Yeast synaptobrevin homologs are modified posttranslationally by the addition of palmitate.
Yeast possess two homologs of the synaptobrevin family of vesicle-associated membrane proteins that function in membrane recognition and vesicle fusion. Yeast proteins Snc1 and Snc2 localize to secretory vesicles and are required for constitutive exocytosis. They also form a physical complex with a plasma membrane protein, Sec9, which is necessary for vesicle docking and fusion to occur in vivo. Formation of this molecular complex, as a prerequisite for vesicle fusion, appears to have been conserved evolutionarily. Here we demonstrate that Snc proteins undergo a single posttranslational modification with the addition of a palmitate moiety to Cys-95 in Snc1. Modification of Cys-95 (which is located proximal to the transmembrane domain) is rapid, occurs in the endoplasmic reticulum, and is long-lasting. Mutation of Cys-95 to Ser-95 blocks palmitoylation and appears to affect Snc protein stability. This provides evidence that synaptobrevin-like proteins are modified posttranslationally, and we predict that fatty acylation may be common to those found in higher eukaryotes.
Couve
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Department of Cell Biology and Anatomy, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
Protopopov
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Gerst
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JE
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D015870:Gene Expression; D005800:Genes, Fungal; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D009838:Oligodeoxyribonucleotides; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D010641:Phenotype; D011499:Protein Processing, Post-Translational; D050683:R-SNARE Proteins; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D005656:Fungal Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009838:Oligodeoxyribonucleotides; D010169:Palmitic Acids; D050683:R-SNARE Proteins; D011994:Recombinant Proteins; C083241:SNC1 protein, S cerevisiae; C083242:SNC2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D019308:Palmitic Acid