Munc-18
Munc-18 (an acronym for mammalian uncoordinated-18) protein is the mammalian homologue of the unc-18 protein (which can be found in organisms such as the C. elegans) and is a member of the Sec1/Munc18-like (SM) protein family. Munc-18 has been identified as an essential component of the synaptic vesicle fusion protein complex and and crucial for the regulated exocytosis of neurons and neuroendocrine cells.[1]
Function
Munc-18 binds syntaxin and forms a syntaxin/munc-18 complex which is thought to precede and/or regulate the formation of vesicle docking, a process mediated by VAMP, SNAP-25 and syntaxin.[2] Munc18-1, a member of the SM family, directly promotes syntaxin stability and either controls the spatially correct assembly of core complexes for SNARE-dependent fusion, or acts as a direct component of the fusion machinery itself. Deletion of munc18-1 leads to a defect in secretory vesicle docking.[3] Furthermore, the munc18-1 deficient mouse is the first mouse model wherein neurotransmitter secretion is completely absent. This mouse model is appropriately titled the "silent mouse."[4]
Family members
The following is a list of human munc-18 proteins:
| protein | gene | |
|---|---|---|
| symbol | name | |
| MUNC18-1 | STXBP1 | syntaxin binding protein 1 |
| MUNC18-2 | STXBP2 | syntaxin binding protein 2 |
| MUNC18-3 | STXBP3 | syntaxin binding protein 3 |
| MUNC18-4 | STXBP4 | syntaxin binding protein 4 |
| MUNC18-5 | STXBP5 | syntaxin binding protein 5 |
| MUNC18-6 | STXBP6 | syntaxin binding protein 6 |
See also
References
- ^ Zilly FE, Sørensen JB, Jahn R, Lang T (2006). "Munc18-bound syntaxin readily forms SNARE complexes with synaptobrevin in native plasma membranes". PLoS Biol. 4 (10): e330. doi:10.1371/journal.pbio.0040330. PMC 1570500. PMID 17002520.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Pevsner J, Hsu SC, Braun JE, Calakos N, Ting AE, Bennett MK, Scheller RH (1994). "Specificity and regulation of a synaptic vesicle docking complex". Neuron. 13 (2): 353–61. PMID 8060616.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Toonen RF, de Vries KJ, Zalm R, Südhof TC, Verhage M (2005). "Munc18-1 stabilizes syntaxin 1, but is not essential for syntaxin 1 targeting and SNARE complex formation". J. Neurochem. 93 (6): 1393–400. doi:10.1111/j.1471-4159.2005.03128.x. PMID 15935055.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ http://www.eni-net.org/organization/members/prof-matthijs-verhage/