CD93
Description
The CD93 (CD93 molecule) is a protein-coding gene located on chromosome 20.
CD93 (Cluster of Differentiation 93) is a protein encoded by the CD93 gene in humans. It is a C-type lectin transmembrane receptor involved in both cell-to-cell adhesion and host defense. CD93 belongs to the Group XIV C-Type lectin family, which includes endosialin (CD248), CLEC14A, and thrombomodulin. All members of this family have a C-type lectin domain, several epidermal growth factor-like domains, a heavily glycosylated mucin-like domain, a unique transmembrane domain, and a short cytoplasmic tail. Due to their strong similarities and close proximity on chromosome 20, CD93 is thought to have originated from the thrombomodulin gene through a duplication event. CD93 was first identified in mice as a marker for early B cells using the AA4.1 monoclonal antibody. It was later shown to be expressed on early hematopoietic stem cells, which give rise to all mature blood cells. Now, CD93 is known to be expressed on a wide range of cells including platelets, monocytes, microglia, and endothelial cells. Within the immune system, CD93 is also expressed on neutrophils, activated macrophages, B cell precursors until the T2 stage in the spleen, a subset of dendritic cells, and some natural killer cells. Molecular characterization of CD93 revealed that it is identical to C1qRp, a human protein identified as a potential C1q receptor.
CD93 acts as a receptor (or part of a larger receptor complex) for C1q, mannose-binding lectin (MBL2), and pulmonary surfactant protein A (SPA). It might contribute to increased phagocytosis in monocytes and macrophages when it binds to soluble defense collagens. CD93 may also be involved in cell-to-cell adhesion.
CD93 is also known as C1QR1, C1qR(P), C1qRP, CDw93, ECSM3, MXRA4, dJ737E23.1.
