title: Role of the SUMO-interacting motif in HIPK2 targeting to the PML nuclear bodies and regulation of p53.
abstract: Homeodomain-interacting protein kinase 2 (HIPK2) is a key regulator of various transcription factors including p53 and CtBP in the DNA damage signaling pathway. PML-nuclear body (NB) is required for HIPK2-mediated p53 phosphorylation at Ser46 and induction of apoptosis. Although PML-NB targeting of HIPK2 has been shown, much is not clear about the molecular mechanism of HIPK2 recruitment to PML-NBs. Here we show that HIPK2 colocalizes specifically with PML-I and PML-IV. Mutational analysis showed that HIPK2 recruitment to PML-IV-NBs is mediated by the SUMO-interaction motifs (SIMs) of both PML-IV and HIPK2. Wild-type HIPK2 associated with SUMO-conjugated PML-IV at a higher affinity than with un-conjugated PML-IV, while the association of a HIPK2 SIM mutant with SUMO-modified PML-IV was impaired. In colony formation assays, HIPK2 strongly suppressed cell proliferation, but HIPK2 SIM mutants did not. In addition, activation and phosphorylation of p53 at the Ser46 residue were impaired by HIPK2 SIM mutants. These results suggest that SIM-mediated HIPK2 targeting to PML-NBs is crucial for HIPK2-mediated p53 activation and induction of apoptosis.
authors.affiliation: Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Ki Sa
authors.initials: KS
authors.lastname: Sung
authors.forename: Yun-Ah
authors.initials: YA
authors.lastname: Lee
authors.forename: Eui Tae
authors.initials: ET
authors.lastname: Kim
authors.forename: Seung-Rock
authors.initials: SR
authors.lastname: Lee
authors.forename: Jin-Hyun
authors.initials: JH
authors.lastname: Ahn
authors.forename: Cheol Yong
authors.initials: CY
authors.lastname: Choi
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D000071156:Promyelocytic Leukemia Protein; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C070576:PML protein, human; C115114:HIPK2 protein, human; D017346:Protein Serine-Threonine Kinases