title: Coordinated RhoA signaling at the leading edge and uropod is required for T cell transendothelial migration.
abstract: Transendothelial migration (TEM) is a tightly regulated process whereby leukocytes migrate from the vasculature into tissues. Rho guanosine triphosphatases (GTPases) are implicated in TEM, but the contributions of individual Rho family members are not known. In this study, we use an RNA interference screen to identify which Rho GTPases affect T cell TEM and demonstrate that RhoA is critical for this process. RhoA depletion leads to loss of migratory polarity; cells lack both leading edge and uropod structures and, instead, have stable narrow protrusions with delocalized protrusions and contractions. By imaging a RhoA activity biosensor in transmigrating T cells, we find that RhoA is locally and dynamically activated at the leading edge, where its activation precedes both extension and retraction events, and in the uropod, where it is associated with ROCK-mediated contraction. The Rho guanine nucleotide exchange factor (GEF) GEF-H1 contributes to uropod contraction but does not affect the leading edge. Our data indicate that RhoA activity is dynamically regulated at the front and back of T cells to coordinate TEM.
authors: Randall Division of Cell and Molecular Biophysics, King's College London, London, England, UK.
authors: Sarah J
authors: SJ
authors: Heasman
authors: Leo M
authors: LM
authors: Carlin
authors: Susan
authors: S
authors: Cox
authors: Tony
authors: T
authors: Ng
authors: Anne J
authors: AJ
authors: Ridley
mesh_terms: D000818:Animals; D002460:Cell Line; D021961:Cell Membrane Structures / Q000378:metabolism* / Q000648:ultrastructure; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity; D004727:Endothelium / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D064067:Rho Guanine Nucleotide Exchange Factors; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology / Q000502:physiology; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C577356:ARHGEF2 protein, human; D020662:Guanine Nucleotide Exchange Factors; D034741:RNA, Small Interfering; D064067:Rho Guanine Nucleotide Exchange Factors; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein