Phosphorylation and inactivation of rabbit skeletal muscle glycogen synthase: distinction between kinase Fa-, phosphorylase kinase-, and glycogen synthase (casein) kinase-1-catalyzed reactions.
Rabbit skeletal muscle glycogen synthase was phosphorylated by kinase Fa, phosphorylase kinase, and cAMP-independent synthase (casein) kinase-1 to determine the differences among these kinase-catalyzed reactions. The stoichiometry of phosphate incorporation, the extent of inactivation, and the sites of phosphorylation were compared. Synthase (casein) kinase-1 catalyzes the highest level of synthase phosphorylation (4 mol/subunit) and inactivation (reduction of the activity ratio to below 0.05). The sites, defined by characteristic tryptic peptides, phosphorylated by synthase (casein) kinase-1 are distinguishable from those by kinase Fa and phosphorylase kinase. In addition, synthase (casein) kinase-1, unlike kinase Fa, does not activate ATP X Mg2+-dependent protein phosphatase. These results demonstrate that synthase (casein) kinase-1 is a distinct glycogen synthase kinase.
D000818:Animals; D001665:Binding Sites; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002384:Catalysis; D006006:Glycogen Synthase / Q000378:metabolism*; D038341:Glycogen Synthase Kinases; D007525:Isoelectric Focusing; D009132:Muscles / Q000201:enzymology*; D010764:Phosphorylase Kinase / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000145:classification* / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011817:Rabbits
D006006:Glycogen Synthase; D010770:Phosphotransferases; D011494:Protein Kinases; D010764:Phosphorylase Kinase; D038341:Glycogen Synthase Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases