TY - JOUR
T1 - Fibrinogen binds to integrin α5β1 via the Carboxyl-terminal RGD site of the Aα-chain
AU - Suehiro, Kazuhisa
AU - Mizuguchi, Jun
AU - Nishiyama, Kiyoto
AU - Iwanaga, Sadaaki
AU - Farrell, David H.
AU - Ohtaki, Sachiya
PY - 2000
Y1 - 2000
N2 - Fibrinogen interactions with vascular endothelial cells are implicated in various physiological and pathophysiological events, including angiogenesis and wound healing. We have shown previously that integrin α5β1 is a fibrinogen receptor on endothelial cells [Suehiro, K., Gailit, J., and Plow, E.F. (1997) J. Biol. Chem. 272, 5360-5366]. In the present study, we have characterized fibrinogen interactions with purified α5β1 and have identifled the recognition sequence in fibrinogen for α5β1. The binding of fibrinogen to immobilized α5β1 was selectively supported by Mn2+. Fibrinogen bound to purified α5β1 in a time-dependent, specific, and saturable manner in the presence of Mn2+, and the binding was blocked completely by Arg-Gly-Asp (RGD)-containing peptides and by anti-α5 and anti-α5β1 monoclonal antibodies. A monoclonal antibody directed to the C-termlnal RGD sequence at Aα572-574 significantly inhibited the binding of fibrinogen to α5β1, whereas monoclonal antibodies directed to either the N-terminal RGD sequence at Aα95-97 or the C-terminus of the γ-chain did not. Furthermore, substituting RGE for RGD at position Aα95-97 in recombinant fibrinogen had a minimal effect on binding, whereas substituting RGE for RGD at position Aα572-574 decreased binding by 90%. These results demonstrate that the C-terminal RGD sequence at Aα572-574 is required for the interaction of fibrinogen with α5β1.
AB - Fibrinogen interactions with vascular endothelial cells are implicated in various physiological and pathophysiological events, including angiogenesis and wound healing. We have shown previously that integrin α5β1 is a fibrinogen receptor on endothelial cells [Suehiro, K., Gailit, J., and Plow, E.F. (1997) J. Biol. Chem. 272, 5360-5366]. In the present study, we have characterized fibrinogen interactions with purified α5β1 and have identifled the recognition sequence in fibrinogen for α5β1. The binding of fibrinogen to immobilized α5β1 was selectively supported by Mn2+. Fibrinogen bound to purified α5β1 in a time-dependent, specific, and saturable manner in the presence of Mn2+, and the binding was blocked completely by Arg-Gly-Asp (RGD)-containing peptides and by anti-α5 and anti-α5β1 monoclonal antibodies. A monoclonal antibody directed to the C-termlnal RGD sequence at Aα572-574 significantly inhibited the binding of fibrinogen to α5β1, whereas monoclonal antibodies directed to either the N-terminal RGD sequence at Aα95-97 or the C-terminus of the γ-chain did not. Furthermore, substituting RGE for RGD at position Aα95-97 in recombinant fibrinogen had a minimal effect on binding, whereas substituting RGE for RGD at position Aα572-574 decreased binding by 90%. These results demonstrate that the C-terminal RGD sequence at Aα572-574 is required for the interaction of fibrinogen with α5β1.
KW - Divalent cations
KW - Fibrinogen
KW - Fibronectin receptor
KW - Integrin
KW - RGD
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U2 - 10.1093/oxfordjournals.jbchem.a022804
DO - 10.1093/oxfordjournals.jbchem.a022804
M3 - Article
C2 - 11011154
AN - SCOPUS:0033772764
SN - 0021-924X
VL - 128
SP - 705
EP - 710
JO - Journal of Biochemistry
JF - Journal of Biochemistry
IS - 4
ER -