Receptor for the invariable Fc fragment of immunoglobulin gamma (IgG) (By similarity). Optimally activated upon binding of clustered antigen-IgG complexes displayed on cell surfaces, triggers lysis of antibody-coated cells, a process known as antibody-dependent cellular cytotoxicity (ADCC). Does not bind free monomeric IgG, thus avoiding inappropriate effector cell activation in the absence of antigenic trigger. Mediates IgG effector functions on natural killer (NK) cells. Binds antigen-IgG complexes generated upon infection and triggers NK cell-dependent cytokine production and degranulation to limit viral load and propagation (By similarity). Fc-binding subunit that associates with FCER1G adapter to form functional signaling complexes. Following the engagement of antigen-IgG complexes, triggers phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM)-containing adapters with subsequent activation of phosphatidylinositol 3-kinase signaling and sustained elevation of intracellular calcium that ultimately drive NK cell activation (By similarity). Mediates enhanced ADCC in response to afucosylated IgGs (PubMed:34485821). Forms a heterooligomeric complex with ITAM-containing signaling subunits FCER1G. Interacts (via transmembrane domain) with signaling subunits; this interaction is a prerequisite for receptor complex expression on the cell surface and intracellular signal transduction. Binds the Fc region of antigen-complexed IgG.