RRC ID 49206
Author Fukuda M.
Title Vesicle-associated membrane protein-2/synaptobrevin binding to synaptotagmin I promotes O-glycosylation of synaptotagmin I.
Journal J Biol Chem
Abstract Synaptotagmin I (Syt I), an evolutionarily conserved integral membrane protein of synaptic vesicles, is now known to regulate Ca2+-dependent neurotransmitter release. Syt I protein should undergo several post-translational modifications before maturation and subsequent functioning on synaptic vesicles (e.g. N-glycosylation and fatty acylation in vertebrate Syt I), because the apparent molecular weight of Syt I on synaptic vesicles (mature form, 65,000) was much higher than the calculated molecular weight (47,400) predicted from the cDNA sequences both in vertebrates and invertebrates. Common post-translational modification(s) of Syt I conserved across phylogeny, however, have never been elucidated. In the present study, I discovered that dithreonine residues (Thr-15 and Thr-16) at the intravesicular domain of mouse Syt I are post-translationally modified by a complex form of O-linked sugar (i.e. the addition of sialic acids) in PC12 cells and that the O-glycosylation of Syt I in COS-7 cells depends on the coexpression of vesicle-associated membrane protein-2 (VAMP-2)/synaptobrevin. I also showed that a transmembrane domain of Syt I directly interacts with isolated VAMP-2, but not VAMP-2, in the heterotrimeric SNARE (SNAP receptor) complex (vesicle SNARE, VAMP-2, and two target SNAREs, syntaxin IA and SNAP-25). Since di-Thr or di-Ser residues are often found at the intravesicular domain of invertebrate Syt I, and VAMP-dependent O-glycosylation was also observed in squid Syt expressed in COS-7 cells, I propose that VAMP-dependent O-glycosylation of Syt I is a common modification during evolution and may have important role(s) in synaptic vesicle trafficking.
Volume 277(33)
Pages 30351-8
Published 2002-8-16
DOI 10.1074/jbc.M204056200
PII M204056200
PMID 12048209
MeSH Amino Acid Sequence Animals Base Sequence COS Cells Calcium-Binding Proteins* DNA Primers Glycosylation Membrane Glycoproteins / chemistry Membrane Glycoproteins / genetics Membrane Glycoproteins / metabolism* Membrane Proteins / metabolism* Molecular Sequence Data Mutagenesis, Site-Directed Nerve Tissue Proteins / chemistry Nerve Tissue Proteins / genetics Nerve Tissue Proteins / metabolism* Protein Binding Protein Processing, Post-Translational Protein Transport R-SNARE Proteins Sequence Homology, Amino Acid Synaptotagmin I Synaptotagmins
IF 4.106
Times Cited 40
DNA material pEF-FLAG-mouse syntaxin-1a (RDB15166) pEF-FLAG-mouse VAMP-2 (RDB15171) pEF-FLAG-mouse SNAP-25 (RDB15176).