The Croonian Lecture 1998. Identification of a protein kinase cascade of major importance in insulin signal transduction.
Diabetes affects 3% of the European population and 140 million people worldwide, and is largely a disease of insulin resistance in which the tissues fail to respond to this hormone. This emphasizes the importance of understanding how insulin signals to the cell's interior. We have recently dissected a protein kinase cascade that is triggered by the formation of the insulin 'second messenger' phosphatidylinositide (3,4,5) trisphosphate (PtdIns (3,4,5)P3) and which appears to mediate many of the metabolic actions of this hormone. The first enzyme in the cascade is termed 3-phosphoinositide-dependent protein kinase-1 (PDK1), because it only activates protein kinase B (PKB), the next enzyme in the pathway, in the presence of PtdIns (3,4,5)P3. PKB then inactivates glycogen synthase kinase-3 (GSK3). PDK1, PKB and GSK3 regulate many physiological events by phosphorylating a variety of intracellular proteins. In addition, PKB plays an important role in mediating protection against apoptosis by survival factors, such as insulin-like growth factor-1.
Cohen
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Department of Biochemistry, University of Dundee, UK.
D064413:3-Phosphoinositide-Dependent Protein Kinases; D000595:Amino Acid Sequence; D017209:Apoptosis; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D003920:Diabetes Mellitus / Q000188:drug therapy / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D006003:Glycogen / Q000096:biosynthesis; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008969:Molecular Sequence Data; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D011972:Receptor, Insulin / Q000378:metabolism; D015398:Signal Transduction
D004791:Enzyme Inhibitors; D007328:Insulin; D018129:Phosphatidylinositol Phosphates; D011506:Proteins; D011518:Proto-Oncogene Proteins; C060974:phosphatidylinositol 3,4,5-triphosphate; D006003:Glycogen; D011972:Receptor, Insulin; D038341:Glycogen Synthase Kinases; D064413:3-Phosphoinositide-Dependent Protein Kinases; C578562:PDPK1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3