| In this report , we identify phosducin and PhLP as novel GRK 2 substrates . ^^^ The phosphorylation of purified phosducin and PhLP by recombinant GRK 2 proceeds rapidly and stoichiometrically ( 0 . 82 + / 0 . 1 and 0 . 83 + / 0 . 09 mol of P ( 1 ) / mol of protein , respectively ) . ^^^ Analysis of GRK 2 phosphorylation of a variety of deletion mutants of phosducin and PhLP indicates that the critical region for GRK 2 phosphorylation is localized in the C terminal domain of both phosducin and PhLP ( between residues 204 and 245 and 195 and 218 , respectively ) . ^^^ The identification of phosducin and PhLP as new substrates for GRK 2 further expands the cellular roles of this kinase and suggests new mechanisms for modulating GPCR signal transduction . . ^^^ Phosphorylation of phosducin and phosducin like protein by G protein coupled receptor kinase 2 . ^^^ |