Spatiotemporal dynamics of RhoA activity in migrating cells.
Rho family GTPases regulate the actin and adhesion dynamics that control cell migration. Current models postulate that Rac promotes membrane protrusion at the leading edge and that RhoA regulates contractility in the cell body. However, there is evidence that RhoA also regulates membrane protrusion. Here we use a fluorescent biosensor, based on a novel design preserving reversible membrane interactions, to visualize the spatiotemporal dynamics of RhoA activity during cell migration. In randomly migrating cells, RhoA activity is concentrated in a sharp band directly at the edge of protrusions. It is observed sporadically in retracting tails, and is low in the cell body. RhoA activity is also associated with peripheral ruffles and pinocytic vesicles, but not with dorsal ruffles induced by platelet-derived growth factor (PDGF). In contrast to randomly migrating cells, PDGF-induced membrane protrusions have low RhoA activity, potentially because PDGF strongly activates Rac, which has previously been shown to antagonize RhoA activity. Our data therefore show that different extracellular cues induce distinct patterns of RhoA signalling during membrane protrusion.
University of North Carolina at Chapel Hill, Department of Pharmacology and Lineberger Cancer Center, Chapel Hill, North Carolina 27599, USA. khahn@med.unc.edu
Olivier
O
Pertz
Louis
L
Hodgson
Richard L
RL
Klemke
Klaus M
KM
Hahn
D016475:3T3 Cells; D000818:Animals; D015374:Biosensing Techniques; D002465:Cell Movement; D022081:Cell Surface Extensions / Q000187:drug effects / Q000378:metabolism*; D005347:Fibroblasts; D051379:Mice; D010873:Pinocytosis; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D013997:Time Factors; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D010982:Platelet-Derived Growth Factor; D020744:rac GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein