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Calcium Binds Dynamin I and Inhibits Its GTPase Activity
Author(s) -
Liu JunPing,
Zhang QunXing,
Baldwin Graham,
Robinson Phillip J.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66052074.x
Subject(s) - dynamin , gtpase , microbiology and biotechnology , synaptic vesicle , endocytosis , phosphorylation , synaptic vesicle recycling , biology , biochemistry , chemistry , biophysics , vesicle , membrane , receptor
Synaptic vesicle recycling is a neuronal specialization of endocytosis that requires the GTPase activity of dynamin I and is triggered by membrane depolarization and Ca 2+ entry. To establish the relationship between dynamin I GTPase activity and Ca 2+ , we used purified dynamin I and analyzed its interaction with Ca 2+ in vitro. We report that Ca 2+ bound to dynamin I and this was abolished by deletion of dynamin's C‐terminal tail. Phosphorylation of dynamin I by protein kinase C promoted formation of a dynamin I tetramer and increased Ca 2+ binding to the protein. Moreover, Ca 2+ inhibited dynamin I GTPase activity after stimulation by phosphorylation or by phospholipids but not after stimulation with a GST‐SH3 fusion protein containing the SH3 domain of phosphoinositide 3‐kinase. These results suggest that in resting nerve terminals, phosphorylation of dynamin I by protein kinase C converts it to a tetramer that functions as a Ca 2+ ‐sensing protein. By binding to Ca 2+ , dynamin I GTPase activity is specifically decreased, possibly to regulate synaptic vesicle recycling.