title: The Amot/Patj/Syx signaling complex spatially controls RhoA GTPase activity in migrating endothelial cells.
abstract: Controlled regulation of Rho GTPase activity is an essential component mediating growth factor-stimulated migration. We have previously shown that angiomotin (Amot), a membrane-associated scaffold protein, plays a critical role during vascular patterning and endothelial migration during embryogenesis. However, the signaling pathways by which Amot controls directional migration are not known. Here we have used peptide pull-down and yeast 2-hybrid (Y2H) screening to identify proteins that interact with the C-terminal PDZ-binding motifs of Amot and its related proteins AmotL1 and 2. We report that Amot and its related proteins bind to the RhoA GTPase exchange factor (RhoGEF) protein Syx. We show that Amot forms a ternary complex together with Patj (or its paralogue Mupp1) and Syx. Using FRET analysis, we provide evidence that Amot controls targeting of RhoA activity to lamellipodia in vitro. We also report that, similar to Amot, morpholino knockdown of Syx in zebrafish results in inhibition of migration of intersegmental arteries. Taken together, our results indicate that the directional migration of capillaries in the embryo is governed by the Amot:Patj/Mupp1:Syx signaling that controls local GTPase activity.
authors.affiliation: Department of Oncology and Pathology, Cancer Centrum Karolinska, Karolinska Institutet, Karolinska Hospital, Stockholm, Sweden.
authors.forename: Mira
authors.initials: M
authors.lastname: Ernkvist
authors.forename: Nathalie
authors.initials: N
authors.lastname: Luna Persson
authors.forename: Stéphane
authors.initials: S
authors.lastname: Audebert
authors.forename: Patrick
authors.initials: P
authors.lastname: Lecine
authors.forename: Indranil
authors.initials: I
authors.lastname: Sinha
authors.forename: Miaoliang
authors.initials: M
authors.lastname: Liu
authors.forename: Marc
authors.initials: M
authors.lastname: Schlueter
authors.forename: Arie
authors.initials: A
authors.lastname: Horowitz
authors.forename: Karin
authors.initials: K
authors.lastname: Aase
authors.forename: Thomas
authors.initials: T
authors.lastname: Weide
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Borg
authors.forename: Arindam
authors.initials: A
authors.lastname: Majumdar
authors.forename: Lars
authors.initials: L
authors.lastname: Holmgren
mesh_terms: D000091082:Angiomotins; D000818:Animals; D030801:Animals, Genetically Modified; D001011:Aorta / Q000166:cytology; D002196:Capillaries / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000166:cytology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008840:Microfilament Proteins; D018919:Neovascularization, Physiologic / Q000502:physiology; D054731:PDZ Domains / Q000502:physiology; D064067:Rho Guanine Nucleotide Exchange Factors; D062725:Tight Junction Proteins; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: C423985:AMOT protein, human; C510063:AMOTL1 protein, human; C508566:AMOTL2 protein, human; D000091082:Angiomotins; D002352:Carrier Proteins; D020662:Guanine Nucleotide Exchange Factors; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; C107903:PATJ protein, human; D064067:Rho Guanine Nucleotide Exchange Factors; D062725:Tight Junction Proteins; D029961:Zebrafish Proteins; C532476:plekhg5a protein, zebrafish; D020742:rhoA GTP-Binding Protein