Inhibitory effect of NAP-22 on the phosphatase activity of synaptojanin-1
Article first published online: 19 SEP 2011
Copyright © 2011 Wiley Periodicals, Inc.
Journal of Neuroscience Research
Volume 90, Issue 1, pages 21–27, January 2012
How to Cite
Takaichi, R., Odagaki, S.-I., Kumanogoh, H., Nakamura, S., Morita, M. and Maekawa, S. (2012), Inhibitory effect of NAP-22 on the phosphatase activity of synaptojanin-1. J. Neurosci. Res., 90: 21–27. doi: 10.1002/jnr.22740
- Issue published online: 15 NOV 2011
- Article first published online: 19 SEP 2011
- Manuscript Accepted: 20 JUN 2011
- Manuscript Revised: 27 MAY 2011
- Manuscript Received: 10 APR 2011
- synaptic vesicle;
- lipid raft;
- clathrin-coated vesicle
Endocytosis of the synaptic vesicle is a complicated process, in which many proteins and lipids participate. Phosphatidylinositol 4,5-bisphosphate (PIP2) plays important roles in the process, and the dynamic regulation of this lipid is one of the key events. Synaptojanin is a PIP2 phosphatase, and dephosphorylation of PIP2 of the clathrin coated-vesicle results in the uncoating of the vesicle. NAP-22 is one of the major proteins of the neuronal detergent-resistant membrane microdomain and localizes in both the presynaptic plasma membrane and the synaptic vesicle. To elucidate the role of NAP-22 in synaptic function, a screening of the NAP-22 binding proteins through pull-down assay was performed. In addition to CapZ protein, synaptojanin-1 was detected by LC-MS/MS, and Western blotting using antisynaptojanin-1 confirmed this result. The interaction seems to be important in the course of synaptic vesicle endocytosis, because NAP-22 inhibited the phosphatase activity of synaptojanin in a dose-dependent manner. The inhibitory region for 5-phosphatase and the binding region for PIP2 overlapped in the amino acid sequence of NAP-22, so elucidation of the regulatory mechanism of the PIP2 binding ability of NAP-22 could be important in understanding the membrane dynamics at the presynaptic region. © 2011 Wiley Periodicals, Inc.