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: cell surface; endoplasmic reticulum lumen; endoplasmic reticulum membrane; external side of plasma membrane; integral component of membrane; integral component of plasma membrane; membrane; membrane raft; plasma membrane
Molecular Function: coreceptor activity; enzyme binding; 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; zinc ion binding
Biological Process: adaptive immune response; cell adhesion; cell surface receptor signaling pathway; cytokine production; defense response to Gram-negative bacterium; immune response; immune system process; 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 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 activation; 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 T cell activation; T cell activation; T cell differentiation; T cell selection