ANGPTL3 stimulates endothelial cell adhesion and migration via integrin alpha vbeta 3 and induces blood vessel formation in vivo.
The angiopoietin family of secreted factors is functionally defined by the C-terminal fibrinogen (FBN)-like domain, which mediates binding to the Tie2 receptor and thereby facilitates a cascade of events ultimately regulating blood vessel formation. By screening expressed sequence tag data bases for homologies to a consensus FBN-like motive, we have identified ANGPTL3, a liver-specific, secreted factor consisting of an N-terminal coiled-coil domain and the C-terminal FBN-like domain. Co-immunoprecipitation experiments, however, failed to detect binding of ANGPTL3 to the Tie2 receptor. A molecular model of the FBN-like domain of ANGPTL3 was generated and predicted potential binding to integrins. This hypothesis was experimentally confirmed by the finding that recombinant ANGPTL3 bound to alpha(v)beta(3) and induced integrin alpha(v)beta(3)-dependent haptotactic endothelial cell adhesion and migration and stimulated signal transduction pathways characteristic for integrin activation, including phosphorylation of Akt, mitogen-activated protein kinase, and focal adhesion kinase. When tested in the rat corneal assay, ANGPTL3 strongly induced angiogenesis with comparable magnitude as observed for vascular endothelial growth factor-A. Moreover, the C-terminal FBN-like domain alone was sufficient to induce endothelial cell adhesion and in vivo angiogenesis. Taken together, our data demonstrate that ANGPTL3 is the first member of the angiopoietin-like family of secreted factors binding to integrin alpha(v)beta(3) and suggest a possible role in the regulation of angiogenesis.
Camenisch
Gieri
G
Department of Molecular Oncology, Genentech, Inc., South San Francisco, California 94080, USA.
Pisabarro
Maria Teresa
MT
Sherman
Daniel
D
Kowalski
Joe
J
Nagel
Mark
M
Hass
Phil
P
Xie
Ming-Hong
MH
Gurney
Austin
A
Bodary
Sarah
S
Liang
Xiao Huan
XH
Clark
Kevin
K
Beresini
Maureen
M
Ferrara
Napoleone
N
Gerber
Hans-Peter
HP
D000595:Amino Acid Sequence; D042702:Angiopoietin-2; D000091303:Angiopoietin-Like Protein 3; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003315:Cornea / Q000378:metabolism; D004727:Endothelium / Q000166:cytology*; D005340:Fibrinogen / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System; D051379:Mice; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D051381:Rats; D019030:Receptors, Vitronectin / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D042702:Angiopoietin-2; D000091303:Angiopoietin-Like Protein 3; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; C404495:Angptl3 protein, mouse; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D019030:Receptors, Vitronectin; D011994:Recombinant Proteins; D005340:Fibrinogen; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; C496052:Ptk2 protein, rat