ICAM-1

ICAM-1 (Intercellular Adhesion Molecule 1) also known as CD54 (Cluster of Differentiation 54) is a protein that in humans is encoded by the ICAM1 gene. This gene encodes a cell surface glycoprotein which is typically expressed on endothelial cells and cells of the immune system. It binds to integrins of type CD11a / CD18, or CD11b / CD18 and is also exploited by rhinovirus as a receptor.

Structure

ICAM-1 is a member of the immunoglobulin superfamily, the superfamily of proteins including antibodies and T-cell receptors. ICAM-1 is a transmembrane protein possessing an amino-terminus extracellular domain, a single transmembrane domain, and a carboxy-terminus cytoplasmic domain. The structure of ICAM-1 is characterized by heavy glycosylation, and the protein’s extracellular domain is composed of multiple loops created by disulfide bridges within the protein. The dominant secondary structure of the protein is the beta sheet, leading researchers to hypothesize the presence of dimerization domains within ICAM-1.