CD72

CD72, also known as B lymphocyte antigen CD72, is a transmembrane glycoprotein expressed predominantly on B cells in humans and other vertebrates. It is a cell-surface receptor that serves as a regulatory co-receptor for B cell receptor (BCR) signaling and is commonly used as a phenotypic marker for B cells in flow cytometry and immunohistochemistry.

The protein comprises an extracellular region with immunoglobulin-like domains, a single-pass transmembrane segment, and a cytoplasmic tail containing tyrosine-based motifs that can be phosphorylated. These motifs recruit phosphatases such as SHP-1, enabling attenuation of BCR signaling.

Through ITIM-mediated recruitment of SHP-1, CD72 modulates B cell activation thresholds, contributes to tolerance by dampening excessive B cell responses, and influences differentiation into antibody-secreting cells.

The extracellular domain binds to sialylated glycans on glycoconjugates, enabling recognition of glycan ligands. It can participate in cis or trans interactions, and may interact with other B cell surface receptors to shape signaling.

CD72 expression patterns are used to characterize B cell populations in research and clinical settings. Altered CD72 expression or signaling has been implicated in autoimmune diseases and B cell malignancies in some studies, and researchers have explored CD72 as a potential target for therapies aiming to modulate B cell activity.

The CD72 gene is conserved across mammals and encodes the CD72 protein.