Laura M. Breshears a, Deborah Wessels b, David R. Soll b, and Margaret A. Titus a,1
-Author Affiliations
aDepartment of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455; and
bDepartment of Biological Sciences, University of Iowa, Iowa City, IA 52242
Edited* by James A. Spudich, Stanford University, Stanford, CA, and approved March 11, 2010 (received for review August 28, 2009)
Abstract
MyTH/FERM (myosin tail homology 4/band 4.1, ezrin, radixin, and moesin) myosins have roles in cellular adhesion, extension of actin-filled projections such as filopodia and stereocilia, and directional migration. The amoebaDictyostelium discoideum expresses a simple complement of MyTH/FERM myosins, a class VII (M7) myosin required for cell-substrate adhesion and a unique myosin named MyoG. Mutants lacking MyoG exhibit a wide range of normal actin-based behaviors, including chemotaxis to folic acid, but have a striking defect in polarization and chemotaxis to cAMP. Although the myoGmutants respond to cAMP stimulation by increasing persistence and weakly increasing levels of cortical F-actin, they do not polarize; instead, they maintain a round shape and move slowly and randomly when exposed to a chemotactic gradient. The mutants also fail to activate and localize PI3K to the membrane closest to the source of chemoattractant. These data reveal a role for a MyTH/FERM myosin in mediating early chemotactic signaling and suggest that MyTH/FERM proteins have conserved roles in signaling and the generation of cell polarity.
actin cytoskeleton cell signaling cell motility cytoskeletal dynamics
Footnotes
1To whom correspondence should be addressed. E-mail: titus004@umn.edu.
Author contributions: L.M.B., D.W., D.R.S., and M.A.T. designed research; L.M.B., D.W., and M.A.T. performed research; M.A.T. contributed new reagents/analytic tools; L.M.B., D.W., D.R.S., and M.A.T. analyzed data; and L.M.B., D.W., D.R.S., and M.A.T. wrote the paper.
↵*This Direct Submission article had a prearranged editor.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0909796107/DCSupplemental.
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