title: Structure and function of cohesin's Scc3/SA regulatory subunit.
abstract: Sister chromatid cohesion involves entrapment of sister DNAs by a cohesin ring created through association of a kleisin subunit (Scc1) with ATPase heads of Smc1/Smc3 heterodimers. Cohesin's association with chromatin involves subunits recruited by Scc1: Wapl, Pds5, and Scc3/SA, in addition to Scc2/4 loading complex. Unlike Pds5, Wapl, and Scc2/4, Scc3s are encoded by all eukaryotic genomes. Here, a crystal structure of Scc3 reveals a hook-shaped protein composed of tandem α helices. Its N-terminal domain contains a conserved and essential surface (CES) present even in organisms lacking Pds5, Wapl, and Scc2/4, while its C-terminal domain binds a section of the kleisin Scc1. Scc3 turns over in G2/M while maintaining cohesin's association with chromosomes and it promotes de-acetylation of Smc3 upon Scc1 cleavage.
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors.forename: Maurici B
authors.initials: MB
authors.lastname: Roig
authors.affiliation: MRC Laboratory of Molecular Biology, Structural Studies Division, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom. Electronic address: jyl@mrc-lmb.cam.ac.uk.
authors.forename: Jan
authors.initials: J
authors.lastname: Löwe
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors.forename: Kok-Lung
authors.initials: KL
authors.lastname: Chan
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Beckouët
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors.forename: Jean
authors.initials: J
authors.lastname: Metson
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom. Electronic address: kim.nasmyth@bioch.ox.ac.uk.
authors.forename: Kim
authors.initials: K
authors.lastname: Nasmyth
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism*; D059565:G2 Phase Cell Cycle Checkpoints; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; C119635:IRR1 protein, S cerevisiae; C490529:MCD1 protein, S cerevisiae; D021122:Protein Subunits; C120372:SMC3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
keywords: Cohesin complex; Eco1 acetylation; Maintenance of cohesion; Releasing activity; SA/STAG domain; Scc3; Sister chromatid separation; Smc proteins