Editing CD32 (section)

{{short description|Surface receptor glycoprotein}}
{{about|the molecule|the video game console|Amiga CD32}}

{{infobox protein
|Name= [[FCGR2A|Fc fragment of IgG, low affinity IIa, receptor (CD32)]]
|caption=
|image=
|width=
|HGNCid=3616
|Symbol=[[FCGR2A]]
|AltSymbols=FCG2, FCGR2A1, FCGR2
|EntrezGene=2212
|OMIM=146790
|RefSeq=NM_021642
|UniProt=P12318
|PDB=
|ECnumber=
|Chromosome=1
|Arm=q
|Band=23
|LocusSupplementaryData=
}}
{{infobox protein
|Name= [[FCGR2B|Fc fragment of IgG, low affinity IIb, receptor (CD32)]]
|caption=Crystal structure of the human fcgamma-receptor IIb ectodomain (CD32).<ref name="pmid10064577">{{PDB|2FCB}}; {{cite journal | vauthors = Sondermann P, Huber R, Jacob U | title = Crystal structure of the soluble form of the human fcgamma-receptor IIb: a new member of the immunoglobulin superfamily at 1.7 A resolution | journal = The EMBO Journal | volume = 18 | issue = 5 | pages = 1095–103 | date = March 1999 | pmid = 10064577 | pmc = 1171201 | doi = 10.1093/emboj/18.5.1095 }}; rendered via [http://pymol.sourceforge.net PyMOL].</ref>
|image=CD32ray.png
|width=
|HGNCid=3618
|Symbol=[[FCGR2B]]
|AltSymbols=FCG2, FCGR2
|EntrezGene=2213
|OMIM=604590
|RefSeq=NM_004001
|UniProt=P31994
|PDB=
|ECnumber=
|Chromosome=1
|Arm=q
|Band=23
|LocusSupplementaryData=
}}
{{infobox protein
|Name=Fc fragment of IgG, low affinity IIc, receptor for (CD32)
|caption=
|image=
|width=
|HGNCid=15626
|Symbol=FCGR2C
|AltSymbols=
|EntrezGene=9103
|OMIM=
|RefSeq=NM_201563
|UniProt=P31995
|PDB=
|ECnumber=
|Chromosome=1
|Arm=q
|Band=23
|LocusSupplementaryData=
}}
'''CD32''' ('''c'''luster of '''d'''ifferentiation 32), also known as '''FcγRII''' or '''FCGR2''', is a surface receptor [[glycoprotein]] belonging to the Ig gene superfamily.<ref name=":0">{{cite journal | vauthors = Lisi S, Sisto M, Lofrumento DD, D'Amore S, D'Amore M | title = Advances in the understanding of the Fc gamma receptors-mediated autoantibodies uptake | journal = Clinical and Experimental Medicine | volume = 11 | issue = 1 | pages = 1–10 | date = March 2011 | pmid = 20454994 | doi = 10.1007/s10238-010-0098-1 | s2cid = 6748965 }}</ref> CD32 can be found on the surface of a variety of immune cells.<ref name=":0" /><ref name=":1">{{cite journal | vauthors = Anania JC, Chenoweth AM, Wines BD, Hogarth PM | title = The Human FcγRII (CD32) Family of Leukocyte FcR in Health and Disease | language = English | journal = Frontiers in Immunology | volume = 10 | pages = 464 | date = 2019 | pmid = 30941127 | pmc = 6433993 | doi = 10.3389/fimmu.2019.00464 | doi-access = free }}</ref> CD32 has a low-affinity for the [[Fragment crystallizable region|Fc region]] of [[Immunoglobulin G|IgG]] antibodies in monomeric form, but high affinity for IgG [[immune complex]]es.<ref name=":3">{{cite journal | vauthors = Hamzeh-Cognasse H, Damien P, Chabert A, Pozzetto B, Cognasse F, Garraud O | title = Platelets and infections - complex interactions with bacteria | journal = Frontiers in Immunology | volume = 6 | pages = 82 | date = 2015-02-26 | pmid = 25767472 | pmc = 4341565 | doi = 10.3389/fimmu.2015.00082 | doi-access = free }}</ref> CD32 has two major functions: cellular response regulation, and the uptake of immune complexes.<ref name=":0" /> Cellular responses regulated by CD32 include [[phagocytosis]], [[cytokine]] stimulation, and [[Endocytosis|endocytic transport]].<ref name=":1" /> Dysregulated CD32 is associated with different forms of [[autoimmunity]], including [[systemic lupus erythematosus]].<ref name=":2">{{cite journal | vauthors = Smith KG, Clatworthy MR | title = FcgammaRIIB in autoimmunity and infection: evolutionary and therapeutic implications | journal = Nature Reviews. Immunology | volume = 10 | issue = 5 | pages = 328–43 | date = May 2010 | pmid = 20414206 | pmc = 4148599 | doi = 10.1038/nri2762 }}</ref> In humans, there are three major CD32 subtypes: CD32A, CD32B, and CD32C. While CD32A and CD32C are involved in activating cellular responses, CD32B is inhibitory.<ref name=":1" />