Fcγ receptor IIb
| Fcγ receptor IIb | ||
|---|---|---|
|
||
| according to PDB 1FCG | ||
| other names |
CDw32, Fc-gamma RII-b, Fc-gamma-RIIb, FcRII-b, Low affinity immunoglobulin gamma Fc region receptor II-b |
|
| Properties of human protein | ||
| Mass / length primary structure | 310 amino acids , 34,044 Da | |
| Identifier | ||
| External IDs | ||
Fcγ receptor IIb (synonym CD32b ) is a surface protein from the group of Fc receptors .
properties
The Fcγ receptor IIb serves as an inhibitory receptor for immunoglobulin G in the immune system and binds it with low affinity . After binding, it initiates phagocytosis and is involved in the antigen presentation via MHC II . The Fcγ receptor IIb is produced by different haematopoietic cells (but not in NK cells ), with differences between the isoforms . Isoform IIb1 is mainly formed by lymphoid cells, IIb2 by myeloid cells, IIb3 is released into the blood serum by macrophages . Isoform IIb1 'is produced in mice by myeloid and lymphoid cells, splenocytes and resting or LPS- activated B cells , but not by mesenteric cells in lymph nodes. The isoforms IIb1 and IIb2 do not induce phagocytosis. IIb2 initiates clathrin-mediated endocytosis of immune complexes . IIb1 and IIb2 reduce the ability of B cells, T cells and mast cells to be activated if they bind to the B cell receptor , the T cell receptor and an Fc receptor, respectively. The inhibitory ITIM motif lies on the intracellular side of the cell membrane .
Web links
Individual evidence
- ↑ M. Espéli, KG Smith, MR Clatworthy: FcγRIIB and autoimmunity. In: Immunological reviews. Volume 269, Number 1, January 2016, pp. 194-211, doi : 10.1111 / imr.12368 , PMID 26683154 .
- ^ S. Aschermann, A. Lux, A. Baerenwaldt, M. Biburger, F. Nimmerjahn: The other side of immunoglobulin G: suppressor of inflammation. In: Clinical and experimental immunology. Volume 160, number 2, May 2010, pp. 161-167, doi : 10.1111 / j.1365-2249.2009.04081.x , PMID 20041883 , PMC 2857938 (free full text).