title: Retracted: p14ARF induces G2 cell cycle arrest in p53- and p21-deficient cells by down-regulating p34cdc2 kinase activity.
abstract: The human INK4a gene locus encodes two structurally unrelated tumor suppressor proteins, p16(INK4a) and p14(ARF). Although primarily proposed to require a functional p53.Mdm-2 signaling axis, recently p14(ARF) has been implicated in p53-independent cell cycle regulation. Here we show that p14(ARF) preferentially induces a G(2) arrest in tumor cells lacking functional p53 and/or p21. Expression of p14(ARF) impaired mitotic entry and enforced a primarily cytoplasmic localization of p34(cdc2) that was associated with a decrease in p34(cdc2) kinase activity and reduced p34(cdc2) protein expression. A direct physical interaction between p14(ARF) and p34(cdc2) was, nevertheless, ruled out by lack of co-immunoprecipitation. The p14(ARF)-induced depletion of p34(cdc2) was associated with impaired cdc25C phosphatase expression and a prominent shift to inhibitory Tyr-15-phosphorylation in G(2)-arrested cells lacking either p53, p21, or both. Finally, reconstitution of p34(cdc2) using a constitutively active, phosphorylation-deficient p34(cdc2AF) mutant alleviated this p14(ARF)-induced G(2) arrest, thereby allowing cell cycle progression. Taken together, these data indicate that p14(ARF) arrests cells lacking functional p53/p21 in the G(2) phase of the cell cycle by targeting p34(cdc2) kinase. This may represent an important fail-safe mechanism by which p14(ARF) protects p53/p21-deficient cells from unrestrained proliferation.
authors.affiliation: Department of Hematology, Oncology and Tumor Immunology, University Medical Center Charité, Campus Berlin-Buch, D-13125 Berlin-Buch, Germany.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Normand
authors.forename: Philipp G
authors.initials: PG
authors.lastname: Hemmati
authors.forename: Berlinda
authors.initials: B
authors.lastname: Verdoodt
authors.forename: Clarissa
authors.initials: C
authors.lastname: von Haefen
authors.forename: Jana
authors.initials: J
authors.lastname: Wendt
authors.forename: Dilek
authors.initials: D
authors.lastname: Güner
authors.forename: Evelyne
authors.initials: E
authors.lastname: May
authors.forename: Bernd
authors.initials: B
authors.lastname: Dörken
authors.forename: Peter T
authors.initials: PT
authors.lastname: Daniel
mesh_terms: D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21; D015536:Down-Regulation; D016195:G2 Phase; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D010766:Phosphorylation; D025803:Tumor Suppressor Protein p14ARF / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics*; D020687:cdc25 Phosphatases / Q000172:deficiency
chemical_list: C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D025803:Tumor Suppressor Protein p14ARF; D016159:Tumor Suppressor Protein p53; D016203:CDC2 Protein Kinase; C517009:CDC25C protein, human; D020687:cdc25 Phosphatases