| First Author | Kamata T | Year | 1995 |
| Journal | J Biol Chem | Volume | 270 |
| Issue | 21 | Pages | 12531-5 |
| PubMed ID | 7539004 | Mgi Jnum | J:25636 |
| Mgi Id | MGI:73350 | Doi | 10.1074/jbc.270.21.12531 |
| Citation | Kamata T, et al. (1995) Critical threonine and aspartic acid residues within the I domains of beta 2 integrins for interactions with intercellular adhesion molecule 1 (ICAM-1) and C3bi. J Biol Chem 270(21):12531-5 |
| abstractText | Integrins mediate signal transduction through interactions with multiple cellular or extracellular matrix ligands. Evidence is accumulating that the I (or A) domain, a approximately 200-residue inserted sequence in some integrin alpha subunits, mediates ligand binding. We have previously shown that Thr-221 of the putative ligand binding sites within alpha 2 I domain of alpha 2 beta 1 is critical for binding to collagen (Kamata, T., and Takada, Y. (1994) J. Biol. Chem. 269, 26006-26010). Here we report that the mutation of Thr-206 of alpha L blocks intercellular adhesion molecule 1 (ICAM-1) binding to alpha L beta 2 and mutation of Thr-209 of alpha M blocks ICAM-1 and C3bi binding to alpha M beta 2. The data indicate the Thr residues of alpha M and alpha L corresponding to Thr-221 of alpha 2 are critically involved in the ligand interaction with beta 2 integrins. The mutations of the Asp-137 and Asp-239 of alpha L also block ICAM-1 binding to alpha L beta 2, as do the corresponding Asp residues of alpha 2 or alpha M in collagen/alpha 2 beta 1 or C3bi/alpha M beta 2 interactions, respectively. These data suggest that these Thr and Asp residues, conserved among I domains, are critical for interaction with structurally distinct ligands (e.g. ICAMs, C3bi, and collagen). |
