Angiomotin: an angiostatin binding protein that regulates endothelial cell migration and tube formation.
Angiostatin, a circulating inhibitor of angiogenesis, was identified by its ability to maintain dormancy of established metastases in vivo. In vitro, angiostatin inhibits endothelial cell migration, proliferation, and tube formation, and induces apoptosis in a cell type-specific manner. We have used a construct encoding the kringle domains 1--4 of angiostatin to screen a placenta yeast two-hybrid cDNA library for angiostatin-binding peptides. Here we report the identification of angiomotin, a novel protein that mediates angiostatin inhibition of migration and tube formation of endothelial cells. In vivo, angiomotin is expressed in the endothelial cells of capillaries as well as larger vessels of the human placenta. Upon expression of angiomotin in HeLa cells, angiomotin bound and internalized fluorescein-labeled angiostatin. Transfected angiomotin as well as endogenous angiomotin protein were localized to the leading edge of migrating endothelial cells. Expression of angiomotin in endothelial cells resulted in increased cell migration, suggesting a stimulatory role of angiomotin in cell motility. However, treatment with angiostatin inhibited migration and tube formation in angiomotin-expressing cells but not in control cells. These findings indicate that angiostatin inhibits cell migration by interfering with angiomotin activity in endothelial cells.
Center for Genomics Research and Microbiology and Tumor Biology Center, Karolinska Institutet, S-171 76 Stockholm, Sweden.
B
B
Troyanovsky
T
T
Levchenko
G
G
Månsson
O
O
Matvijenko
L
L
Holmgren
D000595:Amino Acid Sequence; D000091082:Angiomotins; D043168:Angiostatins; D000818:Animals; D001808:Blood Vessels / Q000254:growth & development / Q000502:physiology; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D017930:Genes, Reporter; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D018082:Kringles / Q000235:genetics; D008565:Membrane Proteins; D051379:Mice; D008840:Microfilament Proteins; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010446:Peptide Fragments / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D020798:Two-Hybrid System Techniques
C423985:AMOT protein, human; D000091082:Angiomotins; D002352:Carrier Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D043168:Angiostatins; D010958:Plasminogen; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse