Crystal structure of glycogen synthase kinase 3 beta: structural basis for phosphate-primed substrate specificity and autoinhibition.
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Dajani R, Fraser E, Roe SM, Young N, Good V, Dale TC, Pearl LH
Crystal structure of glycogen synthase kinase 3 beta: structural basis for phosphate-primed substrate specificity and autoinhibition.
Cell. 2001 Jun 15;105(6):721-32.
- PubMed ID
- 11440715 [ View in 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.