| Primary Identifier | IPR043127 | Type | Homologous_superfamily |
| Short Name | Sec-1-like_dom3a |
| description | Members of the Sec1 family include Sec1, Sly1, Slp1/Vps33, Vps45/Stt10 (yeast), Unc-18 (nematode), Munc-18b/muSec1, Munc-18c (mouse), Rop (Drosophila), Munc-18/n-Sec1/rbSec1A and rbSec1B (rat) [].Sec1-like molecules have been implicated in a variety of eukaryotic vesicle transport processes including neurotransmitter release by exocytosis [].They regulate vesicle transport by binding to a t-SNARE from the syntaxin family. This process is thought to prevent SNARE complex formation, a protein complex required for membrane fusion. Whereas Sec1 molecules are essential for neurotransmitter release and other secretory events, their interaction with syntaxin molecules seems to represent a negative regulatory step in secretion []. The nSec1 polypeptide chain can be divided into three domains. The first domain, consists of a five-stranded parallel β-sheet flanked by five α-helices. The second domain, like the first one, has an α-β-alpha fold, however the β-sheet of domain 2 features five parallel strands with an additional antiparallel strand on one edge. The third domain is a large insertion between the third and fourth parallel strands of domain 2, and can be subdivided in two [].This superfamily represents the N-terminal region of domain 3 (called domain 3a) found in Sec1 and related proteins. |
