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Xenopus Cds1 is regulated by DNA-dependent protein kinase and ATR during the cell cycle checkpoint response to

Troy D McSherry1, Paul R Mueller

  • 1Center for Molecular Oncology, Department of Biochemistry and Molecular Biology, University of Chicago, JFK R318, 924 E. 57th St., Chicago, IL 60637, USA.

Molecular and Cellular Biology
|October 29, 2004
PubMed

Insights

Xenopus Cds1 (XCds1) regulation involves multiple kinases, including ATR and DNA-PK, which are crucial for cell cycle control. Phosphorylation triggers XCds1 activation and dissociation from the ATR complex, ensuring proper DNA damage response.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Checkpoint kinase Cds1 (Chk2) is vital for cell cycle arrest, DNA repair, and apoptosis.
  • Proper Cds1 regulation is essential for cellular responses to DNA damage.
  • ATM kinase regulates human Cds1 (hCds1), but other kinases are involved in Xenopus Cds1 (XCds1) regulation.

Purpose of the Study:

  • To investigate the roles of ATR and DNA-PK in regulating Xenopus Cds1 (XCds1).
  • To elucidate the mechanism of XCds1 activation in response to DNA damage.

Main Methods:

  • Studied the association of XCds1 with ATR complex under normal cell cycle conditions.
  • Analyzed the phosphorylation of XCds1 in response to double-stranded DNA breaks.
  • Investigated the roles of DNA-PK, ATM, and ATR in XCds1 phosphorylation and activation.

Main Results:

  • Nonactivated XCds1 constitutively associates with a Xenopus ATR complex via an SH3 binding region.
  • DNA-PK phosphorylates serine 39 on XCds1, followed by phosphorylation of other sites by ATM, ATR, and/or DNA-PK.
  • These phosphorylations induce XCds1 dissociation from the ATR complex and promote its full activation.

Conclusions:

  • XCds1 activation requires sequential phosphorylation by multiple phosphoinositide 3-kinase-related kinases.
  • Protein-protein dissociation and autophosphorylation are critical for checkpoint-mediated XCds1 activation.

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