Search
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)
Function:
- receptor for the Fc region of complexed or aggregated IgG, low affinity receptor
- involved in a variety of effector & regulatory functions including:
a) phagocytosis of immune complexes
b) 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]
Structure:
- contains 1 ITIM motif
- contains 2 Ig-like C2-type domain (immunoglobulin-like)
Compartment: cell membrane
Alternative splicing: named isoforms=3
Expression:
- most broadly distributed Fc-gamma-receptor
- expressed in monocyte, neutrophils, macrophages, basophils, eosinophils, Langerhans cells, B-cells, platelets cells & placenta (endothelial cells)
- not detected in natural killer cells
Pathology:
- isoform IIB1 interacts with measles virus N protein
a) N protein is released in the blood following lysis of measles infected cells
b) 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
General
CD32 or Fc gamma [IgG] receptor-II (low affinity)
glycoprotein
Properties
SIZE: entity length = 310 aa
MW = 34 kD
COMPARTMENT: cellular membrane
MOTIF: signal sequence {1-42}
immunoglobulin superfamily domain {48-127}
MOTIF: cysteine residue {C71}
MODIFICATION: cysteine residue {C113}
N-glycosylation site {N106}
cysteine residue {C113}
MODIFICATION: cysteine residue {C71}
immunoglobulin superfamily domain {131-213}
MOTIF: cysteine residue {C152}
MODIFICATION: cysteine residue {C196}
N-glycosylation site {N180}
N-glycosylation site {N187}
cysteine residue {C196}
MODIFICATION: cysteine residue {C152}
transmembrane domain {218-240}
immunoreceptor tyrosine-based inhibitory motif (ITIM) {290-295}
Database Correlations
OMIM 604590
MORBIDMAP 604590
UniProt P31994
Pfam PF00047
Kegg hsa:2213
References
- UniProt :accession P31994
- Atlas of genetics & cytogenetics in oncology & haematology
http://atlasgeneticsoncology.org/genes/FCGR2BID397.html
- 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: 7716523