ICAM proteins are ligands for the leukocyte adhesion protein LFA-1 (integrin alpha-L/beta-2). During leukocyte trans-endothelial migration, ICAM1 engagement promotes the assembly of endothelial apical cups through ARHGEF26/SGEF and RHOG activation. (Microbial infection) Acts as a receptor for major receptor group rhinovirus A-B capsid proteins. (Microbial infection) Acts as a receptor for Coxsackievirus A21 capsid proteins. (Microbial infection) Upon Kaposi's sarcoma-associated herpesvirus/HHV-8 infection, is degraded by viral E3 ubiquitin ligase MIR2, presumably to prevent lysis of infected cells by cytotoxic T-lymphocytes and NK cell. Homodimer (Probable). Interacts with MUC1 and promotes cell aggregation in epithelial cells. Interacts with ARHGEF26/SGEF. Interacts (on T cell side) with CD81, CD247 and CD9 at immunological synapses between antigen-presenting cells and T cells. (Microbial infection) Interacts with major receptor group rhinovirus A-B capsid proteins (PubMed:1968231, PubMed:2538243). (Microbial infection) Interacts with Coxsackievirus A21 capsid proteins (PubMed:11160747, PubMed:16004874, PubMed:9539703). Monoubiquitinated, which is promoted by MARCH9 and leads to endocytosis. Homozygotes with ICAM1-Kalifi Met-56 seem to have an increased risk for cerebral malaria [MIM:611162]. Belongs to the immunoglobulin superfamily. ICAM family. Intercellular adhesion molecule entry Icosahedral capsid structure ICAM-1