Transducin-mediated, isoform-specific interaction of recombinant rat nucleoside diphosphate kinases with bleached bovine retinal rod outer segment membranes.

The properties of the binding of recombinant rat nucleoside diphosphate (NDP) kinase isoforms alpha and beta (NDP kinase alpha and beta, respectively) to bleached bovine retinal rod outer segment (ROS) membranes were investigated. It was found that: (1) both NDP kinase isoforms interacted with ROS membranes in a pH-, cation- and GTPgammaS-dependent manner; (2) the retinal G-protein transducin was an obligatory factor for the interaction; (3) the apparent affinity of NDP kinase alpha for ROS membranes was about 100-fold higher than that of NDP kinase beta; and (4) an alpha-isoform-specific peptide, corresponding to the sequence of the N-terminal third (variable region), had the ability to displace bovine NDP kinase from ROS membranes. The results suggest the possible involvement of NDP kinases in cellular regulation via interaction with G-proteins and provide a structural basis for the possible differential roles of mammalian NDP kinase isoforms in the cell.