Tyrosine kinase and tyrosine phosphatase participate in regulation of interactions of NMDA receptor subunit 2A with Src and Fyn mediated by PSD-95 after transient brain ischemia

In this study, we investigated the effects of protein tyrosine kinase (PTK) and protein tyrosine phosphatase (PTP) on the tyrosine phosphorylation of N-methyl-D-aspartate receptor subunit 2A (NR2A) and the interactions among NR2A, postsynaptic density protein 95 (PSD-95), Fyn/Src after brain ischemia/reperfusion (I/R). The following results were observed: (1) the increase in tyrosine phosphorylation of NR2A induced by I/R was suppressed by genistein, an inhibitor of PTK, but was further enhanced by sodium orthovanadate, an inhibitor of PTP, which were administered to the SD rats 20 min before ischemia. (2) Importantly, genistein and sodium orthovanadate increased and decreased the interactions involving NR2A, PSD-95, Fyn and Src, respectively. These results demonstrated that PTK and PTP were involved in regulating tyrosine phosphorylation of NR2A through changing the interaction among NR2A, PSD-95, Fyn/Src. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.