CD45RB

CD45RB is a specific isoform of the protein tyrosine phosphatase, CD45. It is encoded by the PTPRC gene in humans. CD45RB is expressed on the surface of T cells and plays a crucial role in T cell activation and function.

Structure of CD45RB

Structure

CD45RB is a transmembrane protein with an extracellular domain, a transmembrane domain, and a cytoplasmic domain. The extracellular domain contains two fibronectin type III repeats, which are involved in protein-protein interactions. The cytoplasmic domain contains two phosphatase domains, one of which is catalytically active.

Function

CD45RB is involved in the regulation of T cell receptor (TCR) signaling. It dephosphorylates the Src family kinases, Lck and Fyn, which are involved in TCR signaling. This dephosphorylation activates the kinases, leading to downstream signaling events that result in T cell activation.

In addition to its role in T cell activation, CD45RB also plays a role in T cell differentiation. High expression of CD45RB is associated with naive T cells, while low expression is associated with memory T cells.

Clinical significance

Alterations in CD45RB expression have been associated with various autoimmune diseases, including rheumatoid arthritis, multiple sclerosis, and inflammatory bowel disease. In animal models of these diseases, manipulation of CD45RB expression has been shown to affect disease progression.

See also

• CD45
• T cell receptor
• Autoimmune disease