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: clathrin-coated vesicle membrane; early endosome; endoplasmic reticulum lumen; endoplasmic reticulum membrane; external side of plasma membrane; integral component of plasma membrane; membrane raft; plasma membrane; T cell receptor complex
Molecular Function: coreceptor activity; enzyme binding; extracellular matrix structural constituent; identical protein binding; immunoglobulin binding; interleukin-16 binding; interleukin-16 receptor activity; MHC class II protein binding; protein binding; protein homodimerization activity; protein kinase binding; receptor activity; transmembrane receptor activity; viral receptor activity; zinc ion binding
Biological Process: adaptive immune response; cell adhesion; cell surface receptor signaling pathway; cytokine production; defense response to Gram-negative bacterium; entry into host cell; enzyme linked receptor protein signaling pathway; fusion of virus membrane with host plasma membrane; immune response; induction by virus of host cell-cell fusion; maintenance of cellular protein localization; positive regulation of calcium-mediated signaling; positive regulation of I-kappaB kinase/NF-kappaB signaling; positive regulation of interleukin-2 biosynthetic process; positive regulation of kinase activity; positive regulation of MAPK cascade; positive regulation of monocyte differentiation; positive regulation of peptidyl-tyrosine phosphorylation; positive regulation of protein kinase activity; positive regulation of protein phosphorylation; positive regulation of T cell proliferation; positive regulation of transcription, DNA-templated; positive regulation of virion penetration into host cell; regulation of calcium ion transport; regulation of defense response to virus by virus; regulation of T cell activation; response to estradiol; response to vitamin D; signal transduction; T cell costimulation; T cell differentiation; T cell receptor signaling pathway; T cell selection; transmembrane receptor protein tyrosine kinase signaling pathway