title: Phosphorylation-dependent regulation of cyclin D1 nuclear export and cyclin D1-dependent cellular transformation.
abstract: GSK-3beta-dependent phosphorylation of cyclin D1 at Thr-286 promotes the nuclear-to-cytoplasmic redistribution of cyclin D1 during S phase of the cell cycle, but how phosphorylation regulates redistribution has not been resolved. For example, phosphorylation of nuclear cyclin D1 could increase its rate of nuclear export relative to nuclear import; alternatively, phosphorylation of cytoplasmic cyclin D1 by GSK-3beta could inhibit nuclear import. Here, we report that GSK-3beta-dependent phosphorylation promotes cyclin D1 nuclear export by facilitating the association of cyclin D1 with the nuclear exportin CRM1. D1-T286A, a cyclin D1 mutant that cannot be phosphorylated by GSK-3beta, remains nuclear throughout the cell cycle, a consequence of its reduced binding to CRM1. Constitutive overexpression of the nuclear cyclin D1-T286A in murine fibroblasts results in cellular transformation and promotes tumor growth in immune compromised mice. Thus, removal of cyclin D1 from the nucleus during S phase appears essential for regulated cell division.
authors: Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.
authors: J R
authors: JR
authors: Alt
authors: J L
authors: JL
authors: Cleveland
authors: M
authors: M
authors: Hannink
authors: J A
authors: JA
authors: Diehl
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015197:Carcinogenicity Tests; D002352:Carrier Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D019938:Cyclin D1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005347:Fibroblasts / Q000473:pathology; D038362:Glycogen Synthase Kinase 3; D006801:Humans; D028884:Karyopherins; D008297:Male; D051379:Mice; D016513:Mice, SCID; D010766:Phosphorylation; D018160:Receptors, Cytoplasmic and Nuclear; D016196:S Phase / Q000502:physiology; D013912:Threonine / Q000378:metabolism; D000097606:Exportin 1 Protein
chemical_list: D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002352:Carrier Proteins; D019938:Cyclin D1; D005231:Fatty Acids, Unsaturated; D038362:Glycogen Synthase Kinase 3; D028884:Karyopherins; D018160:Receptors, Cytoplasmic and Nuclear; D013912:Threonine; D000097606:Exportin 1 Protein; C038753:leptomycin B