Characterization of a DNA exit gate in the human cohesin ring

• Published in: Science (American Association for the Advancement of Science) Vol. 346; no. 6212; pp. 968 - 972
• Main Authors: in 't Veld, Pim J. Huis, Herzog, Franz, Ladurner, Rene, Davidson, Iain F., Piric, Sabina, Kreidl, Emanuel, Bhaskara, Venugopal, Aebersold, Ruedi, Peters, Jan-Michael
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 21.11.2014; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Animals; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell adhesion & migration; Cell Cycle Proteins - chemistry; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Chondroitin Sulfate Proteoglycans - chemistry; Chondroitin Sulfate Proteoglycans - genetics; Chondroitin Sulfate Proteoglycans - metabolism; Chromatids; Chromatin; Chromatin - metabolism; Chromosomal Proteins, Non-Histone - chemistry; Chromosomal Proteins, Non-Histone - genetics; Chromosomal Proteins, Non-Histone - metabolism; Chromosome Segregation; Chromosomes; Cleavage; Cohesins; Cohesion; Deoxyribonucleic acid; Dimers; DNA; DNA - metabolism; DNA Replication; DNA-Binding Proteins; Gates; HeLa cells; Histological shadowing; Humans; Laser modes; Lasers; Mass Spectrometry; Mathematical rings; Microscopy, Electron; Molecular Sequence Data; Mutation; Mutations; Nuclear Proteins - chemistry; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Phosphoproteins - chemistry; Phosphoproteins - genetics; Phosphoproteins - metabolism; Protein Multimerization; Protein Structure, Tertiary; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Rings (mathematics); Separase - metabolism; Strands
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1256904

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.