MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Xu, X.
Right arrow Articles by Stern, D. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Xu, X.
Right arrow Articles by Stern, D. F.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, June 2002, p. 4419-4432, Vol. 22, No. 12
0270-7306/02/$04.00+0     DOI: 10.1128/MCB.22.12.4419-4432.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Chk2 Activation and Phosphorylation-Dependent Oligomerization

Xingzhi Xu, Lyuben M. Tsvetkov, and David F. Stern*

Department of Pathology, School of Medicine, Yale University, New Haven, Connecticut 06510

Received 17 September 2001/ Returned for modification 29 October 2001/ Accepted 21 March 2002

The tumor suppressor gene CHK2 encodes a versatile effector serine/threonine kinase involved in responses to DNA damage. Chk2 has an amino-terminal SQ/TQ cluster domain (SCD), followed by a forkhead-associated (FHA) domain and a carboxyl-terminal kinase catalytic domain. Mutations in the SCD or FHA domain impair Chk2 checkpoint function. We show here that autophosphorylation of Chk2 produced in a cell-free system requires trans phosphorylation by a wortmannin-sensitive kinase, probably ATM or ATR. Both SQ/TQ sites and non-SQ/TQ sites within the Chk2 SCD can be phosphorylated by active Chk2. Amino acid substitutions in the SCD and the FHA domain impair auto- and trans-kinase activities of Chk2. Chk2 forms oligomers that minimally require the FHA domain of one Chk2 molecule and the SCD within another Chk2 molecule. Chk2 oligomerization in vivo increases after DNA damage, and when damage is induced by gamma irradiation, this increase requires ATM. Chk2 oligomerization is phosphorylation dependent and can occur in the absence of other eukaryotic proteins. Chk2 can cross-phosphorylate another Chk2 molecule in an oligomeric complex. Induced oligomerization of a Chk2 chimera in vivo concomitant with limited DNA damage augments Chk2 kinase activity. These results suggest that Chk2 oligomerization regulates Chk2 activation, signal amplification, and transduction in DNA damage checkpoint pathways.

* Corresponding author. Mailing address: Department of Pathology, School of Medicine, Yale University, 310 Cedar Street, BML 342, New Haven, CT 06510. Phone: (203) 785-4832. Fax: (203)785-7467. E-mail: Df.stern{at}yale.edu.

Molecular and Cellular Biology, June 2002, p. 4419-4432, Vol. 22, No. 12
0022-538X/02/$04.00+0     DOI: 10.1128/MCB.22.12.4419-4432.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2002 by the American Society for Microbiology. All rights reserved.