KA1-targeted regulatory domain mutations activate Chk1 in the absence of DNA damage

Gong, E. Y., Smits, V. A.J., Fumagallo, F., Piscitello, D., Morrice, N., Freire, R. and Gillespie, D. A. (2015) KA1-targeted regulatory domain mutations activate Chk1 in the absence of DNA damage. Scientific Reports, 5, 10856. (doi: 10.1038/srep10856) (PMID:26039276) (PMCID:PMC4454167)

Abstract

The Chk1 protein kinase is activated in response to DNA damage through ATR-mediated phosphorylation at multiple serine-glutamine (SQ) residues within the C-terminal regulatory domain, however the molecular mechanism is not understood. Modelling indicates a high probability that this region of Chk1 contains a kinase-associated 1 (KA1) domain, a small, compact protein fold found in multiple protein kinases including SOS2, AMPK and MARK3. We introduced mutations into Chk1 designed to disrupt specific structural elements of the predicted KA1 domain. Remarkably, six of seven Chk1 KA1 mutants exhibit constitutive biological activity (Chk1-CA) in the absence of DNA damage, profoundly arresting cells in G2 phase of the cell cycle. Cell cycle arrest induced by selected Chk1-CA mutants depends on kinase catalytic activity, which is increased several-fold compared to wild-type, however phosphorylation of the key ATR regulatory site serine 345 (S345) is not required. Thus, mutations targeting the putative Chk1 KA1 domain confer constitutive biological activity by circumventing the need for ATR-mediated positive regulatory phosphorylation.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gong, Dr Eun Yeung and Gillespie, Professor David and Piscitello, Miss Desiree and Morrice, Dr Nicholas
• Authors: Gong, E. Y., Smits, V. A.J., Fumagallo, F., Piscitello, D., Morrice, N., Freire, R., and Gillespie, D. A.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Scientific Reports
• Publisher: Nature Publishing Group
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2015 The Authors
• First Published: First published in Scientific Reports 5:10856
• Publisher Policy: Reproduced under a Creative Commons License