Eukaryotic Cell
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF 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 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 Zhang, H.
Right arrow Articles by Soll, D. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Zhang, H.
Right arrow Articles by Soll, D. R.
Eukaryotic Cell, February 2003, p. 62-75, Vol. 2, No. 1
1535-9778/03/$08.00+0     DOI: 10.1128/EC.2.1.62-75.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Constitutively Active Protein Kinase A Disrupts Motility and Chemotaxis in Dictyostelium discoideum

Hui Zhang,1 Paul J. Heid,1 Deborah Wessels,1 Karla J. Daniels,1 Tien Pham,1 William F. Loomis,2 and David R. Soll1*

W. M. Keck Dynamic Image Analysis Facility, Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242,1 Department of Biology, University of California, San Diego, La Jolla, California 920392

Received 27 August 2002/ Accepted 28 October 2002

The deletion of the gene for the regulatory subunit of protein kinase A (PKA) results in constitutively active PKA in the pkaR mutant. To investigate the role of PKA in the basic motile behavior and chemotaxis of Dictyostelium discoideum, pkaR mutant cells were subjected to computer-assisted two- and three-dimensional motion analysis. pkaR mutant cells crawled at only half the speed of wild-type cells in buffer, chemotaxed in spatial gradients of cyclic AMP (cAMP) but with reduced efficiency, were incapable of suppressing lateral pseudopods in the front of temporal waves of cAMP, a requirement for natural chemotaxis, did not exhibit the normal velocity surge in response to the front of a wave, and were incapable of chemotaxing toward an aggregation center in natural waves generated by wild-type cells that made up the majority of cells in mixed cultures. Many of the behavioral defects appeared to be the result of the constitutively ovoid shape of the pkaR mutant cells, which forced the dominant pseudopod off the substratum and to the top of the cell body. The behavioral abnormalities that pkaR mutant cells shared with regA mutant cells are discussed by considering the pathway ERK2 | RegA | [cAMP] -> PKA, which emanates from the front of a wave. The results demonstrate that cells must suppress PKA activity in order to elongate along a substratum, suppress lateral-pseudopod formation, and crawl and chemotax efficiently. The results also implicate PKA activation in dismantling cell polarity at the peak and in the back of a natural cAMP wave.

* Corresponding author. Mailing address: Department of Biological Science, BBE 302, University of Iowa, Iowa City, IA 52242. Phone: (319) 335-1117. Fax: (319) 335-2772. E-mail: david-soll{at}uiowa.edu.

Eukaryotic Cell, February 2003, p. 62-75, Vol. 2, No. 1
1535-9778/03/$08.00+0     DOI: 10.1128/EC.2.1.62-75.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Appl. Environ. Microbiol. Infect. Immun. J. Bacteriol.
Mol. Cell Biol. Microbiol. Mol. Biol. Rev. ALL ASM JOURNALS
Copyright © 2003 by the American Society for Microbiology.