title: Pdk1 activity controls proliferation, survival, and growth of developing pancreatic cells.
abstract: The formation of adequate masses of endocrine and exocrine pancreatic tissues during embryogenesis is essential to ensure proper nutrition and glucose homeostasis at postnatal stages. We generated mice with pancreas-specific ablation of the 3-phosphoinositide-dependent protein kinase 1 (Pdk1) to investigate how signaling downstream of the phosphatidylinositol-3-OH kinase (PI3K) pathway controls pancreas development. Pdk1-conditional knock-out mice were born with conspicuous pancreas hypoplasia, and within a few weeks, they developed severe hyperglycemia. Our detailed characterization of the mutant embryonic pancreas also revealed distinct temporal, cell type-specific requirements of Pdk1 activity in the control of cell proliferation, cell survival, and cell size during pancreas development. These results thus uncover Pdk1 as a novel, crucial regulator of pancreatic growth during embryogenesis. In addition, we provide evidence that Pdk1 activity is required differently in mature pancreatic cell types, since compensatory proliferation and possible mTORC2 activation occurred in exocrine cells but not in beta cells of the Pdk1-deficient postnatal pancreas.
authors.affiliation: Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Joby J
authors.initials: JJ
authors.lastname: Westmoreland
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Mohamed
authors.initials: M
authors.lastname: Bouzaffour
authors.forename: Suzanne J
authors.initials: SJ
authors.lastname: Baker
authors.forename: Beatriz
authors.initials: B
authors.lastname: Sosa-Pineda
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D048429:Cell Size; D002470:Cell Survival; D004622:Embryo, Mammalian / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism; D051379:Mice; D010179:Pancreas / Q000254:growth & development*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D015398:Signal Transduction
chemical_list: C000631433:Pdk1 protein, mouse; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D017346:Protein Serine-Threonine Kinases