title: Characterization of a DNA exit gate in the human cohesin ring.
abstract: Chromosome segregation depends on sister chromatid cohesion mediated by cohesin. The cohesin subunits Smc1, Smc3, and Scc1 form tripartite rings that are thought to open at distinct sites to allow entry and exit of DNA. However, direct evidence for the existence of open forms of cohesin is lacking. We found that cohesin's proposed DNA exit gate is formed by interactions between Scc1 and the coiled-coil region of Smc3. Mutation of this interface abolished cohesin's ability to stably associate with chromatin and to mediate cohesion. Electron microscopy revealed that weakening of the Smc3-Scc1 interface resulted in opening of cohesin rings, as did proteolytic cleavage of Scc1. These open forms may resemble intermediate states of cohesin normally generated by the release factor Wapl and the protease separase, respectively.
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
authors.forename: Pim J
authors.initials: PJ
authors.lastname: Huis in 't Veld
authors.affiliation: Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zurich, Switzerland. Department of Biochemistry, Gene Center, Ludwig-Maximilian University, 81377 Munich, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Herzog
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
authors.forename: Rene
authors.initials: R
authors.lastname: Ladurner
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
authors.forename: Iain F
authors.initials: IF
authors.lastname: Davidson
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
authors.forename: Sabina
authors.initials: S
authors.lastname: Piric
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Kreidl
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
authors.forename: Venugopal
authors.initials: V
authors.lastname: Bhaskara
authors.affiliation: Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zurich, Switzerland.
authors.forename: Ruedi
authors.initials: R
authors.lastname: Aebersold
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria. peters@imp.ac.at.
authors.forename: Jan-Michael
authors.initials: JM
authors.lastname: Peters
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011508:Chondroitin Sulfate Proteoglycans / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation; D004247:DNA / Q000378:metabolism*; D004261:DNA Replication; D004268:DNA-Binding Proteins; D006801:Humans; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D064247:Separase / Q000378:metabolism; D000097722:Cohesins
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D011508:Chondroitin Sulfate Proteoglycans; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D064247:Separase; D000097722:Cohesins; C429022:RAD21 protein, human; C492318:SMC3 protein, human; C488092:WAPL protein, human