Accessory protein for MHC class-II antigen/T-cell receptor interaction. May regulate T-cell activation. Induces the aggregation of lipid rafts. Associates with LCK. Binds to HIV-1 gp120 and to P4HB/PDI and upon HIV-1 binding to the cell membrane, is part of P4HB/PDI- CD4-CXCR4-gp120 complex. Interacts with HIV-1 Envelope polyprotein gp160 and protein Vpu. Interacts with Human Herpes virus 7 capsid proteins. Interacts with PTK2/FAK1; this interaction requires the presence of HIV-1 gp120. Note: This description may include information from UniProtKB.
Protein type: Cell surface; Membrane protein, integral
Cellular Component: T cell receptor complex; endoplasmic reticulum membrane; endoplasmic reticulum lumen; early endosome; integral to membrane; plasma membrane; external side of plasma membrane; lipid raft
Molecular Function: protein binding; protein homodimerization activity; transmembrane receptor activity; enzyme binding; zinc ion binding; extracellular matrix structural constituent; coreceptor activity; receptor activity; glycoprotein binding; protein kinase binding; MHC class II protein binding
Biological Process: maintenance of cellular protein localization; viral reproduction; positive regulation of interleukin-2 biosynthetic process; T cell selection; cytokine production; positive regulation of calcium-mediated signaling; signal transduction; defense response to Gram-negative bacterium; induction by virus of cell-cell fusion in host; T cell receptor signaling pathway; enzyme linked receptor protein signaling pathway; regulation of defense response to virus by virus; positive regulation of peptidyl-tyrosine phosphorylation; cell surface receptor linked signal transduction; positive regulation of protein kinase activity; T cell costimulation; protein palmitoleylation; innate immune response; immune response; entry into host cell; cell adhesion; transmembrane receptor protein tyrosine kinase signaling pathway; regulation of T cell activation; T cell differentiation
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.