Recombinant human CD4 protein (Active)

Specifications

Form

Lyophilized

Additional notes

> 95% by HPLC analysis.

General info

Function

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.. (Microbial infection) Primary receptor for human immunodeficiency virus-1 (HIV-1) (PubMed : 12089508, PubMed : 16331979, PubMed : 2214026, PubMed : 9641677). Down-regulated by HIV-1 Vpu (PubMed : 17346169). Acts as a receptor for Human Herpes virus 7/HHV-7 (PubMed : 7909607).

Post-translational modifications

Palmitoylation and association with LCK contribute to the enrichment of CD4 in lipid rafts.. Phosphorylated by PKC; phosphorylation at Ser-433 plays an important role for CD4 internalization.