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Structure and activation mechanism of the CHK2 DNA damage checkpoint kinase

Zhenjian Cai1, Nabil H Chehab, Nikola P Pavletich

  • 1Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.

Molecular Cell
|September 29, 2009
PubMed

Insights

CHK2 protein kinase activation relies on dimerization, involving FHA-kinase and FHA-FHA interactions. Mutations like Ile157 disrupt this dimerization, impacting cancer predisposition and DNA damage signaling.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Structural Biology

Background:

  • The CHK2 protein kinase is crucial for DNA damage checkpoint signaling.
  • CHK2 mutations are implicated in hereditary and sporadic cancers.
  • Activation of CHK2 involves phosphorylation by ATM kinase and subsequent dimerization.

Purpose of the Study:

  • To elucidate the structural mechanism of CHK2 dimerization and activation.
  • To understand the role of specific interactions in CHK2 dimerization.
  • To explain the functional consequences of cancer-associated CHK2 mutations.

Main Methods:

  • X-ray crystallography of dimeric CHK2
  • Biochemical assays
  • Mutational analysis

Main Results:

  • The crystal structure reveals productive CHK2 dimerization involves intermolecular FHA-kinase and FHA-FHA interactions.
  • The Ile157 mutation disrupts the FHA-kinase interface, preventing dimerization and autophosphorylation.
  • Dimerization positions kinase active sites for transphosphorylation, facilitating activation.

Conclusions:

  • CHK2 activation is a structurally regulated process dependent on specific intermolecular interactions.
  • The identified structural interfaces explain the mechanism of CHK2 activation and the impact of cancer mutations.
  • Understanding CHK2 dimerization provides insights into DNA damage response pathways and cancer development.

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