using a peptide based on the glycogen synthase sequence prpas ( 3a ) vpps ( 3b ) psls ( 3c ) rhss ( 4 ) phqs ( 5 ) edeeep ( where the numbers in parentheses denote sites of phosphorylation ) , we showed previously that phosphorylation of site 5 by casein kinase ii was necessary for gsk-3 to phosphorylate the peptide at sites 3a , 3b , 3c , and 4 ( fiol , c. j. , mahrenholz , a. m. , wang , y. , roeske , r. w. , and roach , p. j . ( 1987 ) j. biol . chem . 262 , 14042-14048 ) .
C0031715
phosphorylation
C0244989
gsk-3