GLYCOGEN-SYNTHASE FROM RABBIT SKELETAL-MUSCLE - AMINO-ACID-SEQUENCE AT THE SITES PHOSPHORYLATED BY GLYCOGEN-SYNTHASE KINASE-3, AND EXTENSION OF THE N-TERMINAL SEQUENCE CONTAINING THE SITE PHOSPHORYLATED BY PHOSPHORYLASE-KINASE

  • 1 January 1980
    • journal article
    • research article
    • Vol. 107  (2) , 529-537
Abstract
Glycogen synthase kinase-3 phosphorylates 3 serine residues on glycogen synthase (sites 3a, 3b and 3c), which are all located in the same 9-amino-acid segment of the polypeptide chain. The sequence in this region is: Arg-Tyr-Pro-Arg-Pro-Ala-Ser(P)-Val-Pro-Pro-Ser(P)-Pro-Ser-Leu-Ser(P)-Arg-. These serine residues are distinct from the sites phosphorylated preferentially by cAMP-dependent protein kinase (sites 1a and 1b) and phosphorylase kinase (site 2). The N-terminal sequence of glycogen synthase containing the serine residue phosphorylated by phosphorylase kinase was extended. The sequence in this region is: Pro-Leu-Ser-Arg-Thr-Leu-Ser(P)-Val-Ser-Ser-Leu-Pro-Gly-Leu-Glu-Asp-Trp-Glu-Asp-Glu-Phe-Asp-Leu-Glu-Asn-Ser-Val-Leu-Phe-(Asx2,Glx2,Ala2,Val2,Lys)-. The similarity to the N-terminal sequence of phosphorylase is confined to the immediate vicinity of the phosphorylation site (residues 4-15). The relationship of glycogen synthase kinase-3 to glycogen synthase kinases that were described by other laboratories is discussed.