Fc-activating receptor

Fc-activating receptors are cell-surface immune receptors that bind the Fc region of immunoglobulins (antibodies), especially IgG (via Fc gamma receptors). These activating Fc receptors (for example, FcγRI, FcγRIIA, FcγRIIIA, FcεRI) are expressed on multiple immune cells including macrophages, neutrophils, NK cells, and dendritic cells. Upon binding antibodies—especially when clustered by immune complexes—they trigger cellular activation via immunoreceptor tyrosine-based activation motifs (ITAMs), leading to diverse effector functions such as phagocytosis, ADCC, cytokine release, and degranulation. Clinically, engaging activating Fc receptors is critical for the mechanisms of action of many therapeutic antibodies, and polymorphisms in Fc receptor genes can affect patient outcomes. The term “Fc-activating receptor” does not refer to a single molecule and should be resolved to a specific receptor subtype for precision.

Other names

FcRactivating Fc receptorimmunoglobulin Fc receptor

Antibody-dependent cell-mediated cytotoxicity (ADCC); Antibody-dependent cellular phagocytosis (ADCP); Modulation of inflammatory signaling via FcR crosslinking