three of the kinases ( myosin light chain kinase , phosphorylase kinase , and camp-dependent protein kinase ) phosphorylate serine residues , the fourth ( casein-kinase-2 ) mainly threonine , and the fifth ( glycogen synthase ( casein ) kinase-1 ) both serine and threonine .
C0031727
kinases
C0027120
myosin light chain