title: Dissociation of cohesin from chromosome arms and loss of arm cohesion during early mitosis depends on phosphorylation of SA2.
abstract: Cohesin is a protein complex that is required to hold sister chromatids together. Cleavage of the Scc1 subunit of cohesin by the protease separase releases the complex from chromosomes and thereby enables the separation of sister chromatids in anaphase. In vertebrate cells, the bulk of cohesin dissociates from chromosome arms already during prophase and prometaphase without cleavage of Scc1. Polo-like kinase 1 (Plk1) and Aurora-B are required for this dissociation process, and Plk1 can phosphorylate the cohesin subunits Scc1 and SA2 in vitro, consistent with the possibility that cohesin phosphorylation by Plk1 triggers the dissociation of cohesin from chromosome arms. However, this hypothesis has not been tested yet, and in budding yeast it has been found that phosphorylation of Scc1 by the Polo-like kinase Cdc5 enhances the cleavability of cohesin, but does not lead to separase-independent dissociation of cohesin from chromosomes. To address the functional significance of cohesin phosphorylation in human cells, we have searched for phosphorylation sites on all four subunits of cohesin by mass spectrometry. We have identified numerous mitosis-specific sites on Scc1 and SA2, mutated them, and expressed nonphosphorylatable forms of both proteins stably at physiological levels in human cells. The analysis of these cells lines, in conjunction with biochemical experiments in vitro, indicate that Scc1 phosphorylation is dispensable for cohesin dissociation from chromosomes in early mitosis but enhances the cleavability of Scc1 by separase. In contrast, our data reveal that phosphorylation of SA2 is essential for cohesin dissociation during prophase and prometaphase, but is not required for cohesin cleavage by separase. The similarity of the phenotype obtained after expression of nonphosphorylatable SA2 in human cells to that seen after the depletion of Plk1 suggests that SA2 is the critical target of Plk1 in the cohesin dissociation pathway.
authors.affiliation: Research Institute of Molecular Pathology, Vienna, Austria.
authors.forename: Silke
authors.initials: S
authors.lastname: Hauf
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Roitinger
authors.forename: Birgit
authors.initials: B
authors.lastname: Koch
authors.forename: Christina M
authors.initials: CM
authors.lastname: Dittrich
authors.forename: Karl
authors.initials: K
authors.lastname: Mechtler
authors.forename: Jan-Michael
authors.initials: JM
authors.lastname: Peters
mesh_terms: D019943:Amino Acid Substitution; D000705:Anaphase / Q000502:physiology; D034961:Antigens, Nuclear / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D002877:Chromosomes, Human / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010750:Phosphoproteins; D010766:Phosphorylation; D029701:Saccharomyces cerevisiae Proteins; D012854:Sister Chromatid Exchange; D000097722:Cohesins
chemical_list: D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D029701:Saccharomyces cerevisiae Proteins; D000097722:Cohesins; C490529:MCD1 protein, S cerevisiae; C508565:STAG2 protein, human
references.citation: Curr Biol. 2004 Apr 6;14(7):560-72
references.pmid: 15062096
references.citation: Cell. 2003 Mar 21;112(6):765-77
references.pmid: 12654244
references.citation: Cell. 2000 Oct 27;103(3):375-86
references.pmid: 11081625
references.citation: Nature. 2003 Jun 26;423(6943):1002-9
references.pmid: 12827206
references.citation: Chromosoma. 2001 Dec;110(7):478-86
references.pmid: 11862455
references.citation: Mol Cell. 2003 Mar;11(3):571-5
references.pmid: 12667442
references.citation: Cell. 2001 May 18;105(4):459-72
references.pmid: 11371343
references.citation: FASEB J. 2000 Mar;14(3):581-92
references.pmid: 10698974
references.citation: Bioessays. 2003 Dec;25(12):1178-91
references.pmid: 14635253
references.citation: Curr Biol. 2004 Jul 13;14(13):1187-93
references.pmid: 15242616
references.citation: Science. 2004 Feb 27;303(5662):1367-70
references.pmid: 14752166
references.citation: BMC Mol Biol. 2002 Apr 17;3:3
references.pmid: 11960554
references.citation: Mol Cell. 2002 Mar;9(3):515-25
references.pmid: 11931760
references.citation: Nature. 1996 May 30;381(6581):438-41
references.pmid: 8632802
references.citation: Science. 2001 Aug 17;293(5533):1320-3
references.pmid: 11509732
references.citation: Science. 2003 Feb 21;299(5610):1228-31
references.pmid: 12595692
references.citation: Genes Dev. 1996 Dec 15;10(24):3081-93
references.pmid: 8985178
references.citation: Curr Biol. 2004 Feb 17;14(4):287-301
references.pmid: 14972679
references.citation: Science. 1999 Jul 16;285(5426):418-22
references.pmid: 10411507
references.citation: Cell. 2000 Oct 27;103(3):399-410
references.pmid: 11081627
references.citation: Genes Dev. 2000 Nov 1;14(21):2757-70
references.pmid: 11069892
references.citation: Genes Dev. 2002 Dec 1;16(23):3004-16
references.pmid: 12464631
references.citation: Cell. 2001 May 18;105(4):445-57
references.pmid: 11371342
references.citation: Genes Dev. 2002 Mar 1;16(5):560-70
references.pmid: 11877376
references.citation: J Biol Chem. 1995 Mar 31;270(13):7703-11
references.pmid: 7706319
references.citation: Cell. 1997 Oct 3;91(1):35-45
references.pmid: 9335333
references.citation: PLoS Biol. 2005 Mar;3(3):e86
references.pmid: 15737064
references.citation: Anal Bioanal Chem. 2003 Aug;376(7):946-51
references.pmid: 12856097
references.citation: Cell. 2003 Oct 3;115(1):109-21
references.pmid: 14532007
references.citation: Cell. 1998 Jun 12;93(6):1067-76
references.pmid: 9635435
references.citation: Mol Cell. 2002 Apr;9(4):773-88
references.pmid: 11983169
references.citation: Nature. 2004 Feb 5;427(6974):510-7
references.pmid: 14730319
references.citation: Genes Dev. 1998 Jul 1;12(13):1986-97
references.pmid: 9649503
references.citation: Mol Cell. 2000 Feb;5(2):243-54
references.pmid: 10882066
references.citation: EMBO J. 2003 Dec 15;22(24):6598-609
references.pmid: 14657031
references.citation: Curr Biol. 2003 Dec 2;13(23):2058-64
references.pmid: 14653995
references.citation: Cell. 1995 Oct 20;83(2):247-56
references.pmid: 7585942
references.citation: Nature. 1999 Jul 1;400(6739):37-42
references.pmid: 10403247
references.citation: Cell. 2003 Feb 21;112(4):423-40
references.pmid: 12600308
references.citation: J Biol Chem. 2003 Jul 11;278(28):25277-80
references.pmid: 12738781
references.citation: J Biol Chem. 2001 Feb 16;276(7):5059-67
references.pmid: 11073952
references.citation: J Cell Biol. 2000 Nov 13;151(4):749-62
references.pmid: 11076961
references.citation: Mol Cell. 2002 May;9(5):931-43
references.pmid: 12049731
references.citation: Exp Cell Res. 2004 May 15;296(1):80-5
references.pmid: 15120997
references.citation: J Cell Biol. 2003 Apr 28;161(2):281-94
references.pmid: 12707311
references.citation: Cell. 2001 Dec 14;107(6):715-26
references.pmid: 11747808
references.citation: J Cell Biol. 2000 Aug 7;150(3):405-16
references.pmid: 10931856
references.citation: Cell. 1997 Oct 3;91(1):47-57
references.pmid: 9335334
references.citation: J Cell Biol. 1998 Mar 9;140(5):1003-12
references.pmid: 9490715
references.citation: Genes Dev. 2002 Mar 1;16(5):571-82
references.pmid: 11877377
references.citation: EMBO J. 2004 Aug 4;23(15):3144-53
references.pmid: 15241476
references.citation: Nat Rev Mol Cell Biol. 2004 Jun;5(6):429-40
references.pmid: 15173822