The hsSsu72 phosphatase is a cohesin-binding protein that regulates the resolution of sister chromatid arm cohesion

EMBO J. 2010 Oct 20;29(20):3544-57. doi: 10.1038/emboj.2010.217. Epub 2010 Sep 3.


Cohesin is a multiprotein complex that establishes sister chromatid cohesion from S phase until mitosis or meiosis. In vertebrates, sister chromatid cohesion is dissolved in a stepwise manner: most cohesins are removed from the chromosome arms via a process that requires polo-like kinase 1 (Plk1), aurora B and Wapl, whereas a minor amount of cohesin, found preferentially at the centromere, is cleaved by separase following its activation by the anaphase-promoting complex/cyclosome. Here, we report that our budding yeast two-hybrid assay identified hsSsu72 phosphatase as a Rad21-binding protein. Additional experiments revealed that Ssu72 directly interacts with Rad21 and SA2 in vitro and in vivo, and associates with sister chromatids in human cells. Interestingly, depletion or mutational inactivation of Ssu72 phosphatase activity caused the premature resolution of sister chromatid arm cohesion, whereas the overexpression of Ssu72 yielded high resistance to this resolution. Interestingly, it appears that Ssu72 regulates the cohesion of chromosome arms but not centromeres, and acts by counteracting the phosphorylation of SA2. Thus, our study provides important new evidence, suggesting that Ssu72 is a novel cohesin-binding protein capable of regulating cohesion between sister chromatid arms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Chromatids / metabolism*
  • Chromatin / metabolism
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Chromosome Segregation*
  • DNA-Binding Proteins
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • Protein Binding
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Two-Hybrid System Techniques


  • Carrier Proteins
  • Cell Cycle Proteins
  • Chromatin
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Phosphoproteins
  • RAD21 protein, human
  • Recombinant Fusion Proteins
  • cohesins
  • SSU72 protein, human