Angiomotin regulates endothelial cell-cell junctions and cell motility.
We have previously identified angiomotin by its ability to bind to and mediate the anti-angiogenic properties of angiostatin. In vivo and in vitro data indicate an essential role of angiomotin in endothelial cell motility. Here we show that angiostatin binds angiomotin on the cell surface and provide evidence for a transmembrane model for the topology of both p80 and p130 angiomotin isoforms. Immunofluorescence analysis shows that angiomotin co-localized with ZO-1 in cell-cell contacts in endothelial cells in vitro and in angiogenic blood vessels of the postnatal mouse retina in vivo. Transfection of p80 as well as p130 angiomotin in Chinese hamster ovary cells resulted in junctional localization of both isoforms. Furthermore, p130 angiomotin could recruit ZO-1 to actin stress fibers. The p130 but not p80 isoform could be coprecipitated with MAGI-1b, a component of endothelial tight junctions. Paracellular permeability, as measured by diffusion of fluorescein isothiocyanate-dextran, was reduced by p80 and p130 angiomotin expression with 70 and 88%, respectively, compared with control. Angiostatin did not have any effect on cell permeability but inhibited the migration of angiomotin-expressing cells in the Boyden chamber assay. We conclude that angiomotin, in addition to controlling cell motility, may play a role in the assembly of endothelial cell-cell junctions.
Bratt
Anders
A
Department of Oncology and Pathology, Cancer Centrum Karolinska, Karolinska Institutet, R8:03 Karolinska University Hospital, 171 76 Stockholm, Sweden.
Birot
Olivier
O
Sinha
Indranil
I
Veitonmäki
Niina
N
Aase
Karin
K
Ernkvist
Mira
M
Holmgren
Lars
L
D017398:Alternative Splicing; D000091082:Angiomotins; D000091304:Angiopoietin-Like Protein 1; D043168:Angiostatins / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D019921:Biotinylation; D015153:Blotting, Western; D016466:CHO Cells; D002196:Capillaries / Q000166:cytology; D002352:Carrier Proteins / Q000502:physiology*; D002417:Cattle; D002450:Cell Communication; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D019295:Computational Biology; D006224:Cricetinae; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004058:Diffusion; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology; D016650:Fluorescein-5-isothiocyanate / Q000494:pharmacology; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins; D008856:Microscopy, Fluorescence; D017830:Octoxynol; D010539:Permeability; D010750:Phosphoproteins / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D012160:Retina / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130 / Q000378:metabolism; D013997:Time Factors; D014357:Trypsin / Q000494:pharmacology; D062826:Zonula Occludens-1 Protein; D009687:Nuclear Proteins
D000091082:Angiomotins; D000091304:Angiopoietin-Like Protein 1; D043168:Angiostatins; D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D016650:Fluorescein-5-isothiocyanate; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D017830:Octoxynol; D010750:Phosphoproteins; D011092:Polyethylene Glycols; D020033:Protein Isoforms; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D014357:Trypsin; D062826:Zonula Occludens-1 Protein; C423985:AMOT protein, human; C510063:AMOTL1 protein, human; C449807:Amotl1 protein, mouse; C493838:Rbl2 protein, mouse; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; C010615:Nonidet P-40; C526165:WDR48 protein, human; D009687:Nuclear Proteins