CD5

Function

Lymphoid-specific receptor expressed by all T-cells and in a subset of B-cells known as B1a cells. Plays a role in the regulation of TCR and BCR signaling, thymocyte selection, T-cell effector differentiation and immune tolerance. Acts by interacting with several ligands expressed on B-cells such as CD5L or CD72 and thereby plays an important role in contact-mediated, T-dependent B-cell activation and in the maintenance of regulatory T and B-cell homeostasis. Functions as a negative regulator of TCR signaling during thymocyte development by associating with several signaling proteins including LCK, CD3Z chain, PI3K or CBL (PubMed:1384049, PubMed:1385158). Mechanistically, co-engagement of CD3 with CD5 enhances phosphorylated CBL recruitment leading to increased VAV1 phosphorylation and degradation (PubMed:23376399). Modulates B-cell biology through ERK1/2 activation in a Ca(2+)-dependent pathway via the non-selective Ca(2+) channel TRPC1, leading to IL-10 production (PubMed:27499044).

Post-translational modifications

Phosphorylated on serine, threonine and tyrosine residues following TCR stimulation (PubMed:1385158). Phosphorylated by LCK on Tyr-453 and Tyr-487 upon TCR engagement.

Cellular localization

• Cell membrane
• Single-pass type I membrane protein

Alternative names

CD5, LEU1, T-cell surface glycoprotein CD5, Lymphocyte antigen T1/Leu-1

Database links

swissprot:P06127 omim:153340 entrezGene:921 entrezGene:931 swissprot:P11836 omim:112210