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Linking Ras to myosin function: RasGEF Q, a Dictyostelium exchange factor for RasB, affects myosin II functions

Mondal, Subhanjan; Bakthavatsalam, Deenadayalan; Steimle, Paul; Gassen, Berthold; Rivero, Francisco; Noegel, Angelika A.

Authors

Subhanjan Mondal

Deenadayalan Bakthavatsalam

Paul Steimle

Berthold Gassen

Francisco Rivero

Angelika A. Noegel

Abstract

Ras guanine nucleotide exchange factor (GEF) Q, a nucleotide exchange factor from Dictyostelium discoideum, is a 143-kD protein containing RasGEF domains and a DEP domain. We show that RasGEF Q can bind to F-actin, has the potential to form complexes with myosin heavy chain kinase (MHCK) A that contain active RasB, and is the predominant exchange factor for RasB. Overexpression of the RasGEF Q GEF domain activates RasB, causes enhanced recruitment of MHCK A to the cortex, and leads to cytokinesis defects in suspension, phenocopying cells expressing constitutively active RasB, and myosin-null mutants. RasGEF Q(-) mutants have defects in cell sorting and slug migration during later stages of development, in addition to cell polarity defects. Furthermore, RasGEF Q(-) mutants have increased levels of unphosphorylated myosin II, resulting in myosin II overassembly. Collectively, our results suggest that starvation signals through RasGEF Q to activate RasB, which then regulates processes requiring myosin II.

Journal Article Type Article
Publication Date Jun 2, 2008
Journal Journal of cell biology
Print ISSN 0021-9525
Electronic ISSN 1540-8140
Publisher Rockefeller University Press
Peer Reviewed Peer Reviewed
Volume 181
Issue 5
Pages 747-760
Institution Citation Mondal, S., Bakthavatsalam, D., Steimle, P., Gassen, B., Rivero, F., & Noegel, A. A. (2008). Linking Ras to myosin function: RasGEF Q, a Dictyostelium exchange factor for RasB, affects myosin II functions. Journal of Cell Biology, 181(5), 747-760. https://doi.org/10.1083/jcb.200710111
DOI https://doi.org/10.1083/jcb.200710111
Keywords Actins; Animals; Chemotaxis; Cyclic AMP; Cytokinesis; Dictyostelium; Genetic techniques; Guanine nucleotide exchange factors; Light; Models; Biological; Myosin type II; Myosins; Phosphorylation; Protein binding; Protein structure; Tertiary; Proteins; Reco
Publisher URL http://jcb.rupress.org/content/181/5/747
Copyright Statement © 2008 Mondal et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons....icenses/by-nc-sa/3.0/).
Additional Information Copy of article first published in Journal of cell biology, 2008, v.181, issue 5

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Copyright Statement
© 2008 Mondal et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).




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