FCGR3

This gene encodes a receptor for the Fc portion of immunoglobulin G, and it is involved in the removal of antigen-antibody complexes from the circulation, as well as other other antibody-dependent responses. This gene (FCGR3A) is highly similar to another nearby gene (FCGR3B) located on chromosome 1. The receptor encoded by this gene is expressed on natural killer (NK) cells as an integral membrane glycoprotein anchored through a transmembrane peptide, whereas FCGR3B is expressed on polymorphonuclear neutrophils (PMN) where the receptor is anchored through a phosphatidylinositol (PI) linkage. Mutations in this gene have been linked to susceptibility to recurrent viral infections, susceptibility to systemic lupus erythematosus, and alloimmune neonatal neutropenia. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.

Full Name

Fc Fragment Of IgG Receptor IIIa

Research Area

Receptor for the Fc region of IgG. Binds complexed or aggregated IgG and also monomeric IgG. Mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis.

Biological Process

Cell surface receptor signaling pathway Source: GO_Central
Immune response Source: ProtInc
Regulation of immune response Source: GO_Central

Cellular Location

Secreted; Cell membrane. Exists also as a soluble receptor.

Involvement in disease

Immunodeficiency 20 (IMD20):
A rare autosomal recessive primary immunodeficiency characterized by functional deficiency of NK cells. Affected individuals typically present with severe herpes viral infections, particularly Epstein Barr virus (EBV), and human papillomavirus (HPV).

Topology

Extracellular: 17-208
Helical: 209-229
Cytoplasmic: 230-254

PTM

Glycosylated. Contains high mannose- and complex-type oligosaccharides. Glycosylation at Asn-180 is mandatory for high affinity binding to the Fc and for discrimination between fucosylated and afucosylated IgG glycoforms.
The soluble form is produced by a proteolytic cleavage.