Identification of PSD-93 as a substrate for the Src family tyrosine kinase Fyn

Nada, S., Shima, T., Yanai, H., Husi, H., Grant, S. G.N., Okada, M. and Akiyama, T. (2003) Identification of PSD-93 as a substrate for the Src family tyrosine kinase Fyn. Journal of Biological Chemistry, 278(48), pp. 47610-47621. (doi: 10.1074/jbc.M303873200) (PMID:13129934)

Abstract

In order to study the role of tyrosine kinase signaling in the post-synaptic density (PSD), tyrosine-phosphorylated proteins associated with the PSD-95/NMDA receptor complex were analyzed. The NMDA receptor complex from the mouse brain was successfully solubilized with deoxycholate and immunopurified with anti-PSD-95 or anti-phosphotyrosine antibody. Immunoblot analyses revealed that the predominantly tyrosine-phosphorylated proteins in the NMDA receptor complex are the NR2A/B subunits and a novel 120 kDa protein. Purification and microsequencing analysis showed that the 120 kDa protein is mouse PSD-93/Chapsyn-110. Recombinant PSD-93 was phosphorylated by Fyn in vitro, and Tyr-384 was identified as a major phosphorylation site. Tyrosine phosphorylation of PSD-93 was greatly reduced in brain tissue from Fyn-deficient mice compared with wild-type mice. Furthermore, an N-terminal palmitoylation signal of PSD-93 was found to be essential for its anchoring to the membrane, where Fyn is also localized. In COS7 cells, exogenously expressed PSD-93 was phosphorylated, dependent on its membrane localization. In addition, tyrosine-phosphorylated PSD-93 was able to bind to Csk, a negative regulator of Src family kinases, in vitro as well as in a brain lysate. These results suggest that PSD-93 serves as a membrane-anchored substrate of Fyn and plays a role in the regulation of Fyn-mediated modification of NMDA receptor function.

• Item Type: Articles (Other)
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Husi, Dr Holger
• Authors: Nada, S., Shima, T., Yanai, H., Husi, H., Grant, S. G.N., Okada, M., and Akiyama, T.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Journal of Biological Chemistry
• Publisher: American Society for Biochemistry and Molecular Biology, Inc.
• ISSN: 0021-9258
• ISSN (Online): 1083-351X