Binding of the integrin Mac-1 (CD11b/CD18) to the third immunoglobulin-like domain of ICAM-1 (CD54) and its regulation by glycosylation.
Both the integrins LFA-1 and Mac-1 bind to ICAM-1, an immunoglobulin superfamily member. Previously, we localized the binding sites of LFA-1 and the major group of human rhinoviruses to the first NH2-terminal immunoglobulin-like domain of ICAM-1. Here, we show that the binding site on ICAM-1 for Mac-1 is unexpectedly distinct from that for LFA-1 and maps to the third NH2-terminal immunoglobulin-like domain. These findings provide a function for the tandem duplication of immunoglobulin-like domains in ICAM-1 and have implications for other immunoglobulin superfamily members. Mutations at two sites in the third domain that destroy consensus sequences for N-linked glycosylation enhance binding to purified Mac-1. Agents that interfere with carbohydrate processing provide evidence that the size of the N-linked oligosaccharide side chains on ICAM-1 affects binding to Mac-1 but not to LFA-1. Thus, we suggest that the extent of glycosylation on ICAM-1 may regulate adhesion to LFA-1 or Mac-1 in vivo.
Committee on Cell & Developmental Biology, Harvard Medical School, Boston, Massachusetts 02115.
M S
MS
Diamond
D E
DE
Staunton
S D
SD
Marlin
T A
TA
Springer
D000595:Amino Acid Sequence; D001665:Binding Sites; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D004252:DNA Mutational Analysis; D006023:Glycoproteins / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D066298:In Vitro Techniques; D018799:Intercellular Adhesion Molecule-1; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D016177:Macrophage-1 Antigen / Q000378:metabolism*; D009504:Neutrophils / Q000166:cytology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship
D015815:Cell Adhesion Molecules; D006023:Glycoproteins; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1