title: The CRL4Cdt2 ubiquitin ligase targets the degradation of p21Cip1 to control replication licensing.
abstract: The faithful replication of genomic DNA is crucial for maintaining genome stability. In eukaryotes, DNA rereplication is prevented by the temporal regulation of replication licensing. Replication-licensing factors are required to form prereplicative complexes during G1 phase, but are inactivated in S phase to prevent rereplication. A vertebrate CUL4 CRL ubiquitin ligase (CRL4) complex containing Cdt2 as the substrate recognition subunit promotes proper DNA replication, in part, by degrading the replication-licensing factor Cdt1 during S phase. We show that the Caenorhabditis elegans CRL4(Cdt2) complex has a conserved role in degrading Cdt1. Furthermore, we show that CRL4(Cdt2) restrains replication licensing in both C. elegans and humans by targeting the degradation of the cyclin-dependent kinase (CDK) inhibitors CKI-1 and p21(Cip1), respectively. Human CRL4(Cdt2) targets the degradation of p21 in S phase, with the in vivo ubiquitylation of p21 by CRL4(Cdt2) dependent on p21 binding to PCNA. Inactivation of Cdt2 induces rereplication, which requires the presence of the CDK inhibitor p21. Strikingly, coinactivation of CRL4(Cdt2) and SCF(Skp2) (which redundantly targets p21 degradation) prevents the nuclear export of the replication-licensing factor Cdc6 during S phase, and the block on nuclear export is dependent on p21. Our work defines the degradation of p21 as a critical aspect of replication licensing in human cells.
authors.affiliation: Department of Cellular Biology, University of Georgia, Athens, Georgia 30602 USA.
authors.forename: Youngjo
authors.initials: Y
authors.lastname: Kim
authors.forename: Natalia G
authors.initials: NG
authors.lastname: Starostina
authors.forename: Edward T
authors.initials: ET
authors.lastname: Kipreos
mesh_terms: D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000378:metabolism; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D004261:DNA Replication; D006801:Humans; D006868:Hydrolysis; D034741:RNA, Small Interfering; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D034741:RNA, Small Interfering; D044767:Ubiquitin-Protein Ligases
references.citation: J Biol Chem. 2006 Feb 17;281(7):3753-6
references.pmid: 16407242
references.citation: J Biol Chem. 1998 Feb 27;273(9):4838-42
references.pmid: 9478924
references.citation: Nucleic Acids Res. 2008 Jan;36(1):67-75
references.pmid: 17984070
references.citation: J Biol Chem. 2006 Mar 10;281(10):6246-52
references.pmid: 16407252
references.citation: Mol Cell. 2003 Apr;11(4):997-1008
references.pmid: 12718885
references.citation: Nucleic Acids Res. 1992 Jan 25;20(2):376
references.pmid: 1311073
references.citation: Mol Cell Biol. 2004 Aug;24(16):7140-50
references.pmid: 15282313
references.citation: EMBO Rep. 2006 Nov;7(11):1134-9
references.pmid: 17039252
references.citation: Cell Div. 2008 Feb 18;3:7
references.pmid: 18282298
references.citation: Mol Cell. 2006 Sep 1;23(5):709-21
references.pmid: 16949367
references.citation: Genes Dev. 2006 Nov 15;20(22):3117-29
references.pmid: 17085480
references.citation: J Biol Chem. 2003 Jul 11;278(28):25752-7
references.pmid: 12730199
references.citation: Mol Cell Biol. 2008 Feb;28(4):1218-29
references.pmid: 18086887
references.citation: Dev Cell. 2007 Jul;13(1):127-39
references.pmid: 17609115
references.citation: Mol Cell. 2000 Feb;5(2):403-10
references.pmid: 10882081
references.citation: Nature. 2004 Mar 11;428(6979):190-3
references.pmid: 15014502
references.citation: Mol Cell. 2007 Jun 22;26(6):775-80
references.pmid: 17588513
references.citation: Nat Cell Biol. 2006 Jan;8(1):84-90
references.pmid: 16362051
references.citation: EMBO J. 2005 Jan 26;24(2):395-404
references.pmid: 15616577
references.citation: Mol Cell Biol. 2007 Feb;27(4):1394-406
references.pmid: 17145765
references.citation: Genome Res. 1999 Oct;9(10):909-23
references.pmid: 10523520
references.citation: Genome Biol. 2001;2(1):RESEARCH0002
references.pmid: 11178279
references.citation: Nature. 2001 Jun 28;411(6841):1068-73
references.pmid: 11429609
references.citation: Nat Cell Biol. 1999 Aug;1(4):207-14
references.pmid: 10559918
references.citation: Cell Cycle. 2006 Aug;5(15):1675-80
references.pmid: 16861906
references.citation: Mol Cell Biol. 2007 Sep;27(18):6457-68
references.pmid: 17636032
references.citation: Nature. 1994 Jun 16;369(6481):574-8
references.pmid: 7911228
references.citation: Proc Natl Acad Sci U S A. 2003 Sep 2;100(18):10231-6
references.pmid: 12925736
references.citation: Genes Dev. 2007 Jan 15;21(2):184-94
references.pmid: 17234884
references.citation: Nature. 2006 Oct 5;443(7111):590-3
references.pmid: 16964240
references.citation: Methods Mol Biol. 2005;301:37-46
references.pmid: 15917624
references.citation: Genetics. 1996 Dec;144(4):1425-36
references.pmid: 8978031
references.citation: Nat Cell Biol. 1999 Aug;1(4):193-9
references.pmid: 10559916
references.citation: Nat Cell Biol. 2006 Nov;8(11):1277-83
references.pmid: 17041588
references.citation: J Cell Biol. 2004 May 24;165(4):473-82
references.pmid: 15159417
references.citation: Proc Natl Acad Sci U S A. 1998 Sep 15;95(19):11324-9
references.pmid: 9736735
references.citation: Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):12817-21
references.pmid: 8917502
references.citation: Curr Biol. 2007 Jun 5;17(11):966-72
references.pmid: 17509881
references.citation: Genes Dev. 2006 Nov 1;20(21):2949-54
references.pmid: 17079684
references.citation: Cell. 1985 Apr;40(4):767-74
references.pmid: 3886158
references.citation: EMBO J. 2006 Mar 8;25(5):1126-36
references.pmid: 16482215
references.citation: Dev Cell. 2008 Feb;14(2):159-69
references.pmid: 18267085
references.citation: Genes Dev. 2005 Jan 1;19(1):114-26
references.pmid: 15598982
references.citation: Nucleic Acids Res. 2008 Mar;36(5):1713-22
references.pmid: 18263614
references.citation: Mol Cell. 2007 Aug 3;27(3):462-73
references.pmid: 17679094
references.citation: Mol Cell Biol. 1998 Jan;18(1):546-57
references.pmid: 9418901
references.citation: Genes Cells. 2005 Jan;10(1):63-73
references.pmid: 15670214
references.citation: Cell Div. 2007 Feb 06;2:5
references.pmid: 17280619
references.citation: Cell Cycle. 2008 Jan 15;7(2):146-50
references.pmid: 18256526
references.citation: Cell Div. 2007 Jun 12;2:18
references.pmid: 17565698
references.citation: Genes Dev. 2007 Mar 1;21(5):497-518
references.pmid: 17344412
references.citation: Ciba Found Symp. 1992;170:187-96; discussion 196-204
references.pmid: 1483345
references.citation: Nature. 2003 Jun 19;423(6942):885-9
references.pmid: 12815436
references.citation: Curr Biol. 1999 Jun 17;9(12):661-4
references.pmid: 10375532
references.citation: Cell. 2007 May 18;129(4):665-79
references.pmid: 17512402
references.citation: EMBO J. 2003 Dec 1;22(23):6365-77
references.pmid: 14633995