title: Glycogen synthase kinase-3--an overview of an over-achieving protein kinase.
abstract: Glycogen synthase kinase-3 (GSK-3) has attracted much scrutiny due to its plethora of cellular functions, novel mechanisms of regulation and its potential as a therapeutic target for several common diseases. In mammals, GSK-3 is encoded by two genes, termed GSK-3alpha and GSK-3beta, that yield related but distinct protein-serine kinases. GSK-3 is unusual in that its protein kinase activity tends to be high in resting cells and cellular stimuli, such as hormones and growth factors, result in its catalytic inactivation. Further, many of the substrate proteins of GSK-3 are functionally inhibited by phosphorylation. Thus, signals that inhibit GSK-3 often cause activation of its diverse array of target proteins. Regulation of GSK-3 is important for normal development, regulation of metabolism, neuronal growth and differentiation and modulation of cell death. Dysregulation of GSK-3 activity has been implicated in human pathologies such as neurodegenerative diseases and type-2 diabetes. In this introductory chapter we provide a primer on the modes of GSK-3 regulation and a description of the various signaling pathways and cellular processes in which GSK-3 is an active participant.
authors.affiliation: Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
authors.forename: Lisa
authors.initials: L
authors.lastname: Kockeritz
authors.forename: Bradley
authors.initials: B
authors.lastname: Doble
authors.forename: Satish
authors.initials: S
authors.lastname: Patel
authors.forename: James R
authors.initials: JR
authors.lastname: Woodgett
mesh_terms: D000818:Animals; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000145:classification / Q000502:physiology*; D006801:Humans; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013379:Substrate Specificity / Q000187:drug effects / Q000502:physiology
chemical_list: D047428:Protein Kinase Inhibitors; D038362:Glycogen Synthase Kinase 3