IDENTIFICATION OF RII-BINDING PROTEINS IN THE MOLLUSK MYTILUS-GALLOPROVINCIALIS

Several proteins with M(r) > 70 kDa from various tissues of the sea mu ssel Mytilus galloprovincialis mere specifically recognized in vitro b y the regulatory subunit (type RII alpha of cAMP-dependent protein kin ase (cAPK) from porcine heart. However, none of these proteins interac ted with the regulatory subunit of cAPK from the mollusc itself. The r esults suggest that, unlike mammalian RII, regulatory subunit from mus sel lacks the specific residues responsible for interaction with R-bin ding proteins. Consequently, the identified molluscan RII alpha-bindin g proteins should play a distinct role from cAPK anchoring.