| Exocyst complex subunit sec 8 binds to postsynaptic density protein 95 ( PSD 95 ) : a novel interaction regulated by cypin ( cytosolic PSD 95 interactor ) . ^^^ Sec 8 binds to PDZ 1 2 of PSD 95 , and this binding can be competed with a peptide that binds to PDZ 1 and PDZ 2 in the peptide binding site . ^^^ Immunoblotting of rat tissue extracts shows that sec 8 and PSD 95 are enriched in the same brain regions , and sec 8 and PSD 95 have the same subcellular distribution in pheochromocytoma cells , suggesting that these proteins may interact in vivo . ^^^ Immunoprecipitation studies of sec 8 and PSD 95 in brain provide further evidence of a sec 8 and PSD 95 interaction . ^^^ Furthermore , the cytosolic PSD 95 interactor competes with sec 8 for interaction with PSD 95 . ^^^ |