Ubiquitination and Degradation of Homeodomain-interacting Protein Kinase 2 by WD40 Repeat/SOCS Box Protein WSB-1

Abstract

Homeodomain-interacting protein kinase 2 (HIPK2) is a member of the nuclear protein kinase family, which induces both p53- and CtBP-mediated apoptosis. Levels of HIPK2 were increased by UV irradiation and cisplatin treatment, thereby implying the degradation of HIPK2 in cells under normal conditions. Here, we indicate that HIPK2 is ubiquitinated and degraded by the WD40-repeat/SOCS box protein WSB-1, a process that is blocked under DNA damage conditions. Yeast two-hybrid screening was conducted to identify the proteins that interact with HIPK2. WSB-1, an E3 ubiquitin ligase, was characterized as an HIPK2-interacting protein. The coexpression of WSB-1 resulted in the degradation of HIPK2 via its C-terminal region. Domain analysis of WSB-1 showed that WD40-repeats and the SOCS box were required for its interaction with and degradation of HIPK2, respectively. In support of the degradation of HIPK2 by WSB-1, HIPK2 was polyubiquitinated by WSB-1 in vitro and in vivo. The knockdown of endogenous WSB-1 with the expression of short hairpin RNA against WSB-1 increases the stability of endogenous HIPK2 and resulted in the accumulation of HIPK2. The ubiquitination and degradation of HIPK2 by WSB-1 was inhibited completely via the administration of DNA damage reagents, including Adriamycin and cisplatin. These findings effectively illustrate the regulatory mechanisms by which HIPK2 is maintained at a low level, by WSB-1 in cells under normal conditions, and stabilized by genotoxic stresses. Homeodomain-interacting protein kinase 2 (HIPK2) is a member of the nuclear protein kinase family, which induces both p53- and CtBP-mediated apoptosis. Levels of HIPK2 were increased by UV irradiation and cisplatin treatment, thereby implying the degradation of HIPK2 in cells under normal conditions. Here, we indicate that HIPK2 is ubiquitinated and degraded by the WD40-repeat/SOCS box protein WSB-1, a process that is blocked under DNA damage conditions. Yeast two-hybrid screening was conducted to identify the proteins that interact with HIPK2. WSB-1, an E3 ubiquitin ligase, was characterized as an HIPK2-interacting protein. The coexpression of WSB-1 resulted in the degradation of HIPK2 via its C-terminal region. Domain analysis of WSB-1 showed that WD40-repeats and the SOCS box were required for its interaction with and degradation of HIPK2, respectively. In support of the degradation of HIPK2 by WSB-1, HIPK2 was polyubiquitinated by WSB-1 in vitro and in vivo. The knockdown of endogenous WSB-1 with the expression of short hairpin RNA against WSB-1 increases the stability of endogenous HIPK2 and resulted in the accumulation of HIPK2. The ubiquitination and degradation of HIPK2 by WSB-1 was inhibited completely via the administration of DNA damage reagents, including Adriamycin and cisplatin. These findings effectively illustrate the regulatory mechanisms by which HIPK2 is maintained at a low level, by WSB-1 in cells under normal conditions, and stabilized by genotoxic stresses. Homeodomain-interacting protein kinase 2 (HIPK2) 5The abbreviations used are: HIPK2homeodomain-interacting protein kinase 2SCFSkp1-Cullin-F-boxECSElonginB/C-Cul2/5-SOCSSOCS boxsuppressor of cytokine signaling boxGFPgreen fluorescent proteinMyc tagMyc epitope tagGSTglutathione S-transferaseUbubiquitinE1ubiquitin-activating enzymeE2ubiquitin-conjugating enzymeE3ubiquitin ligaseaaamino acid(s)HAhemagglutininshRNAshort hairpin RNA. 5The abbreviations used are: HIPK2homeodomain-interacting protein kinase 2SCFSkp1-Cullin-F-boxECSElonginB/C-Cul2/5-SOCSSOCS boxsuppressor of cytokine signaling boxGFPgreen fluorescent proteinMyc tagMyc epitope tagGSTglutathione S-transferaseUbubiquitinE1ubiquitin-activating enzymeE2ubiquitin-conjugating enzymeE3ubiquitin ligaseaaamino acid(s)HAhemagglutininshRNAshort hairpin RNA. is a member of a novel family of nuclear protein kinases and is well conserved from Drosophila to humans (1Choi C.Y. Kim Y.H. Kim Y.O. Park S.J. Kim E.A. Riemenschneider W. Gajewski K. Schulz R.A. Kim Y. J. Biol. Chem. 2005; 280: 21427-21436Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar, 2Kim Y.H. Choi C.Y. Lee S.J. Conti M.A. Kim Y. J. Biol. Chem. 1998; 273: 25875-25879Abstract Full Text Full Text PDF PubMed Scopus (248) Google Scholar, 3Wang Y. Hofmann T.G. Runkel L. Haaf T. Schaller H. Debatin K. Hug H. Biochim. Biophys. Acta. 2001; 1518: 168-172Crossref PubMed Scopus (21) Google Scholar, 4Moilanen A.M. Karvonen U. Poukka H. Janne O.A. Palvimo J.J. Mol. Biol. Cell. 1998; 9: 2527-2543Crossref PubMed Scopus (100) Google Scholar). HIPK2 interacts with a variety of transcription factors (5Kim E.A. Noh Y.T. Ryu M.J. Kim H.T. Lee S.E. Kim C.H. Lee C. Kim Y.H. Choi C.Y. J. Biol. Chem. 2006; 281: 7489-7497Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar, 6Zhang Q. Nottke A. Goodman R.H. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 2802-2807Crossref PubMed Scopus (70) Google Scholar, 7D'Orazi G. Cecchinelli B. Bruno T. Manni I. Higashimoto Y. Saito S. Gostissa M. Coen S. Marchetti A. Del Sal G. Piaggio G. Fanciulli M. Appella E. Soddu S. Nat. Cell Biol. 2002; 4: 11-19Crossref PubMed Scopus (570) Google Scholar, 8Hofmann T.G. Moller A. Sirma H. Zentgraf H. Taya Y. Droge W. Will H. Schmitz M.L. Nat. Cell Biol. 2002; 4: 1-10Crossref PubMed Scopus (496) Google Scholar), p300/CBP coactivator (9Aikawa Y. Nguyen L.A. Isono K. Takakura N. Tagata Y. Schmitz M.L. Koseki H. Kitabayashi I. EMBO J. 2006; 25: 3955-3965Crossref PubMed Scopus (109) Google Scholar, 10Kim E.J. Park J.S. Um S.J. J. Biol. Chem. 2002; 277: 32020-32028Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar), and Groucho/TLE corepressor (1Choi C.Y. Kim Y.H. Kim Y.O. Park S.J. Kim E.A. Riemenschneider W. Gajewski K. Schulz R.A. Kim Y. J. Biol. Chem. 2005; 280: 21427-21436Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar), thereby regulating target gene expression in a context-dependent manner. The loss of a functional HIPK2 allele induces a reduction of apoptosis and increased numbers of trigeminal ganglia, whereas HIPK2 overexpression in the developing sensory and sympathetic neurons promotes apoptosis in a caspase-dependent manner (11Wiggins A.K. Wei G. Doxakis E. Wong C. Tang A.A. Zang K. Luo E.J. Neve R.L. Reichardt L.F. Huang E.J. J. Cell Biol. 2004; 167: 257-267Crossref PubMed Scopus (85) Google Scholar, 12Doxakis E. Huang E.J. Davies A.M. Curr. Biol. 2004; 14: 1761-1765Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar). The HIPK1 and HIPK2 double-knock-out approach showed that HIPK2 performs overlapping functions with HIPK1 in the mediation of cell proliferation and apoptosis during mouse development (13Isono K. Nemoto K. Li Y. Takada Y. Suzuki R. Katsuki M. Nakagawara A. Koseki H. Mol. Cell Biol. 2006; 26: 2758-2771Crossref PubMed Scopus (91) Google Scholar). A number of key regulatory molecules, including p53, CtBP, Axin, Brn3, Sp100, TP53INP1, and PML, are known to be associated with the function of HIPK2 in the induction of apoptosis (14Rui Y. Xu Z. Lin S. Li Q. Rui H. Luo W. Zhou H.M. Cheung P.Y. Wu Z. Ye Z. Li P. Han J. Lin S.C. EMBO J. 2004; 23: 4583-4594Crossref PubMed Scopus (132) Google Scholar, 15Kanei-Ishii C. Ninomiya-Tsuji J. Tanikawa J. Nomura T. Ishitani T. Kishida S. Kokura K. Kurahashi T. Ichikawa-Iwata E. Kim Y. Matsumoto K. Ishii S. Genes Dev. 2004; 18: 816-829Crossref PubMed Scopus (153) Google Scholar, 16Moller A. Sirma H. Hofmann T.G. Rueffer S. Klimczak E. Droge W. Will H. Schmitz M.L. Cancer Res. 2003; 63: 4310-4314PubMed Google Scholar, 17Moller A. Sirma H. Hofmann T.G. Staege H. Gresko E. Ludi K.S. Klimczak E. Droge W. Will H. Schmitz M.L. Oncogene. 2003; 22: 8731-8737Crossref PubMed Scopus (36) Google Scholar, 18Tomasini R. Samir A.A. Carrier A. Isnardon D. Cecchinelli B. Soddu S. Malissen B. Dagorn J.C. Iovanna J.L. Dusetti N.J. J. Biol. Chem. 2003; 278: 37722-37729Abstract Full Text Full Text PDF PubMed Scopus (131) Google Scholar). UV-induced apoptosis is understood via the action of HIPK2 at the molecular level. HIPK2 is activated and stabilized by UV irradiation and selectively phosphorylates p53 at Ser-46. Thus, the kinase function of HIPK2 increases the expression of p53-target genes and enhances UV-induced apoptosis (7D'Orazi G. Cecchinelli B. Bruno T. Manni I. Higashimoto Y. Saito S. Gostissa M. Coen S. Marchetti A. Del Sal G. Piaggio G. Fanciulli M. Appella E. Soddu S. Nat. Cell Biol. 2002; 4: 11-19Crossref PubMed Scopus (570) Google Scholar, 8Hofmann T.G. Moller A. Sirma H. Zentgraf H. Taya Y. Droge W. Will H. Schmitz M.L. Nat. Cell Biol. 2002; 4: 1-10Crossref PubMed Scopus (496) Google Scholar). Additionally, HIPK2 phosphorylates the Ser-422 of CtBP, and phosphorylated CtBP is degraded via the 26 S proteasome pathway, resulting in apoptosis in p53-deficient cells (19Zhang Q. Yoshimatsu Y. Hildebrand J. Frisch S.M. Goodman R.H. Cell. 2003; 115: 177-186Abstract Full Text Full Text PDF PubMed Scopus (189) Google Scholar). Endogenous HIPK2 protein is barely detected and is induced by UV irradiation or treatment with the chemotherapeutic drug, cisplatin, whereas the levels of HIPK2 mRNA remained unchanged under identical conditions (20Di Stefano V. Blandino G. Sacchi A. Soddu S. D'Orazi G. Oncogene. 2004; 23: 5185-5192Crossref PubMed Scopus (61) Google Scholar). The levels of p53 and Bax increase concomitantly with the induction of HIPK2 (21Di Stefano V. Rinaldo C. Sacchi A. Soddu S. D'Orazi G. Exp. Cell Res. 2004; 293: 311-320Crossref PubMed Scopus (93) Google Scholar). However, it remains to be determined whether HIPK2 is degraded at the protein level, nor is it understood which molecule is responsible for the tight control of HIPK2 levels in cells under normal conditions. homeodomain-interacting protein kinase 2 Skp1-Cullin-F-box ElonginB/C-Cul2/5-SOCS suppressor of cytokine signaling box green fluorescent protein Myc epitope tag glutathione S-transferase ubiquitin ubiquitin-activating enzyme ubiquitin-conjugating enzyme ubiquitin ligase amino acid(s) hemagglutinin short hairpin RNA. homeodomain-interacting protein kinase 2 Skp1-Cullin-F-box ElonginB/C-Cul2/5-SOCS suppressor of cytokine signaling box green fluorescent protein Myc epitope tag glutathione S-transferase ubiquitin ubiquitin-activating enzyme ubiquitin-conjugating enzyme ubiquitin ligase amino acid(s) hemagglutinin short hairpin RNA. The highly controlled degradation of proteins via the ubiquitin-proteasome pathway represents a key mechanism for a variety of cellular activities, including cell cycle regulation and apoptosis. The ubiquitination of proteins requires three enzymes: E1, ubiquitin-activating enzyme; E2, ubiquitin-conjugating enzyme; and E3, ubiquitin ligase (22Ciechanover A. Nat. Mol. Cell Biol. 2005; PubMed Scopus Google Scholar, A. A. 1998; PubMed Scopus Google Scholar). the ubiquitin ligase and the target protein. The of a and a and of E3 associated with E3 enzyme The known are the and the ubiquitin ligase The ubiquitin are a family of E3 in which an protein is responsible for proteins interact with the via and a C-terminal interaction or K. Cell Dev. Biol. 2005; PubMed Scopus Google Scholar, Curr. Biol. 2004; 14: Full Text Full Text PDF PubMed Scopus Google Scholar). The with the The SOCS of cytokine proteins function as that to the M.L. A. J. Biol. Chem. 2005; 280: Full Text Full Text PDF PubMed Scopus Google Scholar, T. K. S. Matsumoto M. D. Genes Dev. 2004; 18: PubMed Scopus Google Scholar). In to the SOCS SOCS box proteins a variety of interaction including the and that to at proteins determined to a C-terminal SOCS These proteins the protein in the of the SOCS box R. S.E. D. Proc. Natl. Acad. Sci. U. S. A. 1998; PubMed Scopus Google Scholar). WSB-1 and as of a of family and an SOCS box in the and of a respectively. the and the of WSB-1 with are well to whether WSB-1 function as an E3 ubiquitin ligase, and to the target of WSB-1 M. A. B. I. M.A. Kim S. A.M. A. C. R. Nat. Cell Biol. 2005; PubMed Scopus Google Scholar, S.J. M. A. M. J. S. J. Oncogene. 26: PubMed Scopus Google Scholar, A. L. M. C. S.M. B. J. Biol. Chem. 2006; 281: Full Text Full Text PDF PubMed Scopus Google Scholar). In we that WSB-1 is an E3 ubiquitin ligase that HIPK2 for degradation via the 26 S proteasome determined that WSB-1 promotes the ubiquitination and degradation of HIPK2, a process in which both and the SOCS box are required for the and degradation of HIPK2. degradation of HIPK2 was blocked in which regulatory mechanisms by which the HIPK2 levels are controlled in cells under normal conditions, and DNA damage the degradation of HIPK2 by Cell and and cells were in with cells were and DNA was the of the and cells were with as and WSB-1 was from The of WSB-1 were from WSB-1 with and the DNA was and of WSB-1 were by of DNA the and of HIPK2 and (5Kim E.A. Noh Y.T. Ryu M.J. Kim H.T. Lee S.E. Kim C.H. Lee C. Kim Y.H. Choi C.Y. J. Biol. Chem. 2006; 281: 7489-7497Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar, C.Y. Kim Y.H. Kim Y. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, Y.H. Choi C.Y. Kim Y. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). The the was by of The and were by with The of WSB-1 for the was the to the of the The were by DNA was conducted the WSB-1 and expression was WSB-1 was by which the WSB-1 the and of in with the Yeast a DNA amino of HIPK2 was the and of and the by with cells with mouse were and the were with The were and The DNA was with a to the HIPK2 and the The interaction and of the proteins were by the of and or and In the in vitro ubiquitination was with in vitro as a and were to the ubiquitin 2 2 of ubiquitin of and of The were for at and were by for in The were by and to The ubiquitinated HIPK2 proteins were detected by In proteins were in E. and were with to the of the The of proteins were by the in vitro proteins were with at for in and three with with the proteins were by and detected by with and of endogenous proteins was the of 2 cells in for and for at of protein were with with and protein at a The were three with The cell and were by and The were with and the were the were with or with by with of cells was as (5Kim E.A. Noh Y.T. Ryu M.J. Kim H.T. Lee S.E. Kim C.H. Lee C. Kim Y.H. Choi C.Y. J. Biol. Chem. 2006; 281: 7489-7497Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar). In cells were and with of and of the WSB-1 expression the cells were with for at and with the of cells with was conducted with a 2 of and The were with of WSB-1 as HIPK2-interacting is known that the levels of HIPK2 protein are increased as the of UV irradiation and cisplatin treatment, both of which are genotoxic that DNA damage (7D'Orazi G. Cecchinelli B. Bruno T. Manni I. Higashimoto Y. Saito S. Gostissa M. Coen S. Marchetti A. Del Sal G. Piaggio G. Fanciulli M. Appella E. Soddu S. Nat. Cell Biol. 2002; 4: 11-19Crossref PubMed Scopus (570) Google Scholar, 8Hofmann T.G. Moller A. Sirma H. Zentgraf H. Taya Y. Droge W. Will H. Schmitz M.L. Nat. Cell Biol. 2002; 4: 1-10Crossref PubMed Scopus (496) Google Scholar, Stefano V. Blandino G. Sacchi A. Soddu S. D'Orazi G. Oncogene. 2004; 23: 5185-5192Crossref PubMed Scopus (61) Google Scholar). However, it remains to be determined whether HIPK2 is stabilized in protein levels by from and which molecule is in In an to the degradation of HIPK2 in cells under normal conditions, the cells were to and the levels of HIPK2 were by The of from was increased via UV irradiation in a manner The administration of DNA damage reagents, as Adriamycin or cisplatin, to cells resulted in induction of the endogenous HIPK2 protein A and the treatment of cells with the proteasome resulted in the accumulation of HIPK2 that HIPK2 be degraded by in cells under normal conditions. A two-hybrid screening was conducted in an to identify cellular proteins that target HIPK2 for HIPK2 for degradation were determined to a for two-hybrid for HIPK2, HIPK2, or C-terminal HIPK2 were the and the protein levels were determined to or treatment with the proteasome The protein levels of HIPK2 and C-terminal HIPK2, HIPK2, were increased as the of treatment 2 and that HIPK2 is degraded by proteasome via its the of was as for the screening of mouse the cellular proteins that were and a showed to WSB-1, a of E3 ubiquitin ligase The WSB-1 a C-terminal that and a SOCS The WSB-1 and HIPK2 were in the two-hybrid and in cells and analysis showed that WSB-1 with HIPK2 The of endogenous HIPK2 with WSB-1 was via with by that WSB-1 is an HIPK2-interacting protein in vitro and in and is associated with HIPK2 in and of HIPK2 by an to whether WSB-1 functions as an E3 ubiquitin ligase against HIPK2, expression were cells with or the WSB-1 expression cells were with to protein the the of the levels of the HIPK2 proteins were by The stability of HIPK2 was by the coexpression of WSB-1 the of HIPK2 was as for two-hybrid screening for the of WSB-1, HIPK2 for degradation by WSB-1 was the of HIPK2, the was degraded by the coexpression of WSB-1 the functional interaction of WSB-1 with HIPK2, of HIPK2 by WSB-1 were under in vitro and in conditions. HIPK2 was polyubiquitinated was in cells with with the ubiquitinated of E1, E2, and WSB-1 were in the These indicate that WSB-1 function as an E3 ubiquitin ligase against HIPK2. of Endogenous WSB-1 HIPK2 we the of WSB-1 knockdown the stability of HIPK2. cells were with of expression for against WSB-1, and WSB-1 levels were by with in endogenous WSB-1 was by the expression of against WSB-1 in a manner. The knockdown of endogenous WSB-1 concomitantly resulted in the of endogenous HIPK2 levels HIPK2 was in a cells were with WSB-1 expression with the expression and the expression levels of endogenous HIPK2 were by The WSB-1 cells be by of the expression at a of to in the cells endogenous HIPK2 at a whereas the cells control or low HIPK2 The of to the cells resulted in a of endogenous HIPK2 of WSB-1 expression showed that WSB-1 HIPK2 in the cells under normal conditions. WSB-1 with HIPK2 is of and an SOCS box in the to in cellular and the SOCS box is known to be in the protein degradation in the ubiquitin ligase C. K. E.J. Sci. Full Text Full Text PDF PubMed Scopus Google Scholar, G. PubMed Scopus Google Scholar, H.M. Sci. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). whether the SOCS box of WSB-1 are required for its interaction with and degradation of HIPK2, a of WSB-1 were and for the analysis of analysis with and WSB-1 showed that of the of WSB-1 the with HIPK2 The of WSB-1 was to as we of WSB-1 to the protein both WSB-1 and C-terminal WSB-1 and SOCS were associated with HIPK2 in cells However, the SOCS box of WSB-1 to HIPK2 in vitro and two-hybrid analysis These indicate that are responsible for the interaction of WSB-1 with HIPK2. WSB-1 of the protein of the to a from the E.J. R. PubMed Scopus Google Scholar), whereas the is from the in amino including a of are conserved from the to of whether the of WSB-1, the SOCS is in its interaction with HIPK2, we conserved and with the WSB-1 which a and the SOCS The of WSB-1 with WSB-1 the SOCS box was These that WSB-1 interacts with HIPK2 via its and the SOCS of WSB-1 for of we determined the WSB-1 required for HIPK2 A of WSB-1 was cells with the expression and HIPK2 degradation was by WSB-1 and and were to HIPK2. However, to the and degradation of HIPK2 by WSB-1 and WSB-1 of the SOCS box to HIPK2, its interaction with HIPK2 remained The of WSB-1 to HIPK2 was determined with the ubiquitination of the HIPK2 in with the the WSB-1 or the C-terminal SOCS box HIPK2, whereas WSB-1 ubiquitinated HIPK2 In the the SOCS box HIPK2 in vitro These indicate that and the SOCS box are required for the of HIPK2 by WSB-1 and the of the E3 ligase for the degradation of HIPK2, respectively. DNA of HIPK2 by WSB-1 in we to whether the of HIPK2 is blocked by administration of DNA damage as Adriamycin and cisplatin, as HIPK2 was to be stabilized under conditions. and expression were and the cells were to Adriamycin or cisplatin. in the coexpression of WSB-1 resulted in the degradation of HIPK2 However, HIPK2 was degraded by WSB-1 in the cells with cisplatin, or was determined that the of HIPK2 was increased DNA that both the of HIPK2 and the of the were increased T.G. Moller A. Sirma H. Zentgraf H. Taya Y. Droge W. Will H. Schmitz M.L. Nat. Cell Biol. 2002; 4: 1-10Crossref PubMed Scopus (496) Google Scholar, Stefano V. Rinaldo C. Sacchi A. Soddu S. D'Orazi G. Exp. Cell Res. 2004; 293: 311-320Crossref PubMed Scopus (93) Google Scholar). In an to the of HIPK2 degradation under DNA damage conditions, a was to whether the of WSB-1 to HIPK2 is the of HIPK2. The of HIPK2 and showed that HIPK2 and to HIPK2 and with the the of HIPK2 by treatment a of HIPK2 in the and the of HIPK2 to of the HIPK2 The of WSB-1 with HIPK2 in the administration of Adriamycin was in the The of WSB-1 to both HIPK2 and HIPK2 were Adriamycin The HIPK2 and WSB-1 was with HIPK2 These that WSB-1 was of HIPK2 cells were to genotoxic which conditions in which HIPK2 be activated and stabilized its from E3 ubiquitin ligase HIPK2 is a key for UV-induced apoptosis. the activated and stabilized HIPK2 the of the cell cycle and induces apoptosis via of target as p53 and CtBP Q. Nottke A. Goodman R.H. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 2802-2807Crossref PubMed Scopus (70) Google Scholar, 7D'Orazi G. Cecchinelli B. Bruno T. Manni I. Higashimoto Y. Saito S. Gostissa M. Coen S. Marchetti A. Del Sal G. Piaggio G. Fanciulli M. Appella E. Soddu S. Nat. Cell Biol. 2002; 4: 11-19Crossref PubMed Scopus (570) Google Scholar, 8Hofmann T.G. Moller A. Sirma H. Zentgraf H. Taya Y. Droge W. Will H. Schmitz M.L. Nat. Cell Biol. 2002; 4: 1-10Crossref PubMed Scopus (496) Google Scholar). the and of HIPK2 be both to and the of cells to the that DNA In we that HIPK2 is ubiquitinated and degraded by WSB-1, box protein in cells under normal conditions, the of cells to UV or cisplatin the of HIPK2 by HIPK2 remains and for the induction of apoptosis. WSB-1 is a protein that and a C-terminal SOCS box R. S.E. D. Proc. Natl. Acad. Sci. U. S. A. 1998; PubMed Scopus Google Scholar). in were in the of proteins and in a variety of of which are in C. K. E.J. Sci. Full Text Full Text PDF PubMed Scopus Google Scholar, E.J. R. PubMed Scopus Google Scholar). The of to function as responsible for of a protein to the ubiquitin E3 ligase Curr. Biol. 2004; 14: Full Text Full Text PDF PubMed Scopus Google Scholar, L.A. D. Wu M. R. H. H. Cell 2006; PubMed Scopus Google Scholar). 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In the of both and the of the degradation of target proteins is at the during the cell The be to the degradation of HIPK2 by normal conditions, the HIPK2 is degraded by the cells are to genotoxic including UV or cisplatin, HIPK2 is which it to from by These that the regulation of the HIPK2 levels is the the and ubiquitination of HIPK2. be that the expression of WSB-1 is induced by the signaling pathway during development D. S. Dev. PubMed Scopus Google Scholar). WSB-1 is in and developing as well as in in which signaling to a in the of the the and of HIPK2 target including and are by signaling J. J. Cell Dev. Biol. PubMed Scopus Google Scholar, L. M. Dev. Biol. 2005; PubMed Scopus Google Scholar). of the family function as a or in a context-dependent manner C.Y. Kim Y.H. Kim Y. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, C.Y. Lee Kim Y.H. Park T. Schulz R.A. Kim Y. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). Groucho/TLE corepressor is a for the family and its corepressor are by (1Choi C.Y. Kim Y.H. Kim Y.O. Park S.J. Kim E.A. Riemenschneider W. Gajewski K. Schulz R.A. Kim Y. J. Biol. Chem. 2005; 280: 21427-21436Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar). of transcription factors and as are to be mechanism of of it be to the regulation of HIPK2 by WSB-1 induction signaling during are to Kim for and of Y. of for expression