CD4

The Ig-like V-type domain mediates the interaction with MHCII.

Integral membrane glycoprotein that plays an essential role in the immune response and serves multiple functions in responses against both external and internal offenses. In T-cells, functions primarily as a coreceptor for MHC class II molecule:peptide complex. The antigens presented by class II peptides are derived from extracellular proteins while class I peptides are derived from cytosolic proteins. Interacts simultaneously with the T-cell receptor (TCR) and the MHC class II presented by antigen presenting cells (APCs). In turn, recruits the Src kinase LCK to the vicinity of the TCR-CD3 complex. LCK then initiates different intracellular signaling pathways by phosphorylating various substrates ultimately leading to lymphokine production, motility, adhesion and activation of T-helper cells. In other cells such as macrophages or NK cells, plays a role in differentiation/activation, cytokine expression and cell migration in a TCR/LCK-independent pathway. Participates in the development of T-helper cells in the thymus and triggers the differentiation of monocytes into functional mature macrophages.

Palmitoylation and association with LCK contribute to the enrichment of CD4 in lipid rafts.

Phosphorylated by PKC; phosphorylation plays an important role for CD4 internalization.

Highly expressed in T-helper cells. The presence of CD4 is a hallmark of T-helper cells which are specialized in the activation and growth of cytotoxic T-cells, regulation of B cells, or activation of phagocytes. CD4 is also present in other immune cells such as macrophages, dendritic cells or NK cells.

• Cell membrane
• Single-pass type I membrane protein

CD4, T-cell surface glycoprotein CD4, T-cell differentiation antigen L3T4, T-cell surface antigen T4/Leu-3, Cd4

• entrezGene:12504
• swissprot:P06332

Proteins

Immunology & Infectious Disease

51297Da