Our findings demonstrate significant dysregulation of synapt......
Our findings demonstrate significant dysregulation of synaptic function/structure related genes SNAP25, DLG2 (SAP93), and MAP1A, and 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid receptor subunit genes GLUR1 and GLUR3More...
Positive relationships between SNAP25 and other components at different levels (count: 0)
Positive relationship network of SNAP25 in MK4MDD
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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
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If the mapped gene or protein is not from literature, square node would be used instead of Circle node.
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3. The network is generated using Cytoscape Web
Negative relationships between SNAP25 and MDD (count: 0)
Negative relationships between SNAP25 and other components at different levels (count: 0)
VAMP/synaptobrevin, SNAP-25 and syntaxin are important for s......
VAMP/synaptobrevin, SNAP-25 and syntaxin are important for synaptic vesicle fusion at the nerve terminal. These proteins constitute the synaptic members of SNARE family. These proteins are involved in docking and/or fusion of synaptic vesicles with the presynaptic membrane. BoNTs achieve total blockage of neurotransmitter release by selectively inactivating the synaptic SNAREs by proteolysis. The L chains of BoNTs of different serotypes specifically cleave distinct members of the SNARE family: serotypes B, D, F and G act on VAMP/synaptobrevin localized on synaptic vesicles; BoNT-A and E cleave SNAP-25; and BoNT-C cleaves both syntaxin 1 and SNAP-25, two proteins of the pre-synaptic plasma membrane. Sudhof et al. and Liu et al. had observed that alpha-laterotoxins from black widow spider target identical neurmuscular junctions by opposite mechanism resulting in massive vesicle exocytosis. The exact molecular details of the action of these toxins may reveal the underlying processes of synaptic vesicle exocytosis/inbition and their regulation.More...
Neurotransmitter is stored in the synaptic vesicle in the pr......
Neurotransmitter is stored in the synaptic vesicle in the pre-synaptic terminal prior to its release in the synaptic cleft upon depolarization of the pre-synaptic membrane. The release of the neurotransmitter is a multi-step process that is controlled by electrical signals passing through the axons in form of action potential. Neurotransmitters include glutamate, acetylcholine, nor-epinephrine, dopamine and seratonin. Each of the neurotransmitter cycle is independently described.More...
Serotonin is synthesized in the serotonergic neurons in the ......
Serotonin is synthesized in the serotonergic neurons in the central nervous system and the enterochrommaffin cells of the gastroinetstinal system. Serotonin is loaded into the clathrin sculpted monoamine transport vesicles. The vesicles are docked, primed and release after the change in the membrane potential that activates voltage gated calcium channels and the reponse by several proetins to the changes in intracellular Ca2+ increase leads to fusion of the vesicle and release of serotonin into the synapse.More...
Dopamine neurotransmitter cycle occurs in dopaminergic neuro......
Dopamine neurotransmitter cycle occurs in dopaminergic neurons. Dopamine is synthesized and loaded into the clathrin sculpted monoamine transport vesicles. The vesicles are docked, primed and fused with the plasmamembrane in the synapse to release dopamine into the synaptic cleft.More...
Chemical synapses are specialized junctions that are used fo......
Chemical synapses are specialized junctions that are used for communication between neurons, neurons and muscle or gland cells. The synapse involves a pre-synaptic neuron and a post-synaptic neuron, muscle cell or glad cell. The pre and the post-synaptic cell are separated by a gap of 20nm called the synaptic cleft. The signals pass in a unidirection from pre-synaptic to post-synaptic. The pre-synaptic neuron communicates via the release of neurotransmitter which bind the receptors on the post-synaptic cell.More...
Communication at the synapse involves the release of glutama......
Communication at the synapse involves the release of glutamate from the presynaptic neuron and its binding to glutamate receptors on the postsynaptic cell to generate a series of events that lead to propagation of the synaptic transmission. This process begins with the formation of synaptic vesicles in the presynaptic neuron, proceeds to the loading of glutamate into the vesicles, and concludes with the release of glutamate into the synaptic cleft. The glutamate life cycle in the neuron begins with the loading of the nascent synaptic vesicles with cytosolic glutamate with the help the transporter protein, VGLUT1, located in the synaptic vesicular membrane. Glutamate loaded vesicles are formed in the cytoplasm and then transported to a site close to the plasma membrane where the vesicle is docked with the help of several proteins. One of the key players in the docking process in Munc 18, which interacts with syntaxin (in the plasma membrane), MINT (Munc18 interacting molecule), and DOC2. These interactions along with the secondary interactions are needed for docking the synaptic vesicle to the plasma membrane. The docked synaptic vesicle is not ready for release until it undergoes molecular changes to prime it for fusion with the plasma membrane. Munc13 is one of the main players in the priming process. Munc 13 interacts with RIM (Rab3A interacting molecule) located in the synaptic vesicle. Munc 13 also interacts with DOC2. The precise molecular mechanisms of the interactions that result in docking versus priming are not clear and the docking and priming process have been combined in this annotation of this pathway. Once primed the synaptic vesicle is ready for release. Synaptic transmission involves an action potential that is generated in the presynaptic cell which induces the opening of voltage gated Ca2+ channels (VGCC) located in the plasma membrane of the presynaptic neuron. Typically N, P/Q and R type of VGCCs are involved in the neurotransmitter release. Ca2+ influx through these channels results in the rise of intracellular Ca2+ concentration. In the microdomain of glutamatergic synapses, the Ca2+ concentration could rise between 10-25 micro molar. Synaptotagmin, a Ca2+-binding protein located in the synaptic vesicular membrane, responds to the rise in the Ca2+ levels in the microdomain and induces a synaptic vesicle membrane curvature that favors vesicle fusion. Fusion of the synaptic vesicle with the plasma membrane is characterized by the formation of a trimeric trans-SNARE complex that involves VAMP2 from the synaptic vesicle membrane, and syntaxin and SNAP-25 from plasma membrane. Vesicle fusion incorporates the synaptic vesicle membrane into the plasma membrane, releasing the vesicle contents (glutamate) into the synaptic cleft. Postfusion the synaptic vesicle membrane proteins (VAMP2, Rab3A, VGLUT1, and synaptotagmin) are also found in the plasma membrane.More...
Increased blood glucose levels from dietary carbohydrate nor......
Increased blood glucose levels from dietary carbohydrate normally trigger insulin release from the beta cells of the pancreas. Glucose catabolism in the beta cell is the transducer that links increased glucose levels to insulin release. Glucose uptake and glycolysis generate cytosolic pyruvate; pyruvate is transported to mitochondria and converted both to oxaloacetate which increases levels of TCA cycle intermediates, and to acetyl-CoA which is oxidized to CO2 via the TCA cycle. The rates of ATP synthesis and transport to the cytosol increase, plasma membrane ATP-sensitive inward rectifying potassium channels. Elevated calcium concentrations near the plasma membrane cause insulin secretion in two phases: an initial high rate within minutes of glucose stimulation and a slow, sustained release lasting longer than 30 minutes. In the initial phase, 50-100 insulin granules already docked at the membrane are exocytosed. Exocytosis is rendered calcium-dependent by Synaptotagmin V/IX, a calcium-binding membrane protein located in the membrane of the docked granule, although the exact action of Synapototagmin in response to calcium is unknown. Calcium also causes a translocation of reserve granules within the cell towards the plasma membrane for release in the second, sustained phase of secretion. Human cells contain L-type.More...
Acetylcholine released by parasympathetic nerve endings in t......
Acetylcholine released by parasympathetic nerve endings in the pancreas causes a potentiation of insulin release when glucose is present at concentrations greater than about 7 mM. Acetylcholine binds the Muscarinic Acetylcholine Receptor M3 on pancreatic beta cells. The binding has two effects: an increase in permeability of the cell to Na+ ions through an unknown mechanism, and the activation of Phospholipase C beta-1 through a heterotrimeric G protein, G(q). After acetylcholine binds the Muscarinic Acetycholine Receptor M3, the receptor activates the G protein Gq by causing the alpha subunit of Gq to exchange GDP for GTP. Activation of Gq in turn activates Phospholipase C beta-1. Phospholipase C beta-1 hydrolyzes the phosphodiester bond at the third position of phosphoinositol 4,5-bisphosphate, producing diacylglycerols (DAG) and inositol 1,4,5-trisphosphate. DAG remains in the cell membrane and causes Protein Kinase C alpha (PKC alpha) to translocate from the cytosol to the membrane. This results in the activation of PKC alpha which then phosphorylates target proteins on serine and threonine residues. One known target of PKC alpha is Myristoylated Alanine-rich C Kinase Substrate (MARCKS), which is believed to affect vesicle transport and may be responsible for the increased traffic of insulin granules seen in response to acetylcholine. Inositol trisphophate binds a receptor, the IP3 receptor, on calcium stores in the cell (probably the endoplasmic reticulum). The release of calcium into the cytosol stimulates the exocytosis of insulin granules.More...
Glucagon-like Peptide-1 (GLP-1) is secreted by L-cells in th......
Glucagon-like Peptide-1 (GLP-1) is secreted by L-cells in the intestine in response to glucose and fatty acids. GLP-1 circulates to the beta cells of the pancreas where it binds a G-protein coupled receptor, GLP-1R, on the plasma membrane. The binding activates the heterotrimeric G-protein G(s), causing the alpha subunit of G(s) to exchange GDP for GTP and dissociate from the beta and gamma subunits. The activated G(s) alpha subunit interacts with Adenylyl Cyclase VIII (Adenylate Cyclase VIII, AC VIII) and activates AC VIII to produce cyclic AMP (cAMP). cAMP then has two effects: 1) cAMP activates Protein Kinase A (PKA), and 2) cAMP activates Epac1 and Epac2, two guanyl nucleotide exchange factors. Binding of cAMP to PKA causes the catalytic subunits of PKA to dissociate from the regulatory subunits and become an active kinase. PKA is known to enhance insulin secretion by closing ATP-sensitive potassium channels, closing voltage-gated potassium channels, releasing calcium from the endoplasmic reticulum, and affecting insulin secretory granules. The exact mechanisms for PKA's action are not fully known. After prolonged increases in cAMP, PKA translocates to the nucleus where it regulates the PDX-1 and CREB transcription factors, activating transcription of the insulin gene. cAMP produced by AC VIII also activates Epac1 and Epac2, which catalyze the exchange of GTP for GDP on G-proteins, notably Rap1A.. Rap1A regulates insulin secretory granules and is believed to activate the Raf/MEK/ERK mitogenic pathway leading to proliferation of beta cells. The Epac proteins also interact with RYR calcium channels on the endoplasmic reticulum, the SUR1 subunits of ATP-sensitive potassium channels, and the Piccolo:Rim2 calcium sensor at the plasma membrane.More...
Pancreatic beta cells integrate signals from several metabol......
Pancreatic beta cells integrate signals from several metabolites and hormones to control the secretion of insulin. In general, glucose triggers insulin secretion while other factors can amplify or inhibit the amount of insulin secreted in response to glucose. Factors which increase insulin secretion include the incretin hormones Glucose-dependent insulinotropic polypeptide (GIP and glucagon-like peptide-1 (GLP-1), acetylcholine, and fatty acids. Factors which inhibit insulin secretion include adrenaline and noradrenaline.More...
Acetylcholine neurotransmitter release cycle involves synthe......
Acetylcholine neurotransmitter release cycle involves syntheis of choline, loading of clathrin scultpted synaptic vesicles, docking and priming of the acetyl choline loaded synaptic vesicles and then release of acetylcholine. This cycle occurs in neurons of central nervous system (CNS), peripheral, autonomic and somatic nervous system. In the CNS, the acetylcholine is released by the presynaptic neurons into the synaptic cleft where the released acetylcholine is accessible to acetylcholine receptors located on the postsynaptic neurons.More...
Many hormones that affect individual physiological processes......
Many hormones that affect individual physiological processes including the regulation of appetite, absorption, transport, and oxidation of foodstuffs influence energy metabolism pathways. While insulin mediates the storage of excess nutrients, glucagon is involved in the mobilization of energy resources in response to low blood glucose levels, principally by stimulating hepatic glucose output. Small doses of glucagon are sufficient to induce significant glucose elevations. These hormone-driven regulatory pathways enable the body to sense and respond to changed amounts of nutrients in the blood and demands for energy. Glucagon and Insulin act through various metabolites and enzymes that target specific steps in metabolic pathways for sugar and fatty acids. The processes responsible for the long-term control of fat synthesis and short term control of glycolysis by key metabolic products and enzymes are annotated in this module as six specific pathways: Pathway 1. Glucagon signalling in metabolic pathways: In response to low blood glucose, pancreatic alpha-cells release glucagon. The binding of glucagon to its receptor results in increased cAMP synthesis, and Protein Kinase A - Copyright National Academy of Sciences, U.S.A.).More...
Noradrenalin release cycle consists of reacidification of th......
Noradrenalin release cycle consists of reacidification of the empty clathrin sculpted monoamine transport vesicle, loading of dopamine into reacidified clathrin coated monamine transport vesicle, conversion of dopamine into Noradrenalin, docking and priming of the noradrenalin synaptic veiscle and then release of noradrenalin synaptic vesicle. In the peripheral nervous system in the peripheral nervous system noradrenalin is stored in large and small dense vesicles and is realesed from large vesicles.More...
Free fatty acids augment the glucose-triggered secretion of ......
Free fatty acids augment the glucose-triggered secretion of insulin. The augmentation is believed to be due to the additive effects of the activation of the free fatty acid receptor 1 (FFAR1 or GPR40) and the metabolism of free fatty acids within the pancreatic beta cell. This module describes each pathway.More...
Synthesis of insulin-containing secretory granules can be de......
Synthesis of insulin-containing secretory granules can be described in 6 steps: transcription of preproinsulin genes, translation of preproinsulin mRNA with concomitant removal of the signal peptide, formation of intramolecular disulfide bonds, formation of proinsulin-zinc-calcium complexes, proteolytic cleavage of proinsulin to yield insulin, translocation of the granules across the cytosol to the plasma membrane. Transcription of the human insulin gene INS is activated by 4 important transcription factors: Pdx-1, MafA, Beta2/NeuroD1, and E47. The transcription factors interact with each other at the promoters of the insulin gene and act synergistically to promote transcription. Expression of the transcription factors is upregulated in response to glucose. The preproinsulin mRNA is translated by ribosomes at the rough endoplasmic reticulum (ER) and the preproinsulin enters the secretion pathway by virtue of its signal peptide, which is cleaved during translation to yield proinsulin. Evidence indicates that the preproinsulin mRNA is stabilized by glucose. Within the ER, three intramolecular disulfide bonds form between cysteine residues in the proinsulin. Formation of the bonds is the spontaneous result of the conformation of proinsulin and the oxidizing environment of the ER, which is maintained by Ero1-like alpha The cystine bonded proinsulin then moves via vesicles from the ER to the Golgi Complex. High concentrations of zinc are maintained in the Golgi by zinc transporters ZnT5, ZnT6, and ZnT7 and the proinsulin forms complexes with zinc and calcium. Proinsulin-zinc-calcium complexes bud in vesicles from the trans-Golgi to form immature secretory vesicles (secretory granules) in the cytosol. Within the immature granules the endoproteases Prohormone Convertase 1/3 and Prohormone Convertase 2 cleave at two sites of the proinsulin and Carboxypeptidase E removes a further 4 amino acid residues to yield the cystine-bonded A and B chains of mature insulin and the C peptide, which will also be secreted with the insulin. The insulin-zinc-calcium complexes form insoluble crystals within the granule The insulin-containing secretory granules are then translocated across the cytosol to the inner surface of the plasma membrane. Translocation occurs initially by attachment of the granules to Kinesin-1, which motors along microtubules, and then by attachment to Myosin Va, which motors along the microfilaments of the cortical actin network. A pancreatic beta cell contains about 10000 insulin granules of which about 1000 are docked at the plasma membrane and 50 are readily releasable in immediate response to stimulation by glucose or other secretogogues. Docking is due to interaction between the Exocyst proteins EXOC3 on the granule membrane and EXOC4 on the plasma membrane. Exocytosis is accomplished by interaction between SNARE-type proteins Syntaxin 1A and Syntaxin 4 on the plasma membrane and Synaptobrevin-2/VAMP2 on the granule membrane. Exocytosis is a calcium-dependent process due to interaction of the calcium-binding membrane protein Synaptotagmin V/IX with the SNARE-type proteins.More...
Botulism, caused by botulinum neurotoxin. According to their......
Botulism, caused by botulinum neurotoxin. According to their antigenic properties, BoNTs are classified into seven different toxin types. The toxin is released as a 900 kDa complex containing some accessory proteins of unknown functions. The toxin types A, B and E are mainly involved in human botulism whereas C and D predominantly cause animal botulism. The toxin is absorbed from the gut or other epithelium and reaches neuromuscular junctions by transcytosis. The binding sites for the toxins are distributed across the apical surface of the epithelium. It has been observed that the neurotoxin alone is capable of transcytosis across epithelial cells. Once internalized, the neurotoxin is dissociated from the non-toxic components of the progenitor toxin in endosome. The neurological inhibition is caused by the specific cleavage of a group of proteins integral to NMJ exocytosis, SNARE proteins (soluble NSF-attachment protein receptors). One or more SNARE proteins are cleaved by BoNT, blocking the release of synaptic vesicular contents like acetylcholine as in the case of motor neurons. BoNTs are synthesized as polypeptides of 150 kDa that are cleaved into heavy and light chains linked by a single disulfide bond. Cleavage takes place within a surface-exposed loop at the N-terminal of the Heavy chain subunit. Both bacterial and host endopeptidases can catalyze BoNT cleavage into heavy and light chains, but bacterial enzymes are thought to carry out this function in vivo.The Heavy Chain (HC) has two 50 kDa functional domains: the N-terminal translocation domain is capable of forming channels in lipid bilayers; the C-terminal ganglioside-binding domain is important for membrane binding and subsequent internalization of toxins by host neurons. The 50 kDa Light chain (LC) is a zinc-dependent endopeptidase specific for core components of neurotransmitter release complexes. BoNT action proceeds in the following steps: binding of cleaved toxin to the target cell membrane; transcytosis from epithelial membrane to target neuromuscular junction cells; release of BoNT Light chain into the target cell cytosol; and proteolytic cleavage of target cell proteins catalyzed by the BoNT Light chain.More...
SNAP25 related interactors from protein-protein interaction data in HPRD (count: 27)
Basic Information
Positive relationships between SNAP25 and other components at different levels (count: 0)
