CD5 (protein)

CD5 (protein)

CD5 protein structure

CD5 is a protein that in humans is encoded by the CD5 gene. It is a member of the scavenger receptor cysteine-rich (SRCR) superfamily and is predominantly expressed in T cells and B cells, the cells involved in the immune response.

Structure[edit | edit source]

CD5 is a type I transmembrane glycoprotein. It is composed of a large extracellular domain, a transmembrane domain, and a cytoplasmic domain. The extracellular domain contains three scavenger receptor cysteine-rich (SRCR) domains, which are involved in protein-protein interactions.

Function[edit | edit source]

CD5 plays a crucial role in the immune response. It acts as a co-receptor in both T cells and B cells, modulating T cell receptor and B cell receptor signaling. This modulation can either enhance or inhibit the immune response, depending on the context. CD5 also plays a role in autoimmunity and cancer.

Clinical significance[edit | edit source]

Alterations in CD5 expression have been associated with various diseases. Overexpression of CD5 is observed in certain types of leukemia and lymphoma, and is used as a diagnostic marker for these diseases. Conversely, reduced CD5 expression is associated with autoimmune diseases such as rheumatoid arthritis and multiple sclerosis.