Book ChapterDOI
11 Muscle Glycogen Synthase
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This chapter discusses the structure and activity of muscle glycogen synthase, which is regulated by a phosphorylation–dephosphorylation mechanism and is shown to require MgATP and a further protein and to be stimulated by cyclic adenosine 3′,5′-monoph phosphate (cAMP).Abstract:
Publisher Summary This chapter discusses the structure and activity of muscle glycogen synthase. Glycogen synthase is regulated by a phosphorylation–dephosphorylation mechanism. Following the discovery that glycogen phosphorylase and phosphorylase kinase were activated by phosphorylation, Larner and co-workers found that glycogen synthase could exist in two forms in mammalian skeletal muscle. One possessed little activity without glucose 6-phosphate (G6P), whereas the other was almost fully active in the absence of this allosteric activator. The conversion of glycogen synthase from a G6P-independent to a G6P-dependent form is shown to require MgATP and a further protein and to be stimulated by cyclic adenosine 3′,5′-monophosphate (cAMP). The basis for these effects became clearer following the purification of glycogen synthase to homogeneity, when the enzyme is phosphorylated by cAMP-dependent protein kinase. It was reported in an earlier study that the G6P-dependent form contained ≃6 mol phosphate/86 kDa subunit, and with the subsequent identification of additional glycogen synthase kinases it became clear that glycogen synthase is regulated by multisite phosphorylation.read more
Citations
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Journal ArticleDOI
Selective small molecule inhibitors of glycogen synthase kinase-3 modulate glycogen metabolism and gene transcription.
Matthew P. Coghlan,Ainsley A. Culbert,Darren Cross,Stacey L. Corcoran,John W. Yates,Nigel J. Pearce,Olivier Lars SmithKline Beecham Pharmaceu. Rausch,Gregory J. Murphy,Paul S. Carter,Lynne Roxbee Cox,David Mills,Murray J. B. Brown,David Haigh,Robert W. Ward,Smith David Glynn,Kenneth J. Murray,Alastair D. Reith,Julie C. Holder +17 more
TL;DR: SB-216763 and SB-415286 are novel, potent and selective cell permeable inhibitors of GSK-3 and represent valuable pharmacological tools with which the role of G SKS-3 in cellular signalling can be further elucidated.
Journal ArticleDOI
Determinants of Post-Exercise Glycogen Synthesis During Short-Term Recovery
TL;DR: Suggestions have been made that carbohydrate availability is the main limiting factor for glycogen synthesis when large quantities of glucose are ingested following exercise.
Journal ArticleDOI
Identification of multiple epidermal growth factor-stimulated protein serine/threonine kinases from Swiss 3T3 cells.
TL;DR: Results indicate that at least seven distinct fractions of cytosolic kinase activities are stimulated in Swiss 3T3 cells by EGF, and several of these EGF-stimulated activities were inactivated by protein phosphatases, suggesting that they might be regulated by phosphorylation.
Journal ArticleDOI
Increased glycogen synthase kinase-3 activity in diabetes- and obesity-prone C57BL/6J mice.
TL;DR: The studies suggest an unsuspected link between increased GSK-3 activity and development of insulin resistance and type 2 diabetes in fat tissue of C57BL/6J mice, and implicate G SKS-3 as a potential factor contributing to susceptibility of C 57BL/ 6J mice to diet-induced diabetes.
Journal ArticleDOI
Okadaic acid mimics the action of insulin in stimulating protein kinase activity in isolated adipocytes. The role of protein phosphatase 2a in attenuation of the signal.
Timothy A.J. Haystead,J E Weiel,David W. Litchfield,Y. Tsukitani,Edmond H. Fischer,E G Krebs +5 more
TL;DR: The increased tyrosine phosphorylation accompanying the activation of MBP kinases following okadaic acid treatment suggests a role for PP-2a in events that are mediated by tyrosin phosphorylated, and illustrates several important points concerning regulation ofMBP and S6 peptide kinases.
References
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Book ChapterDOI
Assay of inorganic phosphate, total phosphate and phosphatase
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1,4-Diaminobutane (Putrescine), Spermidine, and Spermine
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TL;DR: No specific mechanism has been firmly established for the action of the polyamines in vivo, however, it is clear that these compounds are physiologically important, and further work is necessary to establish the mechanism of their action.
Journal ArticleDOI
Glycogen Synthase Kinase-3 from Rabbit Skeletal Muscle
TL;DR: This chapter discusses glycogen synthase kinase-3 from rabbit skeletal muscle, which has a second activity that is not shared by any other protein kinase—namely, the ability to activate an enzyme termed the MgATP-dependent protein phosphatase.
Journal ArticleDOI
Insulin stimulates tyrosine phosphorylation of the insulin receptor in a cell-free system
TL;DR: The findings suggest that the elements required for phosphorylation are associated with the plasma membrane of the cell and that specific phosphorylated of the insulin receptor on tyrosine residues can be activated in a solubilized preparation.