DIFFERENTIAL EXPRESSION OF ISOFORMS OF PSD-95 BINDING-PROTEIN (GKAP SAPAP1) DURING RAT-BRAIN DEVELOPMENT/

PSD-95/SAP90, which binds to the C-terminus of NMDA receptor and Shake r-type potassium channel, is one of the major postsynaptic density pro teins, Recently, novel classes of proteins interacting with the guanyl ate kinase domain of PSD-95 have been identified, guanylate kinase-ass ociated protein (GKAP) and SAP90/PSD-95-associated proteins (SAPAPs). Here we report the isolation of new isoforms of PSD-95 binding protein (GKAP/SAPAP1) using the yeast two-hybrid system. The isolated protein directly interacts with the guanylate kinase domain of PSD-95, Northe rn blot analyses revealed that the expression of these isoforms contai ning distinct N-terminal sequences is differentially regulated during brain development, The present findings suggest that each isoform of t he PSD-95 binding protein is differentially expressed in a development -dependent manner and may be involved in the complex formation of PSD- 95 and channel/receptors at the postsynaptic density. (C) 1997 Federat ion of European Biochemical Societies.