The effects of cysteine to alanine mutations of CD18 on the expression andadhesion of the CD11/CD18 integrins

Of the 56 cysteines in the extracellular domain of the CD18 antigen (beta2 integrin subunit), corresponding ones are not found in 12 positions in the beta4, beta7, or beta8 integrin subunits. These 12 cysteines were mutated t o alanines, either singly or in pairs, in CD18. All these mutants can suppo rt the expression of all three CD11/CD18 integrins. Transfectants expressin g these variant integrins are generally more adhesive than the wild-type, s uggesting that the cysteine residues, perhaps by engaging in disulphide bon ds, may contribute to the maintenance of the CD11/CD18 integrins in a resti ng state. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.