CD32; low affinity immunoglobulin gamma Fc region receptor II-b; IgG Fc receptor II-b; Fc-gamma RII-b; Fc-gamma-RIIb; FcRII-b; CDw32 (FCGR2B, FCG2, IGFR2)

^[1]^[2]^[3]

Function

receptor for the Fc region of complexed or aggregated IgG, low affinity receptor
involved in a variety of effector & regulatory functions including:
- phagocytosis of immune complexes
- modulation of antibody production by B-cells
binding to CD32 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
FCGR2B is the only receptor for IgG Fc domains detectable on the surface of B-cells^[2]
coligation of the Fc receptor on B-cells & the B-cell antigen receptor by immune complexes leads to abortive B-cell antigen receptor signalling
this occurs as a result of recruitment & activation of protein tyrosine phosphatase PTP1C by the activated Fc receptor.
Tyr phosphorylation of the Fc receptor leads to binding of PTP1C to the Fc receptor^[3]

isoform IIB1 interacts with measles virus N protein
- N protein is released in the blood following lysis of measles infected cells
- this interaction presumably blocks inflammatory immune response
chromosomal translocation t(1;22)(q22;q11) involving FCGR2B is found in a follicular lymphoma; the translocation leads to the hyperexpression of the receptor; this may play a role in the tumor progression

↑ UniProt http://www.uniprot.org/uniprot/P31994.html
↑ ^2.0 ^2.1 Atlas of genetics & cytogenetics in oncology & haematology http://atlasgeneticsoncology.org/genes/FCGR2BID397.html
↑ ^3.0 ^3.1 D'Ambrosio D et al, Recruitment and activation of PTP1C in negative regulation of antigen receptor signaling by Fc gamma RIIB1. Science. 1995 Apr 14;268(5208):293-7. PMID: https://www.ncbi.nlm.nih.gov/pubmed/7716523