Receptor for the Fc region of complexed or aggregated immunoglobulins gamma. Low affinity receptor. Involved in a variety of effector and regulatory functions such as phagocytosis of immune complexes and modulation of antibody production by B-cells. Binding to this receptor results in down-modulation of previous state of cell activation triggered via antigen receptors on B-cells (BCR), T-cells (TCR) or via another Fc receptor. Isoform IIB1 fails to mediate endocytosis or phagocytosis. Isoform IIB2 does not trigger phagocytosis. Interacts with INPP5D/SHIP1. Interacts with FGR. Interacts with LYN. (Microbial infection) Isoform IIB1 interacts with measles virus protein N. Protein N is released in the blood following lysis of measles infected cells. This interaction presumably block inflammatory immune response. Is the most broadly distributed Fc-gamma-receptor. Expressed in monocyte, neutrophils, macrophages, basophils, eosinophils, Langerhans cells, B-cells, platelets cells and placenta (endothelial cells). Not detected in natural killer cells. Contains 1 copy of a cytoplasmic motif that is referred to as the immunoreceptor tyrosine-based inhibitor motif (ITIM). This motif is involved in modulation of cellular responses. The phosphorylated ITIM motif can bind the SH2 domain of several SH2-containing phosphatases. Phosphorylated by the SRC-type Tyr-kinases LYN and BLK. FCGR2B polymorphisms can influence susceptibility or resistance to malaria [MIM:611162]. Disease susceptibility is associated with variants affecting the gene represented in this entry. Has sometimes been attributed to correspond to FcR-IIC. Truncated N-terminus.