Crystal Structure of Glycogen Synthase Kinase 3Beta . Structural Basis for Phosphate-Primed Substrate Specificity and AutoinhibitionDajani, R., Fraser, E., Roe, S.M., Young, N., Good, V., Dale, T.C., Pearl, L.H.
(2001) Cell 105: 721
- PubMed: 11440715
- DOI: https://doi.org/10.1016/s0092-8674(01)00374-9
- Primary Citation of Related Structures:
- PubMed Abstract:
Glycogen synthase kinase 3 beta (GSK3 beta) plays a key role in insulin and Wnt signaling, phosphorylating downstream targets by default, and becoming inhibited following the extracellular signaling event. The crystal structure of human GSK3 beta shows a catalytically active conformation in the absence of activation-segment phosphorylation, with the sulphonate of a buffer molecule bridging the activation-segment and N-terminal domain in the same way as the phosphate group of the activation-segment phospho-Ser/Thr in other kinases. The location of this oxyanion binding site in the substrate binding cleft indicates direct coupling of P+4 phosphate-primed substrate binding and catalytic activation, explains the ability of GSK3 beta to processively hyperphosphorylate substrates with Ser/Thr pentad-repeats, and suggests a mechanism for autoinhibition in which the phosphorylated N terminus binds as a competitive pseudosubstrate with phospho-Ser 9 occupying the P+4 site.
Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, London SW3 6JB, United Kingdom.