Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. STKE, 1 March 2005
Vol. 2005, Issue 273, p. tw78
[DOI: 10.1126/stke.2732005tw78]

EDITORS' CHOICE

MICROBIOLOGY GTPase Implicated in Bacterial DNA Damage Checkpoint

In eukaryotic cells, defects in replication initiate a checkpoint signaling pathway that halts cell division so that cells are protected from deadly effects of DNA damage. Although it makes sense that prokaryotes would also benefit from such a protective response, an equivalent signaling mechanism has not been defined. A possible component of such a pathway is described by Foti et al., who used a genetic screen in Escherichia coli to identify mutations that increased sensitivity of the bacterial cells to the replication inhibitor hydroxyurea. They identified a mutation in the gene encoding ObgE, a GTPase (guanosine triphosphatase) related to Ras. ObgE is a member of a family of GTPases that are present in eubacteria and eukaryotes that have been ascribed a broad range of possible functions in various organisms, including sporulation, vegetative growth, and stress responses. In E. coli, obgE is an essential gene, but it appears also to have a function that may serve as part of a DNA damage checkpoint. Genetic interactions of obgE mutants with other mutants in genes whose products function in DNA repair supported such a role. A mutation designed to inhibit GTPase activity of ObgE did inhibit its function, but whether GTP- and GDP-bound forms of the protein serve distinct roles and whether its activity is regulated by other factors (as the eukaryotic GTPases are) remain to be explored.

J. J. Foti, J. Schienda, V. A. Sutera, S. T. Lovett, A bacterial G protein-mediated response to replication arrest. Mol. Cell 17, 549-560 (2005). [PubMed]

Citation: GTPase Implicated in Bacterial DNA Damage Checkpoint. Sci. STKE 2005, tw78 (2005).


To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882