title: N-glycosylation is essential for vesicular targeting of synaptotagmin 1.
abstract: Synaptotagmins 1 and 7 are candidate Ca(2+) sensors for exocytosis localized to synaptic vesicles and plasma membranes, respectively. We now show that the N-terminal intraluminal sequence of synaptotagmin 1, when transplanted onto synaptotagmin 7, redirects synaptotagmin 7 from the plasma membrane to secretory vesicles. Conversely, mutation of the N-terminal N-glycosylation site of synaptotagmin 1 redirects synaptotagmin 1 from vesicles to the plasma membrane. In cultured hippocampal neurons, the plasma membrane-localized mutant of synaptotagmin 1 suppressed the readily releasable pool of synaptic vesicles, whereas wild-type synaptotagmin 1 did not. In addition to the intraluminal N-glycosylation site, the cytoplasmic C(2) domains of synaptotagmin 1 were required for correct targeting but could be functionally replaced by the C(2) domains of synaptotagmin 7. Our data suggest that the intravesicular N-glycosylation site of synaptotagmin 1 collaborates with its cytoplasmic C(2) domains in directing synaptotagmin 1 to synaptic vesicles via a novel N-glycosylation-dependent mechanism.
authors.affiliation: Center for Basic Neuroscience, Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, 75390, USA.
authors.forename: Weiping
authors.initials: W
authors.lastname: Han
authors.forename: Jeong-Seop
authors.initials: JS
authors.lastname: Rhee
authors.forename: Anton
authors.initials: A
authors.lastname: Maximov
authors.forename: Ye
authors.initials: Y
authors.lastname: Lao
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Mashimo
authors.forename: Christian
authors.initials: C
authors.lastname: Rosenmund
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Südhof
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D005822:Genetic Vectors; D006031:Glycosylation; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009490:Neurosecretory Systems / Q000166:cytology / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism; D016716:PC12 Cells; D017434:Protein Structure, Tertiary; D051381:Rats; D012672:Semliki forest virus / Q000235:genetics; D013572:Synaptic Vesicles / Q000502:physiology*; D050863:Synaptotagmin I; D050857:Synaptotagmins; D014162:Transfection
chemical_list: D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D050863:Synaptotagmin I; C494311:Syt1 protein, mouse; C494312:Syt1 protein, rat; D050857:Synaptotagmins