title: Adhesion-dependent cell cycle progression linked to the expression of cyclin D1, activation of cyclin E-cdk2, and phosphorylation of the retinoblastoma protein.
abstract: Growth factors and cell anchorage jointly regulate transit through G1 in almost all cell types, but the cell cycle basis for this combined requirement remains largely uncharacterized. We show here that cell adhesion and growth factors jointly regulate the cyclin D1- and E-dependent kinases. Adhesion to substratum regulates both the induction and translation of cyclin D1 mRNA. Nonadherent cells fail to phosphorylate the retinoblastoma protein (Rb), and enforced expression of cyclin D1 rescues Rb phosphorylation and entry into S phase when G1 cells are cultured in the absence of substratum. Nonadherent cells also fail to activate the cyclin E-associated kinase, and this effect can be linked to an increased association of the cdk inhibitors, p21 and p27. These data describe a striking convergence in the cell cycle controls used by the two major signal transduction systems responsible for normal and abnormal cell growth. Taken together with our previous studies showing adhesion-dependent expression of cyclin A, they also establish the cell cycle basis for explaining the combined requirement for growth factors and the extracellular matrix in transit through the Rb checkpoint, entry into S phase, and anchorage-dependent growth.
authors.affiliation: Department of Cell Biology and Anatomy, University of Miami School of Medicine, FL 33101, USA.
authors.forename: X
authors.initials: X
authors.lastname: Zhu
authors.forename: M
authors.initials: M
authors.lastname: Ohtsubo
authors.forename: R M
authors.initials: RM
authors.lastname: Böhmer
authors.forename: J M
authors.initials: JM
authors.lastname: Roberts
authors.forename: R K
authors.initials: RK
authors.lastname: Assoian
mesh_terms: D016475:3T3 Cells; D000818:Animals; D042846:CDC2-CDC28 Kinases; D002448:Cell Adhesion / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins; D019938:Cyclin D1; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016213:Cyclins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004791:Enzyme Inhibitors; D005347:Fibroblasts / Q000166:cytology; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000378:metabolism; D008934:Mitogens / Q000494:pharmacology; D015513:Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011506:Proteins; D012333:RNA, Messenger / Q000032:analysis; D016160:Retinoblastoma Protein / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; D008934:Mitogens; D015513:Oncogene Proteins; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D025521:Tumor Suppressor Proteins; D019938:Cyclin D1; D050760:Cyclin-Dependent Kinase Inhibitor p27; D003513:Cycloheximide; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases