Download MendeleyStructural basis of Rad53 kinase activation by dimerization and activation segment exchange.
Wybenga-Groot, L.E., Ho, C.S., Sweeney, F.D., Ceccarelli, D.F., McGlade, C.J., Durocher, D., Sicheri, F.(2014) Cell Signal 26: 1825-1836
- PubMed: 24815189
- DOI: https://doi.org/10.1016/j.cellsig.2014.05.004
- Primary Citation of Related Structures:
4PDP, 4PDS - PubMed Abstract:
The protein kinase Rad53 is a key regulator of the DNA damage checkpoint in budding yeast. Its human ortholog, CHEK2, is mutated in familial breast cancer and mediates apoptosis in response to genotoxic stress. Autophosphorylation of Rad53 at residue Thr354 located in the kinase activation segment is essential for Rad53 activation. In this study, we assessed the requirement of kinase domain dimerization and the exchange of its activation segment during the Rad53 activation process. We solved the crystal structure of Rad53 in its dimeric form and found that disruption of the observed head-to-tail, face-to-face dimer structure decreased Rad53 autophosphorylation on Thr354 in vitro and impaired Rad53 function in vivo. Moreover, we provide critical functional evidence that Rad53 trans-autophosphorylation may involve the interkinase domain exchange of helix αEF via an invariant salt bridge. These findings suggest a mechanism of autophosphorylation that may be broadly applicable to other protein kinases.
Organizational Affiliation:
The Arthur and Sonia Labatt Brain Tumour Research Centre and Program in Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Electronic address: leanne.wybenga.groot@utoronto.ca.
