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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

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.

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

Journal Article Type Article
Acceptance Date May 1, 2008
Online Publication Date May 26, 2008
Publication Date Jun 2, 2008
Deposit Date Nov 13, 2014
Publicly Available Date Nov 13, 2014
Journal Journal of cell biology
Print ISSN 0021-9525
Publisher Rockefeller University Press
Peer Reviewed Peer Reviewed
Volume 181
Issue 5
Pages 747-760
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
Public URL https://hull-repository.worktribe.com/output/465016
Publisher URL http://jcb.rupress.org/content/181/5/747
Additional Information Copy of article first published in Journal of cell biology, 2008, v.181, issue 5
Contract Date Nov 13, 2014

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http://www.rupress.org/terms_v1

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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