Gene Symbol: Snap25
Description: synaptosome associated protein 25
Alias: SNAP-25B, SNAP-25a, synaptosomal-associated protein 25, SNAP-25, SUP, super protein, synaptosomal-associated 25 kDa protein, synaptosomal-associated protein, 25 kDa
Species: rat
Products:     Snap25

Top Publications

  1. Fan H, Fan F, Bao L, Pei G. SNAP-25/syntaxin 1A complex functionally modulates neurotransmitter gamma-aminobutyric acid reuptake. J Biol Chem. 2006;281:28174-84 pubmed
    ..Thus our findings delineate a further molecular mechanism for the regulation of GABA reuptake by a target SNARE complex and suggest a direct coordination between GABA release and reuptake. ..
  2. Walter A, Wiederhold K, Bruns D, Fasshauer D, Sørensen J. Synaptobrevin N-terminally bound to syntaxin-SNAP-25 defines the primed vesicle state in regulated exocytosis. J Cell Biol. 2010;188:401-13 pubmed publisher
    ..Our data are consistent with a model in which the N terminus of the SNARE complex assembles during vesicle priming, followed by Ca(2+)-triggered C-terminal assembly and membrane fusion...
  3. Ernst J, Brunger A. High resolution structure, stability, and synaptotagmin binding of a truncated neuronal SNARE complex. J Biol Chem. 2003;278:8630-6 pubmed
    ..The truncated SNARE complex is monomeric, and it retains binding to synaptotagmin I. ..
  4. Weninger K, Bowen M, Choi U, Chu S, Brunger A. Accessory proteins stabilize the acceptor complex for synaptobrevin, the 1:1 syntaxin/SNAP-25 complex. Structure. 2008;16:308-20 pubmed publisher
    ..In the cellular environment the binary complex is actively maintained in a configuration where it can rapidly interact with synaptobrevin, so formation is not likely a limiting step for neurotransmitter release. ..
  5. Pobbati A, Razeto A, Böddener M, Becker S, Fasshauer D. Structural basis for the inhibitory role of tomosyn in exocytosis. J Biol Chem. 2004;279:47192-200 pubmed
    ..Moreover, data bank searches revealed that the R-SNARE motif of tomosyn is highly conserved throughout all eukaryotic kingdoms. This suggests that the formation of a tight SNARE complex is important for the function of tomosyn. ..
  6. Wu C, Lin J, Chien C, Chang W, Lai H, Chang C, et al. Type VI adenylyl cyclase regulates neurite extension by binding to Snapin and Snap25. Mol Cell Biol. 2011;31:4874-86 pubmed publisher
    ..catalyzes cAMP synthesis, regulates neurite outgrowth by direct interaction with a binding protein (Snapin) of Snap25 at the N terminus of AC6 (AC6-N). We first showed that AC6 expression increased during postnatal brain development...
  7. Salaun C, Gould G, Chamberlain L. Lipid raft association of SNARE proteins regulates exocytosis in PC12 cells. J Biol Chem. 2005;280:19449-53 pubmed
    b>SNAP25 and SNAP23 are plasma membrane SNARE proteins essential for regulated exocytosis in diverse cell types...
  8. Pobbati A, Stein A, Fasshauer D. N- to C-terminal SNARE complex assembly promotes rapid membrane fusion. Science. 2006;313:673-6 pubmed
    ..Thus, SNAREs do have the capacity to execute fusion at a speed required for neuronal secretion, demonstrating that the maintenance of acceptor complexes is a critical step in biological fusion reactions. ..
  9. Wang D, Zhang Z, Dong M, Sun S, Chapman E, Jackson M. Syntaxin requirement for Ca2+-triggered exocytosis in neurons and endocrine cells demonstrated with an engineered neurotoxin. Biochemistry. 2011;50:2711-3 pubmed publisher
    ..These mutants can generate syntaxin-free cells as a useful experimental system for research and may lead to pharmaceuticals that target syntaxin selectively. ..

More Information


  1. Condliffe S, Corradini I, Pozzi D, Verderio C, Matteoli M. Endogenous SNAP-25 regulates native voltage-gated calcium channels in glutamatergic neurons. J Biol Chem. 2010;285:24968-76 pubmed publisher
    ..Overall, this study demonstrates that endogenous SNAP-25 negatively regulates native VGCCs in glutamatergic neurons which could have important implications for neurological diseases associated with altered SNAP-25 expression. ..
  2. Washbourne P, Thompson P, Carta M, Costa E, Mathews J, Lopez Bendito G, et al. Genetic ablation of the t-SNARE SNAP-25 distinguishes mechanisms of neuroexocytosis. Nat Neurosci. 2002;5:19-26 pubmed
    ..These results demonstrate that the development of neurotransmission requires the recruitment of a specialized SNARE core complex to meet the demands of regulated exocytosis. ..
  3. Greaves J, Gorleku O, Salaun C, Chamberlain L. Palmitoylation of the SNAP25 protein family: specificity and regulation by DHHC palmitoyl transferases. J Biol Chem. 2010;285:24629-38 pubmed publisher
    b>SNAP25 plays an essential role in neuronal exocytosis pathways. SNAP25a and SNAP25b are alternatively spliced isoforms differing by only nine amino acids, three of which occur within the palmitoylated cysteine-rich domain...
  4. Gerber S, Rah J, Min S, Liu X, de Wit H, Dulubova I, et al. Conformational switch of syntaxin-1 controls synaptic vesicle fusion. Science. 2008;321:1507-10 pubmed publisher
    ..Thus, the closed conformation of syntaxin-1 gates the initiation of the synaptic vesicle fusion reaction, which is then mediated by SNARE-complex/Munc18-1 assemblies. ..
  5. Fasshauer D, Antonin W, Margittai M, Pabst S, Jahn R. Mixed and non-cognate SNARE complexes. Characterization of assembly and biophysical properties. J Biol Chem. 1999;274:15440-6 pubmed
  6. Sutton R, Fasshauer D, Jahn R, Brunger A. Crystal structure of a SNARE complex involved in synaptic exocytosis at 2.4 A resolution. Nature. 1998;395:347-53 pubmed
    ..These characteristics may be important for membrane fusion and for the binding of regulatory factors affecting neurotransmission. ..
  7. Hess D, Slater T, Wilson M, Skene J. The 25 kDa synaptosomal-associated protein SNAP-25 is the major methionine-rich polypeptide in rapid axonal transport and a major substrate for palmitoylation in adult CNS. J Neurosci. 1992;12:4634-41 pubmed
    ..This polypeptide, designated "super protein" (SuP), is the most prominent species among methionine-labeled proteins conveyed by rapid axonal ..
  8. Mandolesi G, Vanni V, Cesa R, Grasselli G, Puglisi F, Cesare P, et al. Distribution of the SNAP25 and SNAP23 synaptosomal-associated protein isoforms in rat cerebellar cortex. Neuroscience. 2009;164:1084-96 pubmed publisher
    Synaptosome-associated protein of 25 kDa (SNAP25) is a component of the fusion complex that mediates synaptic vesicle exocytosis, regulates calcium dynamics and neuronal plasticity...
  9. Tokumaru H, Shimizu Okabe C, Abe T. Direct interaction of SNARE complex binding protein synaphin/complexin with calcium sensor synaptotagmin 1. Brain Cell Biol. 2008;36:173-89 pubmed publisher
    ..We propose that synaphin recruits synaptotagmin 1 to the SNARE-based fusion complex and synergistically functions with synaptotagmin 1 in mediating fast synaptic vesicle exocytosis. ..
  10. Selak S, Paternain A, Aller M, Aller I, Picó E, Rivera R, et al. A role for SNAP25 in internalization of kainate receptors and synaptic plasticity. Neuron. 2009;63:357-71 pubmed publisher
    ..Regulatory elements for synaptic kainate receptors (KARs) are, however, largely undetermined. We have found that SNAP25 is critical for the synaptic removal of KARs, acting via GluK5 (i.e., KA2) subunits...
  11. Salaun C, Gould G, Chamberlain L. The SNARE proteins SNAP-25 and SNAP-23 display different affinities for lipid rafts in PC12 cells. Regulation by distinct cysteine-rich domains. J Biol Chem. 2005;280:1236-40 pubmed
    ..These different raft-targeting signals within SNAP-25 and SNAP-23 are likely important for fine-tuning the exocytic pathways in which these proteins operate. ..
  12. An S, Almers W. Tracking SNARE complex formation in live endocrine cells. Science. 2004;306:1042-6 pubmed
    Syntaxin, synaptosome-associated protein of 25 kD (SNAP25), and vesicle-associated membrane protein/synaptobrevin are collectively called SNAP receptor (SNARE) proteins, and they catalyze neuronal exocytosis by forming a "core ..
  13. Hata Y, Sudhof T. A novel ubiquitous form of Munc-18 interacts with multiple syntaxins. Use of the yeast two-hybrid system to study interactions between proteins involved in membrane traffic. J Biol Chem. 1995;270:13022-8 pubmed
    ..The lack of specificity of the interactions between syntaxins and Munc-18s indicates that specificity of membrane trafficking reactions is not dependent on this interaction. ..
  14. Okamoto M, Sudhof T. Mints, Munc18-interacting proteins in synaptic vesicle exocytosis. J Biol Chem. 1997;272:31459-64 pubmed
    ..F. J. (1995) Nature 374, 173-177). Our data suggest a model whereby local production of phosphatidylinositol phosphates may trigger the binding of vesicles to the active zone via the Mint.Munc18-1 complex in conjunction with syntaxin 1. ..
  15. Verderio C, Pozzi D, Pravettoni E, Inverardi F, Schenk U, Coco S, et al. SNAP-25 modulation of calcium dynamics underlies differences in GABAergic and glutamatergic responsiveness to depolarization. Neuron. 2004;41:599-610 pubmed
    ..SNAP-25 is therefore a multifunctional protein that participates in exocytotic function both at the mechanistic and at the regulatory level. ..
  16. Margittai M, Fasshauer D, Jahn R, Langen R. The Habc domain and the SNARE core complex are connected by a highly flexible linker. Biochemistry. 2003;42:4009-14 pubmed
    ..We conclude that the linker region exhibits a high degree of conformational flexibility. ..
  17. Lang T, Bruns D, Wenzel D, Riedel D, Holroyd P, Thiele C, et al. SNAREs are concentrated in cholesterol-dependent clusters that define docking and fusion sites for exocytosis. EMBO J. 2001;20:2202-13 pubmed
    ..This suggests that high local concentrations of SNAREs are required for efficient fusion. ..
  18. Lang T, Margittai M, Hölzler H, Jahn R. SNAREs in native plasma membranes are active and readily form core complexes with endogenous and exogenous SNAREs. J Cell Biol. 2002;158:751-60 pubmed
    ..SNAP) receptor (SNARE) synaptobrevin 2 forms complexes with the plasma membrane-bound SNAREs syntaxin 1A and SNAP25 to initiate the fusion reaction...
  19. Xu J, Luo F, Zhang Z, Xue L, Wu X, Chiang H, et al. SNARE proteins synaptobrevin, SNAP-25, and syntaxin are involved in rapid and slow endocytosis at synapses. Cell Rep. 2013;3:1414-21 pubmed publisher
    ..The dual role of three SNARE proteins in exo- and endocytosis suggests that SNARE proteins may be molecular substrates contributing to the exocytosis-endocytosis coupling, which maintains exocytosis in secretory cells. ..
  20. Vikman J, Ma X, Hockerman G, Rorsman P, Eliasson L. Antibody inhibition of synaptosomal protein of 25 kDa (SNAP-25) and syntaxin 1 reduces rapid exocytosis in insulin-secreting cells. J Mol Endocrinol. 2006;36:503-15 pubmed
    ..Our data are consistent with the concept that both syntaxin 1 and SNAP-25 are required for rapid exocytosis in beta-cells. ..
  21. Sidor Kaczmarek J, Labuda C, Litwinowicz B, Spodnik J, Kowiański P, Dziewiatkowski J, et al. Developmental expression of SNAP-25 protein in the rat striatum and cerebral cortex. Folia Morphol (Warsz). 2004;63:285-8 pubmed
    ..Two peaks are observed, the first on P10 and the second on P60, after which the expression level decreases. These results appear to confirm the role of SNAP-25 protein in axon outgrowth and synaptogenesis in the nervous system. ..
  22. Grumelli C, Berghuis P, Pozzi D, Caleo M, Antonucci F, Bonanno G, et al. Calpain activity contributes to the control of SNAP-25 levels in neurons. Mol Cell Neurosci. 2008;39:314-23 pubmed publisher
  23. Arunachalam L, Han L, Tassew N, He Y, Wang L, Xie L, et al. Munc18-1 is critical for plasma membrane localization of syntaxin1 but not of SNAP-25 in PC12 cells. Mol Biol Cell. 2008;19:722-34 pubmed
  24. Hu S, Christie M, Saez N, Latham C, Jarrott R, Lua L, et al. Possible roles for Munc18-1 domain 3a and Syntaxin1 N-peptide and C-terminal anchor in SNARE complex formation. Proc Natl Acad Sci U S A. 2011;108:1040-5 pubmed publisher
    ..We hypothesize that Munc18-1 domain 3a undergoes a conformational change that may allow coiled-coil interactions with SNARE complexes. ..
  25. Karlsen A, Rath M, Rohde K, Toft T, Møller M. Developmental and diurnal expression of the synaptosomal-associated protein 25 (Snap25) in the rat pineal gland. Neurochem Res. 2013;38:1219-28 pubmed publisher
    b>Snap25 (synaptosomal-associated protein) is a 25 kDa protein, belonging to the SNARE-family (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) of proteins, essential for synaptic and secretory vesicle exocytosis...
  26. Shin O, Rhee J, Tang J, Sugita S, Rosenmund C, Sudhof T. Sr2+ binding to the Ca2+ binding site of the synaptotagmin 1 C2B domain triggers fast exocytosis without stimulating SNARE interactions. Neuron. 2003;37:99-108 pubmed
    ..Thus, triggering of the fast component of release by Sr(2+) as a Ca(2+) agonist involves the formation of synaptotagmin/phospholipid complexes, but does not require stimulated SNARE binding. ..
  27. Prescott G, Chamberlain L. Regional and developmental brain expression patterns of SNAP25 splice variants. BMC Neurosci. 2011;12:35 pubmed publisher
    b>SNAP25 is an essential SNARE protein for regulated exocytosis in neuronal cells. Differential splicing of the SNAP25 gene results in the expression of two transcripts, SNAP25a and SNAP25b...
  28. Batista T, Ribeiro R, Amaral A, de Oliveira C, Boschero A, Carneiro E. Taurine supplementation restores glucose and carbachol-induced insulin secretion in islets from low-protein diet rats: involvement of Ach-M3R, Synt 1 and SNAP-25 proteins. J Nutr Biochem. 2012;23:306-12 pubmed publisher
    ..The latter effect involves the normalization of the cholinergic pathway, associated with the preservation of exocytotic proteins...
  29. Aikawa Y, Lynch K, Boswell K, Martin T. A second SNARE role for exocytic SNAP25 in endosome fusion. Mol Biol Cell. 2006;17:2113-24 pubmed
    ..Synaptosome-associated protein of 25 kDa (SNAP25) is a plasma membrane Q (containing glutamate)-SNARE essential for Ca2+-dependent secretory vesicle-plasma ..
  30. Scales S, Hesser B, Masuda E, Scheller R. Amisyn, a novel syntaxin-binding protein that may regulate SNARE complex assembly. J Biol Chem. 2002;277:28271-9 pubmed
  31. Li Y, Chin L, Weigel C, Li L. Spring, a novel RING finger protein that regulates synaptic vesicle exocytosis. J Biol Chem. 2001;276:40824-33 pubmed
    ..These results indicate that Spring may act as a regulator of synaptic vesicle exocytosis by controlling the availability of SNAP-25 for the SNARE complex formation. ..
  32. Foley T, Clark A, Stredny E, Wierbowski B. SNAP-25 contains non-acylated thiol pairs that can form intrachain disulfide bonds: possible sites for redox modulation of neurotransmission. Cell Mol Neurobiol. 2012;32:201-8 pubmed publisher
    ..These results provide direct experimental support for the availability, in a subpopulation of SNAP-25, of vicinal thiols that may confer on one or more isoforms of this family of proteins a sensitivity to oxidative stress. ..
  33. Matsuno A, Itoh J, Takekoshi S, Itoh Y, Ohsugi Y, Katayama H, et al. Dynamics of subcellular organelles, growth hormone, Rab3B, SNAP-25, and syntaxin in rat pituitary cells caused by growth hormone releasing hormone and somatostatin. Microsc Res Tech. 2003;62:232-9 pubmed
    ..These results suggest that rab3B plays a principal role in GH secretion in the anterior pituitary cells and that SNAP-25 and syntaxin act as co-workers with rab3B in the functional regulation of GH secretion. ..
  34. Vikman J, Svensson H, Huang Y, Kang Y, Andersson S, Gaisano H, et al. Truncation of SNAP-25 reduces the stimulatory action of cAMP on rapid exocytosis in insulin-secreting cells. Am J Physiol Endocrinol Metab. 2009;297:E452-61 pubmed publisher
    ..Thus we hypothesize that SNAP-25 is a necessary partner in the complex mediating cAMP-enhanced rapid exocytosis in insulin-secreting cells. ..
  35. Cypionka A, Stein A, Hernandez J, Hippchen H, Jahn R, Walla P. Discrimination between docking and fusion of liposomes reconstituted with neuronal SNARE-proteins using FCS. Proc Natl Acad Sci U S A. 2009;106:18575-80 pubmed publisher
    ..Our results show that under appropriate conditions a docked state, mediated by trans-SNARE interactions, can be isolated that constitutes an intermediate in the fusion pathway. ..
  36. Benagiano V, Lorusso L, Flace P, Girolamo F, Rizzi A, Bosco L, et al. VAMP-2, SNAP-25A/B and syntaxin-1 in glutamatergic and GABAergic synapses of the rat cerebellar cortex. BMC Neurosci. 2011;12:118 pubmed publisher
  37. Yang K, Jiang X, Su Q, Wang J, Li C, Xia Y, et al. Disruption of glutamate neurotransmitter transmission is modulated by SNAP-25 in benzo[a]pyrene-induced neurotoxic effects. Toxicology. 2017;384:11-22 pubmed publisher
    ..Our results will provide novel evidence to reveal the possible role of SNAP-25 in B[a]P-induced neurotoxicity and may be helpful for searching the potential strategy for the prevention measures against B[a]P neurotoxicity. ..
  38. Choi U, Strop P, Vrljic M, Chu S, Brunger A, WENINGER K. Single-molecule FRET-derived model of the synaptotagmin 1-SNARE fusion complex. Nat Struct Mol Biol. 2010;17:318-24 pubmed publisher
    ..The loop arrangement is similar to that of the crystal structure of SNARE-induced Ca(2+)-bound Syt3, suggesting a common mechanism by which the interaction between synaptotagmins and SNAREs aids in Ca(2+)-triggered fusion. ..
  39. Park S, Jung Y, Kim Y, Lee Kang J, Lee K. Glucose/oxygen deprivation and reperfusion upregulate SNAREs and complexin in organotypic hippocampal slice cultures. Neuropathology. 2008;28:612-20 pubmed publisher
    ..Our data suggest that alteration of presynaptic function may play a partial role in delayed neuronal death during GOD and reperfusion in organotypic hippocampal slice cultures. ..
  40. Zilly F, Sørensen J, Jahn R, Lang T. Munc18-bound syntaxin readily forms SNARE complexes with synaptobrevin in native plasma membranes. PLoS Biol. 2006;4:e330 pubmed
    ..We conclude that Munc18-1 allows for the formation of a complex between syntaxin and SNAP-25 that serves as an acceptor for vesicle-bound synaptobrevin and that thus represents an intermediate in the pathway towards exocytosis. ..
  41. Tsujimoto S, Pelto Huikko M, Aitola M, Meister B, Vik Mo E, Davanger S, et al. The cellular and developmental expression of hrs-2 in rat. Eur J Neurosci. 1999;11:3047-63 pubmed
    ..The wide distribution, the interaction with SNAP-23 and the localization on multivesicular body membranes suggest a general role for hrs-2 in cellular machinery. ..
  42. Quintanar J, Salinas E. Effect of hypothyroidism on synaptosomal-associated protein of 25 kDa and syntaxin-1 expression in adenohypophyses of rat. J Endocrinol Invest. 2002;25:754-8 pubmed
    ..In conclusion, thyroidectomy produces changes in both expression and immunoreactivity of SNAP-25 and syntaxin-1 in adenohypophyses of rats and these effects can be reversed by T4 administration. ..
  43. Ohara Imaizumi M, Nishiwaki C, Nakamichi Y, Kikuta T, Nagai S, Nagamatsu S. Correlation of syntaxin-1 and SNAP-25 clusters with docking and fusion of insulin granules analysed by total internal reflection fluorescence microscopy. Diabetologia. 2004;47:2200-7 pubmed
    ..There was a close correlation between the number of syntaxin-1 and SNAP-25 clusters and the number of docked insulin granules, which is associated with the fusion of insulin granules. ..
  44. Su Q, Cai Q, Gerwin C, Smith C, Sheng Z. Syntabulin is a microtubule-associated protein implicated in syntaxin transport in neurons. Nat Cell Biol. 2004;6:941-53 pubmed
    ..These findings suggest that syntabulin functions as a linker molecule that attaches syntaxin-cargo vesicles to kinesin I, enabling the transport of syntaxin-1 to neuronal processes. ..
  45. Xu N, Yu Y, Zhu J, Liu H, Shen L, Zeng R, et al. Inhibition of SNAP-25 phosphorylation at Ser187 is involved in chronic morphine-induced down-regulation of SNARE complex formation. J Biol Chem. 2004;279:40601-8 pubmed
  46. Jacobsson G, Piehl F, Bark I, Zhang X, Meister B. Differential subcellular localization of SNAP-25a and SNAP-25b RNA transcripts in spinal motoneurons and plasticity in expression after nerve injury. Brain Res Mol Brain Res. 1996;37:49-62 pubmed
    ..This study shows that, in spinal motoneurons, SNAP-25a and SNAP-25b RNA transcripts have different subcellular localization and that levels of SNAP-25 RNA transcripts are down-regulated after axonal injury. ..
  47. Barakauskas V, Moradian A, Barr A, Beasley C, Rosoklija G, Mann J, et al. Quantitative mass spectrometry reveals changes in SNAP-25 isoforms in schizophrenia. Schizophr Res. 2016;177:44-51 pubmed publisher
    ..This in turn could contribute to the greater interaction between SNAP25 and syntaxin, and possibly disturb neurotransmission in the illness.
  48. Pertsinidis A, Mukherjee K, Sharma M, Pang Z, Park S, Zhang Y, et al. Ultrahigh-resolution imaging reveals formation of neuronal SNARE/Munc18 complexes in situ. Proc Natl Acad Sci U S A. 2013;110:E2812-20 pubmed publisher
    ..Our superresolution imaging method provides a framework for investigating interactions between the synaptic vesicle fusion machinery and other subcellular systems in situ. ..
  49. Schollmeier Y, Krause J, Kreye S, Malsam J, Sollner T. Resolving the function of distinct Munc18-1/SNARE protein interaction modes in a reconstituted membrane fusion assay. J Biol Chem. 2011;286:30582-90 pubmed publisher
    ..These results indicate that Munc18-1 and the neuronal SNAREs already have the inherent capability to function as a basic stage-specific off/on switch to control membrane fusion. ..
  50. Bajohrs M, Darios F, Peak Chew S, Davletov B. Promiscuous interaction of SNAP-25 with all plasma membrane syntaxins in a neuroendocrine cell. Biochem J. 2005;392:283-9 pubmed
  51. Greaves J, Chamberlain L. Differential palmitoylation regulates intracellular patterning of SNAP25. J Cell Sci. 2011;124:1351-60 pubmed publisher
    b>SNAP25 regulates membrane fusion events at the plasma membrane and in the endosomal system, and a functional pool of the protein is delivered to recycling endosomes (REs) and the trans Golgi network (TGN) through an ARF6-dependent cycling ..
  52. Kataoka M, Kuwahara R, Matsuo R, Sekiguchi M, Inokuchi K, Takahashi M. Development- and activity-dependent regulation of SNAP-25 phosphorylation in rat brain. Neurosci Lett. 2006;407:258-62 pubmed
    ..These results clearly indicated that the phosphorylation of SNAP-25 at Ser(187) is regulated in development- and neuronal activity-dependent manners, and is likely to play important roles in higher brain functions. ..
  53. Weiss J, Hüller H, Polack S, Friedrich M, Diedrich K, Treeck O, et al. Estradiol differentially modulates the exocytotic proteins SNAP-25 and munc-18 in pituitary gonadotrophs. J Mol Endocrinol. 2007;38:305-14 pubmed
    ..In conclusion, munc-18 and SNAP-25 were oppositionally influenced by estradiol. The results suggest that estradiol modulates the expression of exocytotic proteins in gonadotrophs and thus affects LH secretion. ..