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Curr Biol. 2011 Jan 11;21(1):12-24. doi: 10.1016/j.cub.2010.12.004. Epub 2010 Dec 23.

ATP hydrolysis is required for relocating cohesin from sites occupied by its Scc2/4 loading complex.

Author information

1
Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
2
Laboratory of In Silico Functional Genomics, Graduate School of Bioscience, Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8501, Japan.
3
Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
#
Contributed equally

Abstract

BACKGROUND:

The Cohesin complex that holds sister chromatins together until anaphase is comprised of three core subunits: Smc1 and Smc3, two long-rod-shaped proteins with an ABC-like ATPase head (nucleotide-binding domain [NBD]) and a dimerization domain linked by a 50 nm long intramolecular antiparallel coiled-coil, and Scc1, an α-kleisin subunit interconnecting the NBD domains of Smc1 and Smc3. Cohesin's stable association with chromosomes is thought to involve entrapment of chromatin fibers by its tripartite Smc1-Smc3-Scc1 ring via a poorly understood mechanism dependent on a separate Scc2/4 loading complex. A key issue concerns where entrapment initially takes place: at sites where cohesin is found stably associated or at distinct "loading" sites from which it translocates.

RESULTS:

In this study, we find transition state mutant versions (Smc1E1158Q and SmcE1155Q) defective in disengagement of their nucleotide binding domains (NBDs), unlike functional cohesin, colocalize with Scc2/4 at core centromeres, sites that catalyze wild-type cohesin's recruitment to sequences 20 kb or more away. In addition to Scc2/4, the unstable association of transition state complexes with core centromeres requires Scc1's association with Smc1 and Smc3 NBDs, ATP-driven NBD engagement, cohesin's Scc3 subunit, and its hinge domain.

CONCLUSION:

We propose that cohesin's association with chromosomes is driven by two key events. NBD engagement driven by ATP binding produces an unstable association with specific loading sites like core centromeres, whereas subsequent ATP hydrolysis triggers DNA entrapment, which permits translocation along chromatin fibers.

PMID:
21185190
PMCID:
PMC4763544
DOI:
10.1016/j.cub.2010.12.004
[Indexed for MEDLINE]
Free PMC Article

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