title: RhoA and RhoC have distinct roles in migration and invasion by acting through different targets.
abstract: Several studies suggest that RhoA and RhoC, despite their sequence similarity, have different roles in cell migration and invasion, but the molecular basis for this is not known. Using RNAi, we show that RhoA-depleted cells became elongated and extended multiple Rac1-driven narrow protrusions in 2D and 3D environments, leading to increased invasion. These phenotypes were caused by combined but distinct effects of the Rho-regulated kinases ROCK1 and ROCK2. Depletion of ROCK2 induced multiple delocalized protrusions and reduced migratory polarity, whereas ROCK1 depletion selectively led to cell elongation and defective tail retraction. In contrast, RhoC depletion increased cell spreading and induced Rac1 activation around the periphery in broad lamellipodia, thereby inhibiting directed migration and invasion. These effects of RhoC depletion are mediated by the formin FMNL3, which we identify as a new target of RhoC but not RhoA. We propose that RhoA contributes to migratory cell polarity through ROCK2-mediated suppression of Rac1 activity in lamellipodia, whereas RhoC promotes polarized migration through FMNL3 by restricting lamellipodial broadening.
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, England, UK.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Vega
authors.forename: Gilbert
authors.initials: G
authors.lastname: Fruhwirth
authors.forename: Tony
authors.initials: T
authors.lastname: Ng
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Ridley
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement; D016764:Cell Polarity; D048430:Cell Shape; D005260:Female; D000080865:Formins; D005838:Genotype; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness; D010641:Phenotype; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D011506:Proteins / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D000075024:rhoC GTP-Binding Protein
chemical_list: C476209:FMNL3 protein, human; D000080865:Formins; D011506:Proteins; C107953:RAC1 protein, human; C066737:RHOA protein, human; C515851:ROCK1 protein, human; C515852:ROCK2 protein, human; D054460:rho-Associated Kinases; C066690:RHOC protein, human; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D000075024:rhoC GTP-Binding Protein