Antonio A. Iniesta1, Nathan J. Hillson1,2, and Lucy Shapiro3
-Author Affiliations
Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305
↵2Current address: Fuels Synthesis Division, Joint BioEnergy Institute, Emeryville, CA 94608.
Contributed by Lucy Shapiro, February 12, 2010 (sent for review February 4, 2010)
↵1A.I. and N.H. contributed equally to this work.
Abstract
Caulobacter crescentus integrates phospho-signaling pathways and transcription factor regulatory cascades to drive the cell cycle. Despite the essential role of the CckA histidine kinase in the control of cell cycle events, the factors that signal its activation at a specific time in the cell cycle have remained elusive. A conditional genetic screen for CckA mislocalization mutants, using automated fluorescence microscopy and an image processing platform, revealed that the essential DivL protein kinase promotes CckA localization, autophosphorylation, and activity at the new cell pole. The transient accumulation of DivL at the new cell pole, but not its kinase activity, is required for the localization and activation of CckA. Because DivL and CckA accumulate at the same cell pole after the initiation of DNA replication and were found to interact in vivo, we propose that DivL recruits CckA to the pole, thereby promoting its autophosphorylation and activity.
Caulobacter CckA DivL polar localization
Footnotes
3To whom correspondence may be addressed: shapiro@stanford.edu.
Author contributions: A.I., N.H., and L.S. designed research; A.I. and N.H. performed research; A.I. and N.H. analyzed data; and A.I., N.H., and L.S. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/1001767107/DCSupplemental.
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