the glycogen-binding ( g ) subunit of protein phosphatase-1g is phosphorylated stoichiometrically by glycogen synthase kinase-3 ( gsk3 ) , and with a greater catalytic efficiency than glycogen synthase , but only after prior phosphorylation by cyclic amp-dependent protein kinase ( a-kinase ) at site 1 .
C0031715
phosphorylation
C0031727
kinase