same way as many known members of the TNF family. Fragmentation of DNA is one of the characteristics of apoptosis. The possibility that in another system, PGRP/Tag7 would induce NF-kB activation, as observed for TRAIL (TNF-related apoptosis-inducing ligand) receptors canot be ruled out.More...
Interleukin-3 promotes the proliferation and differentiation......
Interleukin-3 promotes the proliferation and differentiation of hematopoietic cells through binding to its receptor. The receptor for IL-3 is a heterodimer with a ligand-specific alpha chain (70 kD, CD123) and a common beta chain (shared with IL-5 and GM-CSF). Signaling is believed to be primarily through Stat5 and the MAPK pathways.More...
Reactive oxygen species (ROS) can damage biological macromol......
Reactive oxygen species (ROS) can damage biological macromolecules and are detrimental to cellular health. Electrophilic compounds, xenobiotics and antioxidants are sources of reactive oxygen species, creating oxidative stress that can harm cells. Enzymes are involved in the Phase II detoxification of xenobiotics to reduce cellular stress include glutathione transferases, quinone reductase, epoxide hydrolase, heme oxygenase, UDP-glucuronosyl transferases, and gamma-glutamylcysteine synthetase. Expression of these genes protects cells from oxidative damage and can prevent mutagenesis and cancer. Transcription of these enzymes is coordinately regulated through antioxidant response elements (AREs). Nrf2 (NF-E2-related factor 2) and Nrf1 are transcription factors that bind to AREs and activate these genes. Inactive Nrf2 is retained in the cytosol by association a complex with the cytoskeletal protein Keap1. Cytosolic Nrf2 is phosphorylated and translocates into the nucleus in response to protein kinase C activation and Map kinase pathways. In the nucleus, Nrf2 activate genes through AREs by interacting with transcription factors in the bZIP family, including CREB, ATF4 and fos or jun. Nrf2 activation of genes is opposed by small maf proteins, including MafG and MafK, maintaining a counterbalance to Nrf2 and balancing the oxidation level of the intracellular environment.More...
The epidermis, which provides a protective barrier that unde......
The epidermis, which provides a protective barrier that undergoes a constant renewal, is a multi-layered tissue with the proliferating cells located in the basal layer. As cells leave the basal layer the underog significant differentiation, biochemical and morphological remodeling. The final differentiation results in the formation of corneocytes. In vitro keratinocytes mimic this process. Several genes mark keratinocyte specific differentiation. Among the most frequently tracked markers are Transglutaminase, Cystatin and Involucrin. The keratinocyte differentiation studies have identified and provided significant detail regarding the involvement of three of the 4 major MAP kinase pathways from several diverse stimuli such as EGF, FAS, TNF and Calicium influx. The p38 cascade is represented twice since both p38alpha (p38) and p38delta (MAPK13) are involved. The keratinocyte differentiation cascased also provide for detailed study of the functions of individual PKC isoforms. It is interesting to note the contrasting functions of the PKC isoforms in this process. In recent studies it has been determined that the cPKC (conventional/classical Protein Kinase C) isoforms, which are calcium-, phospholipid-, and diacylglycerol-dependent are inhibitory where as the nPKC (novel Protein Kinase C) isoforms which are calcium independent are stimulatory for keratinocyte differentiation markers. On the right hand side is an earlier step showing the upregulation loop of TRAF2. This step occurs prior to the activation os ASK1 and the p38 cascade.More...
Erythropoietin functions to increase the number of red blood......
Erythropoietin functions to increase the number of red blood cells. Thus, it has found utility as a drug for those needing to replenish erythrocytes for a number of reasons. The signaling mechanism includes multimerization of the receptor upon ligand binding, activation of MAPK cascade, and phosphorylation and activation of Stat5.More...
The hepatocyte growth factor receptor, also called c-Met, is......
The hepatocyte growth factor receptor, also called c-Met, is activated by HGF and stimulates proliferation of hepatocytes and other cell types. Mutated forms of the HGF receptor are associated with oncogenesis and metastasis, making the HGF receptor a potential therapeutic target for cancer drugs. Changes in cell motility, cell shape, adhesion, resistance to apoptosis, and anchorage independent growth all contribute to the role of c-Met in cancer. The HGF receptor is a heterodimer with tyrosine kinase activity and associates with a multiprotein complex involved in downstream signal transduction. The HGF receptor can associate with several different signaling systems, including src, Grb2/SOS, PI3 kinase and Gab1. One of the major substrates of the activated HGF receptor tyrosine kinase is the adaptor protein Gab1. Gab1 interacts with Crk and CrkL, two proteins with SH2 and SH3 protein interaction domains that couple to signaling further downstream. The actions of HGF on paxillin, DOCK180 and Rap1 mediated through GAB1 and other members of this complex alter cell motility. Regulation of Rho, Rac1 and CDC42 pathways in response to HGF all contribute to changes in cellular motility. Another target of the HGF receptor kinase is the focal adhesion kinase, FAK. The activation of FAK induces the formation of focal adhesions, a preliminary step to increased cell motility and tissue invasion by transformed cells, and paxillin phosphorylation may also alter cell adhesion of Met transformed cells. Src and p130cas are required for the role of FAK in HGF induced cellular transformation. HGF also blocks anoikis, the induction of apoptosis through suspension of cells, by acting on Erk and AKT kinases. This activity may contribute to anchorage independent growth of Met transformed cells. Signaling by integrins also plays a key role in the activation of tissue invasive growth by HGF. The alpha6beta4 integrin acts as a cofactor along with Meta to participate in cell growth and proliferation. In addition to altering cell adhesion, proliferation and cell motility, HGF alters cellular transcription through activation of STAT3. STAT3 activation by HGF is independent of PI3 kinase or map kinases and alters gene expression leading to changes in cellular shape. Although HGF is associated with cellular proliferation and survival, in rat liver epithelial cells HGF induces apoptosis and inhibits cell growth.More...
The Fc Epsilon Receptor 1 signaling pathway in mast cells us......
The Fc Epsilon Receptor 1 signaling pathway in mast cells uses multiple core signal path to achieve its necessary ends. Through the BTK protein and PKC Mast cells are able to degranulate, through the PKC and MAPK paths the cells are able to alter cytokine expression and arachidonic acid release.More...
Role of EGF Receptor Transactivation by GPCRs in Cardiac Hypertrophy
One of responses to increased blood pressure is cardiac hype......
One of responses to increased blood pressure is cardiac hypertrophy through increased size of ventricular myocardial cells leading to increased thickness of the ventricular walls. Cardiac hypertrophy allows the heart to handle the increased stress caused by elevated blood pressure but is also a risk factor associated with heart disease. Cardiac hypertrophy results from cross-talk between G-protein coupled receptor signaling and the EGF receptor pathway. Several GPCR ligands are known to stimulate cardiac hypertrophy, including factors that regulate blood pressure such as angiotensin II and endothelin- 1. These factors stimulate phospholipase C through Gq activation, and the production of 1P3 and diacylglycerol second messengers. PKC-delta is activated by DAG and interacts with the metalloproteinase ADAM12. ADAM12 cleaves the membrane-bound HB-EGF to release soluble EGF ligand that activates EGF receptor in myocardial cells. EGF receptor activation downstream through small G proteins and the MAP kinase pathway ultimately leads to cardiac hypertrophy. Signals by GPCR ligands such as angiotensin II result in transcriptional translation of immediate early genes like fos and other genes involved in long-term remodeling of heart tissue and the physiological response to stress in the heart such as the atrial natriuretic factor. Factors such as the AKT kinase, reactive oxygen species (ROS) and NE-kB also are involved in signaling that leads to hypertrophy, although their role is not yet clear. Blocking this pathway at various steps may prevent heart disease through the prevention of cardiac hypertrophy, but may also have other consequences.More...
Interleukin 2 (IL-2) is a potent cytokine that can lead to c......
Interleukin 2 (IL-2) is a potent cytokine that can lead to cellular activation and proliferation. IL-2 Receptors are found on activated B-Cells, LPS treated Monocytes, and many T cells. The receptor is formed from three chains alpha (CD25), beta (CD122), and gamma (CD132). Primary signaling is through the JAK/Stat pathway and MAPKs.More...
Terminal differentiation of cells is often accompanied by re......
Terminal differentiation of cells is often accompanied by repression of cellular proliferation, suggesting that there is a mechanism by which these cellular functions are coordinated. Macrophage differentiation is one model system in which this occurs; as macrophages differentiate, they also stop proliferating. Transcriptional regulation plays a key role in cell cycle progression as well as many differentiation processes. Ras stimulates cell cycle progression in part through Ets transcription factors that bind to cell cycle regulatory genes to activate their expression. Ets transcription factors also help to induce early macrophage differentiation. The activation of Ras signaling by M-CSF activates transcription of genes involved in differentiation through the coordinate expression of both Ets factors and AP-1. Other genes involved in cell cycle regulation involved the coordinate action of E2F-1 and Ets transcription factors. Mets is a factor related in sequence to Ets2 that is upregulated during macrophage differentiation. Increased expression of the Mets protein during macrophage differentiation allows the creation of heterodimers with DP103 to act as transcriptional repressors of cell cycle progression genes, recruiting corepressor to promoters they interact with. DP103 is a gene previously identified as an RNA helicase involved in RNA processing that interacts with EBNA factors from Epstein Barr Virus. The transcriptional repression involving Mets with DP103 is selective, and does not involve all Ets regulated genes. While cell cycle genes are repressed by Mets, other gene activated by Ets factors such as those involved in differentiation are not repressed by Mets. The transcriptional repression by Mets also involved members of the Rb family of tumor suppressors, such as p107 and p130. This requirement for additional factors involved in regulating proliferation may allow for another level of control on cell proliferation and coordination with differentiation.More...
The drug Gleevec (also known as imatinib mesylate or STI-571......
The drug Gleevec (also known as imatinib mesylate or STI-571) was approved by the FDA in 2001 for the treatment of CML, chronic myeloid leukemia. While traditional cytotoxic cancer treatments such as chemotherapy or radiation therapy kill all dividing cells, Gleevec acts on a molecular target by a mechanism that is more specific to cancer cells. Traditional cytotoxic cancer agents have serious side effects such as nausea, weight loss, hair loss and severe fatigue that result from their lack of specificity in killing cells. Gleevec was designed as an inhibitor of a specific receptor associated with CML, and so produces less severe side effects than other cancer agents. CML is associated in most cases with a specific chromosomal defect, a translocation between chromosomes 9 and 22 that creates the Philadelphia chromosome. This translocation occurs at the site in the genome of a protein tyrosine kinase called abl, creating the abnormal bcr-abl protein, a fusion of the abl gene with another gene called bcr. The kinase activity of abl in the bcr-abl fusion is activated and unregulated, driving the uncontrolled cell growth observed in CML. White blood cells containing the bcr-abl mutation become able to proliferate in the absence of growth factors they normally require. Gleevec inhibits abl kinase activity, helping to reverse uncontrolled cell growth. Gleevec also inhibits the PDGF tyrosine kinase and the c-kit tyrosine kinase. There are a variety of cellular substrates of the bcr-abl kinase that may be involved in cellular transformation. Bcr-abl is associated with the cytoplasm as part of a large signaling complex. Some of the downstream factors in bcr-abl signaling include PI3 kinase/AKT and STAT transcription factors. The activation of bcr-abl also represses apoptosis through induction of anti-apoptosis factors such as Bad, allowing transformed cells to divide. JAK2 kinase activity appears to be one target of bcr-abl. Grb-2 phosphorylation by bcr-abl may play a role in down-regulation of tyrosine kinase signaling. STAT5 may be involved in the failure of apoptosis in bcr-abl cells. In addition to supporting the idea that cancer therapies targeting specific molecular targets should be efficacious with fewer side effects, Gleevec has also demonstrated that drugs inhibiting protein kinases can be developed successfully. Tyrosine kinases are important in a range of cellular processes, including other cancers, and will provide additional drug targets. Gleevec itself has already demonstrated potential in other cancers such as gastrointestinal stromal tumor that do not respond to existing treatments. Although Gleevec has produced very strong clinical responses in patients with early stage CML, patients with late stage disease have had an initial response followed by a relapse of drug resistant CML cells. Cancer cells in patients with Gleevec resistant cancer either had amplification of the bcr-abl gene, or mutation of a key amino acid involved in binding drug from threonine to isoleucine.More...
In human, ten members of the Toll-like receptor (TLR) family......
In human, ten members of the Toll-like receptor (TLR) family (TLR1-TLR10) have been identified (TLR11 has been found in mouse, but not in human). All TLRs have a similar Toll/IL-1 receptor (TIR) domain in their cytoplasmic region and an Ig-like domain in the extracellular region, where each is enriched with a varying number of leucine-rich repeats (LRRs). Each TLR can recognize specific microbial pathogen components. The binding pathogens component of the TLRs initializes signaling pathways that lead to induction of Interferon alpha/beta. There are three main signaling pathways: the first is a MyD88-dependent pathway that is common to all TLRs, except TLR3; the second is a TRAM-dependent pathway that is peculiar to TLR3 and TLR4 and is mediated by TRIF and RIP1; and the third is a TRAF6-mediated pathway peculiar to TLR3.More...
Activator protein-1 (AP-1) is a collective term referring to......
Activator protein-1 (AP-1) is a collective term referring to a group of transcription factors that bind to promoters of target genes in a sequence-specific manner. AP-1 family consists of hetero- and homodimers of bZIP (basic region leucine zipper) proteins, mainly of Jun-Jun, Jun-Fos or Jun-ATF. AP-1 members are involved in the regulation of a number of cellular processes including cell growth, proliferation, survival, apoptosis, differentiation, cell migration. The ability of a single transcription factor to determine a cell fate critically depends on the relative abundance of AP-1 subunits, the composition of AP-1 dimers, the quality of stimulus, the cell type, the co-factor assembly. AP-1 activity is regulated on multiple levels; transcriptional, translational and post-translational control mechanisms contribute to the balanced production of AP-1 proteins and their functions. Briefly, regulation occurs through: effects on jun, fos, atf gene transcription and mRNA turnover. AP-1 protein members turnover. post-translational modifications of AP-1 proteins that modulate their transactivation potential (effect of protein kinases or phosphatases). interactions with other transcription factors that can either induce or interfere with AP-1 activity.More...
Mitogen activated protein kinase. There are three major grou......
Mitogen activated protein kinase. There are three major groups of MAP kinases the extracellular signal-regulated protein kinases ERK1/2. the p38 MAP kinase. the c-Jun NH-terminal kinases JNK. ERK1 and ERK2 are activated in response to growth stimuli. Both JNKs and p38-MAPK are activated in response to a variety of cellular and environmental stresses. The MAP kinases are activated by dual phosphorylation of Thr and Tyr within the tripeptide motif Thr-Xaa-Tyr. The sequence of this tripeptide motif is different in each group of MAP kinases: ERK (Thr-Glu-Tyr); p38 (Thr-Gly-Tyr); and JNK (Thr-Pro-Tyr). MAPK activation is mediated by signal transduction in the conserved three-tiered kinase cascade: MAPKKKK (MAP4K or MKKKK or MAPKKK Kinase) activates the MAPKKK. The MAPKKKs then phosphorylates a dual-specificity protein kinase MAPKK, which in turn phosphorylates the MAPK. The dual specificity MAP kinase kinases (MAPKK or MKK) differ for each group of MAPK. The ERK MAP kinases are activated by the MKK1 and MKK2; the p38 MAP kinases are activated by MKK3, MKK4, and MKK6; and the JNK pathway is activated by MKK4 and MKK7. The ability of MAP kinase kinases (MKKs, or MEKs) to recognize their cognate MAPKs is facilitated by a short docking motif (the D-site) in the MKK N-terminus, which binds to a complementary region on the MAPK. MAPKs then recognize many of their targets using the same strategy, because many MAPK substrates also contain D-sites. The upstream signaling events in the TLR cascade that initiate and mediate the ERK signaling pathway remain unclear.More...
Humans are exposed to millions of potential pathogens daily,......
Humans are exposed to millions of potential pathogens daily, through contact, ingestion, and inhalation. Our ability to avoid infection depends on the adaptive immune system and during the first critical hours and days of exposure to a new pathogen, our innate immune system.More...
Innate immunity encompases the nonspecific part of immunity ......
Innate immunity encompases the nonspecific part of immunity tha are part of an individual's natural biologic makeupMore...
MAPKs are protein kinases that, once activated, phosphorylat......
MAPKs are protein kinases that, once activated, phosphorylate their specific cytosolic or nuclear substrates at serine and/or threonine residues. Such phosphorylation events can either positively or negatively regulate substrate, and thus entire signaling cascade activity. The major cytosolic target of activated ERKs are RSKs. Other ERK nuclear targets include c-Myc, HSF1 (Heat-Shock Factor-1), STAT1/3 (Signal Transducer and Activator of Transcription-1/3), and many more transcription factors. Activated p38 MAPK is able to phosphorylate a variety of substrates, including transcription factors STAT1, p53, ATF2 (Activating transcription factor 2), MEF2 (Myocyte enhancer factor-2), protein kinases MSK1, MNK, MAPKAPK2/3, death/survival molecules (Bcl2, caspases), and cell cycle control factors (cyclin D1). JNK, once activated, phosphorylates a range of nuclear substrates, including transcription factors Jun, ATF, Elk1, p53, STAT1/3 and many other factors. JNK has also been shown to directly phosphorylate many nuclear hormone receptors. For example, peroxisome proliferator-activated receptor 1 (PPAR-1) and retinoic acid receptors RXR and RAR are substrates for JNK. Other JNK targets are heterogeneous nuclear ribonucleoprotein K (hnRNP-K) and the Pol I-specific transcription factor TIF-IA, which regulates ribosome synthesis. Other adaptor and scaffold proteins have also been characterized as nonnuclear substrates of JNK.More...
In human, together with ubiquitin-conjugating E2-type enzyme......
In human, together with ubiquitin-conjugating E2-type enzymes UBC13 and UEV1A and IKK(NEMO), leading to the activation of the kinases. Xia et all., 2009 demonstrated in vitro that unlike polyubiquitin chains covalently attached to TRAF6 or IRAK, TAB2 and NEMO-associated ubiquitin chains were found to be unanchored and susceptible to N-terminal ubiquitin cleavage. Only K63-linked polyubiquitin chains, but not monomeric ubiquitin, activated TAK1 in a dose-dependent manner.Optimal activation of the IKK complex was achieved using ubiquitin polymers containing both K48 and K63 linkages. Furthermore, the authors proposed that the TAK1 complexes might be brougt in close proximity by binding several TAB2/3 to a single polyubiquitin chain to facilitate TAK1 kinases trans-phosphorylation. Alternativly, the possibility that polyUb binding promotes allosteric activation of TAK1 complex should be considered.More...
Toll-like receptor 3 (TLR3) as was shown for mammals is expr......
Toll-like receptor 3 (TLR3) as was shown for mammals is expressed on myeloid dendritic cells, respiratory epithelium, macrophages, and appears to play a central role in mediating the antiviral and inflammatory responses of the innate immunity in combating viral infections. Mammalian TLR3 recognizes dsRNA, and that triggers the receptor to induce the activation of NF-kappaB and the production of type I interferons (IFNs). dsRNA-stimulated phosphorylation of two specific TLR3 tyrosine residues (Tyr759 and Tyr858) is essential for initiating TLR3 signaling pathways.More...
FOS related interactors from protein-protein interaction data in HPRD (count: 54)
Basic Information
Positive relationships between FOS and other components at different levels (count: 1)
