High impact information on SNC2

• Here we describe the cloning of SNC2 and demonstrate that yeast lacking both SNC genes are deficient in normal bulk secretion, accumulate large numbers of post-Golgi vesicles, and display a variety of conditional lethal phenotypes [1].
• When a 3Q/1R ratio is restored by a mirror R-->Q substitution in the R-SNARE Snc2p, wild-type functionality is observed [2].
• In a screen for suppressors of a temperature-sensitive mutation in the yeast SNAP-25 homolog, Sec9, we have identified a gain-of-function mutation in the yeast synaptobrevin homolog, Snc2 [3].
• The location of the mutations suggests that the C-terminal H2 helical domain of Sec9 is likely to be aligned in parallel with Snc2 in the SNARE complex [3].
• In yeast, the assembly of the target (t)-SNAREs [Tlg2p/Tlg1p,Vti1p] and [Pep12p/Tlg1p,Vti1p] with the vesicular (v)-SNARE Snc2p promotes endocytic fusion [4].

Biological context of SNC2

• Yeast proteins Snc1 and Snc2 localize to secretory vesicles and are required for constitutive exocytosis [5].
• Here, we have used a defined reconstituted fusion assay to determine directly whether syt-t-SNARE interactions couple Ca(2+) to membrane fusion by comparing the effects of Ca(2+)-syt on neuronal (SNAP-25, syntaxin and synaptobrevin) and yeast (Sso1p, Sec9c and Snc2p) SNAREs [6].

Anatomical context of SNC2

• In yeast, homologues of the synaptobrevin/VAMP family of v-SNAREs (Snc1 and Snc2) confer the docking and fusion of secretory vesicles at the cell surface [7].
• In addition, we report that Tlg2p forms a SEC18-dependent SNARE complex with Snc2p, a vesicle SNARE known to function in Golgi to plasma membrane trafficking [8].

Regulatory relationships of SNC2

• We found that the CTM of Snc2p targeted the enhanced cyan fluorescent protein (ECFP)-protein A fusion protein on the cytoplasmic face of the plasma membrane more strongly than that of Ras2p [9].

Other interactions of SNC2

• However, Snc2p binds in vivo to many other syntaxin-like t-SNAREs, and binding of Sncp to the endosomal/Golgi t-SNARE Tlg2p is also reduced in sec4-8 cells [10].
• The C-terminal transmembrane domain (CTM) of Ras2p and Snc2p was examined as the portions with anchoring ability to the cytoplasmic face of the plasma membrane [9].

References