Binds to the Fc region of immunoglobulins gamma. Low affinity receptor. By binding to IgG it initiates cellular responses against pathogens and soluble antigens. Promotes phagocytosis of opsonized antigens (By similarity). Interacts with INPP5D/SHIP1 and INPPL1/SHIP2, regulating its function. Interacts with APCS and FGR. Interacts with HCK (By similarity). Phosphorylated by SRC-type Tyr-kinases such as HCK, LYN, BLK, FYN and SYK.