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Synaptotagmin is endogenously phosphorylated by Ca 2+ /calmodulin protein kinase II in synaptic vesicles
Author(s) -
Popoli Maurizio
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81496-m
Subject(s) - synaptotagmin 1 , synaptic vesicle , synapsin i , microbiology and biotechnology , synaptotagmin i , vesicle fusion , stx1a , phosphorylation , calmodulin , biochemistry , protein kinase a , exocytosis , protein phosphorylation , biology , chemistry , vesicle , c2 domain , membrane , enzyme
The cytoplasmic domain of synaptotagmin (a synaptic vesicle‐specific protein) has a high degree of homology with the Ca 2+ ‐phospholipid binding domain of protein kinase C. The Ca 2+ ‐phospholipid binding activity of synaptotagmin has been implicated in the docking and fusion of synaptic vesicles with the presynaptic membrane during Ca 2+ ‐induced exocytosis. The protein sequence contains potential phosphorylation sites for various protein kinases which could modulate its binding activity. At present there is no clear evidence that the protein is endogenously phosphorylated in intact vesicles. Here it is reported that phospho‐synaptotagmin was immunoprecipitated from endogenously phosphorylated synaptic vesicles. The conditions used indicate that synaptotagmin, as synapsin I, is phosphorylated by Ca 2+ /calmodulin‐dependent protein kinase II.