title: A handcuff model for the cohesin complex.
abstract: The cohesin complex is responsible for the accurate separation of sister chromatids into two daughter cells. Several models for the cohesin complex have been proposed, but the one-ring embrace model currently predominates the field. However, the static configuration of the embrace model is not flexible enough for cohesins to perform their functions during DNA replication, transcription, and DNA repair. We used coimmunoprecipitation, a protein fragment complement assay, and a yeast two-hybrid assay to analyze the protein-protein interactions among cohesin subunits. The results show that three of the four human cohesin core subunits (Smc1, Smc3, and Rad21) interact with themselves in an Scc3 (SA1/SA2)-dependent manner. These data support a two-ring handcuff model for the cohesin complex, which is flexible enough to establish and maintain sister chromatid cohesion as well as ensure the fidelity of chromosome segregation in higher eukaryotes.
authors.affiliation: Department of Pediatric Hematology/Oncology, Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Nenggang
authors.initials: N
authors.lastname: Zhang
authors.forename: Sergey G
authors.initials: SG
authors.lastname: Kuznetsov
authors.forename: Shyam K
authors.initials: SK
authors.lastname: Sharan
authors.forename: Kaiyi
authors.initials: K
authors.lastname: Li
authors.forename: Pulivarthi H
authors.initials: PH
authors.lastname: Rao
authors.forename: Debananda
authors.initials: D
authors.lastname: Pati
mesh_terms: D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002842:Chromatids / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005816:Genetic Complementation Test; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D008164:Luminescent Proteins / Q000378:metabolism; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D000097722:Cohesins
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D008164:Luminescent Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D010750:Phosphoproteins; D021122:Protein Subunits; D000097722:Cohesins; C429022:RAD21 protein, human