| First Author | Kauf AC | Year | 2001 |
| Journal | Biochemistry | Volume | 40 |
| Issue | 31 | Pages | 9159-66 |
| PubMed ID | 11478883 | Mgi Jnum | J:70699 |
| Mgi Id | MGI:2138016 | Doi | 10.1021/bi010503x |
| Citation | Kauf AC, et al. (2001) Recognition of Fibronectin by the Platelet Integrin alphaIIbbeta3 Involves an Extended Interface with Multiple Electrostatic Interactions. Biochemistry 40(31):9159-66 |
| abstractText | Normal platelet function is dependent on the ability of integrin alphaIIbbeta3 (glycoprotein IIb/IIIa) to interact with components of the subendothelial matrix, such as fibronectin (Fn), exposed at sites of vascular injury. Studies using synthetic peptides derived from human Fn sequences Asp(1373)-Thr(1383) and Arg(1493)-Asp(1495) have suggested a role for both the 9th (3fn9) and 10th (3fn10) type III repeats of this ligand in binding to alphaIIbbeta3. In this study, we have taken a charge-to-alanine mutagenesis approach to evaluate the importance of these sites, and other charged residues, within the context of recombinant 3fn9-10 modules for binding to alphaIIbbeta3. To identify residues that are involved in Fn binding to alphaIIbbeta3, recombinantly expressed 3fn9-10 module pairs with alanine substitutions introduced into each of the 38 charged residues were individually assayed for the ability to inhibit Fn binding to purified alphaIIbbeta3. Substitutions at Fn residues Arg(1493) and Asp(1495) of the RGD sequence were found to have the greatest effect on alphaIIbbeta3 binding, as expected. However, Fn residues Arg(1369), Arg(1371), Arg(1379), Arg(1445), and Arg(1448) were needed for optimal interaction of the 3fn9-10 module pair with alphaIIbbeta3. All Fn residues found to affect binding of 3fn9-10 to alphaIIbbeta3 are located on the same face and extend from the surface of the molecule. Additionally, the epitopes for two anti-Fn monoclonal antibodies that inhibit binding of this ligand to alphaIIbbeta3 were found to overlap the sites identified. These results demonstrate that alphaIIbbeta3-Fn binding involves multiple electrostatic interactions. |
