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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.

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

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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Categories: Homo sapiens | Non-specific serine/threonine protein kinase | Dajani, R. | Pearl, L H. | Roe, S M. | Insulin pathway | Kinase