Yeast syntaxins Sso1p and Sso2p belong to a family of related membrane proteins that function in vesicular transport.
The yeast SEC1 gene encodes a hydrophilic protein that functions at the terminal stage in secretion. We have cloned two yeast genes, SSO1 and SSO2, which in high copy number can suppress sec1 mutations and also mutations in several other late acting SEC genes, such as SEC3, SEC5, SEC9 and SEC15. SSO1 and SSO2 encode small proteins with N-terminal hydrophilic domains and C-terminal hydrophobic tails. The two proteins are 72% identical in sequence and together perform an essential function late in secretion. Sso1p and Sso2p show significant sequence similarity to six other proteins. Two of these, Sed5p and Pep12p, are yeast proteins that function in transport from ER to Golgi and from Golgi to the vacuole, respectively. Also related to Sso1p and Sso2p are three mammalian proteins: epimorphin, syntaxin A/HPC-1 and syntaxin B. A nematode cDNA product also belongs to the new protein family. The new protein family is thus present in a wide variety of eukaryotic cells, where its members function at different stages in vesicular transport.
Aalto
M K
MK
VTT Biotechnical Laboratory, Espoo, Finland.
Ronne
H
H
Keränen
S
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D000595:Amino Acid Sequence; D000954:Antigens, Surface / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D001692:Biological Transport; D002451:Cell Compartmentation; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics*; D019204:GTP-Binding Proteins / Q000235:genetics; D005800:Genes, Fungal; D016153:Genes, Suppressor; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D008565:Membrane Proteins / Q000235:genetics*; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics*; D050765:Qa-SNARE Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins
D000954:Antigens, Surface; D005656:Fungal Proteins; D008565:Membrane Proteins; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; C497931:SEC1 protein, S cerevisiae; C060862:SEC15 protein, S cerevisiae; C084006:SSO1 protein, S cerevisiae; C084007:SSO2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins; D019204:GTP-Binding Proteins