Calcium Binds Dynamin I and Inhibits Its GTPase Activity
Article first published online: 23 NOV 2002
Journal of Neurochemistry
Volume 66, Issue 5, pages 2074–2081, May 1996
How to Cite
Liu, J.-P., Zhang, Q.-X., Baldwin, G. and Robinson, P. J. (1996), Calcium Binds Dynamin I and Inhibits Its GTPase Activity. Journal of Neurochemistry, 66: 2074–2081. doi: 10.1046/j.1471-4159.1996.66052074.x
- Issue published online: 23 NOV 2002
- Article first published online: 23 NOV 2002
- Received September 5, 1995; revised manuscript received November 27, 1995; accepted December 4, 1995.
- Protein kinase C;
- Synaptic vesicle recycling;
Abstract: Synaptic vesicle recycling is a neuronal specialization of endocytosis that requires the GTPase activity of dynamin I and is triggered by membrane depolarization and Ca2+ entry. To establish the relationship between dynamin I GTPase activity and Ca2+, we used purified dynamin I and analyzed its interaction with Ca2+ in vitro. We report that Ca2+ 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 Ca2+ binding to the protein. Moreover, Ca2+ 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 Ca2+-sensing protein. By binding to Ca2+, dynamin I GTPase activity is specifically decreased, possibly to regulate synaptic vesicle recycling.