Tomosyn

In biology, tomosyn is a protein with approximately 1,100 amino acids. Two functional domains were originally identified, including one which binds to syntaxin, but recent crystallization of the yeast homolog Sro7 [1] revealed that tomosyn likely has three functional domains: one WD40 domain and one syntaxin-binding domain, as previously recognized, but also another WD40 domain. The study also suggested that tomosyn's 'syntaxin binding domain' is not the reason tomosyn is inhibitory for neurotransmitter release, as originally proposed. Positional cloning [2] suggested that tomosyn might inhibit neurotransmitter secretion in Caenorhabditis elegans neurons. This hypothesis was tested and confirmed [3] , showing that tomosyn specifically inhibits synaptic vesicle priming—the biochemical step immediately preceding vesicle fusion and neurotransmitter release.

References

  1. ↑ Hattendorf DA, Andreeva A, Gangar A, Brennwald PJ, Weis WI (March 2007). "Structure of the yeast polarity protein Sro7 reveals a SNARE regulatory mechanism". Nature. 446 (7135): 567–71. doi:10.1038/nature05635. PMID 17392788.
  2. ↑ Dybbs M, Ngai J, Kaplan JM (July 2005). "Using microarrays to facilitate positional cloning: identification of tomosyn as an inhibitor of neurosecretion". PLoS Genet. 1 (1): 6–16. doi:10.1371/journal.pgen.0010002. PMC 1183521Freely accessible. PMID 16103915.
  3. ↑ Gracheva EO, Burdina AO, Holgado AM, et al. (July 2006). "Tomosyn inhibits synaptic vesicle priming in Caenorhabditis elegans". PLoS Biol. 4 (8): e261. doi:10.1371/journal.pbio.0040261. PMC 1514790Freely accessible. PMID 16895441.


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