The role of the cysteine-rich region of the β2 integrin subunit in the leukocyte function-associated antigen-1 (LFA-1, αLβ2, CD11a/CD18) heterodimer formation and ligand binding

The cysteine-rich region (CRR) of the beta 2 integrin subunit was replaced by that of pi to give the chimera beta 2NV1. beta 2NV1 can combine with alpha L to form a variant leukocyte-function-associated antigen (LFA)-1 on COS cell surface, suggesting that the specificity of the beta 2 interaction with at does not lie in the CRR, Unlike those expressing wild-type LFA-1, COS cells expressing alpha L beta 2NV1 are constitutively active in intercellular adhesion molecule (ICAM)-1 adhesion. These results suggest that activation of LFA-I involves the release of an intramolecular constraint, which is maintained, in part, by the authentic beta 2 CRR, (C) 1998 Federation of European Biochemical Societies.