CD64

{{short description|Integral membrane glycoprotein}} {{infobox protein |Name= Fc fragment of IgG, high affinity Ia, receptor (CD64) |caption= |image= |width= |HGNCid=3613 |Symbol=FCGR1A |AltSymbols= |EntrezGene=2209 |OMIM=146760 |RefSeq=NM_000566 |UniProt=P12314 |PDB= |ECnumber= |Chromosome=1 |Arm=q |Band=21.2 |LocusSupplementaryData=-21.3 }} {{infobox protein |Name=Fc fragment of IgG, high affinity Ib, receptor (CD64) |caption= |image= |width= |HGNCid=3614 |Symbol=FCGR1B |AltSymbols= |EntrezGene=2210 |OMIM=601502 |RefSeq=NM_001004340 |UniProt=Q92637 |PDB= |ECnumber= |Chromosome=1 |Arm=p |Band=11.2 |LocusSupplementaryData= }} {{infobox protein |Name=Fc fragment of IgG, high affinity Ic, receptor (CD64) |caption= |image= |width= |HGNCid=3615 |Symbol=FCGR1C |AltSymbols= |EntrezGene=2211 |OMIM=601503 |RefSeq=XM_001133198 |UniProt= |PDB= |ECnumber= |Chromosome=1 |Arm=q |Band=21.1 |LocusSupplementaryData= }} '''CD64''' ('''C'''luster of '''D'''ifferentiation '''64''') is a type of integral membrane glycoprotein known as an Fc receptor that binds monomeric IgG-type antibodies with high affinity.<ref>{{cite journal |vauthors=Hulett M, Hogarth P |title=The second and third extracellular domains of FcgammaRI (CD64) confer the unique high affinity binding of IgG2a |journal=Mol Immunol |volume=35 |issue=14–15 |pages=989–96 |year=1998 |pmid=9881694 |doi=10.1016/S0161-5890(98)00069-8}}</ref> It is more commonly known as Fc-gamma receptor 1 (FcγRI). After binding IgG, CD64 interacts with an accessory chain known as the common γ chain (γ chain), which possesses an ITAM motif that is necessary for triggering cellular activation.<ref>{{cite journal |vauthors=Nimmerjahn F, Ravetch J |title=Fcgamma receptors: old friends and new family members |journal=Immunity |volume=24 |issue=1 |pages=19–28 |year=2006 |pmid=16413920 |doi=10.1016/j.immuni.2005.11.010|doi-access=free }}</ref>

Structurally CD64 is composed of a signal peptide that allows its transport to the surface of a cell, three extracellular immunoglobulin domains of the C2-type that it uses to bind antibody, a hydrophobic transmembrane domain, and a short cytoplasmic tail.<ref name="Ernst L, Duchemin A, Miller K, Anderson C 1998 943–54">{{cite journal |vauthors=Ernst L, Duchemin A, Miller K, Anderson C |title=Molecular characterization of six variant Fcgamma receptor class I (CD64) transcripts |journal=Mol Immunol |volume=35 |issue=14–15 |pages=943–54 |year=1998 |doi=10.1016/s0161-5890(98)00079-0 |pmid=9881690}}</ref>

CD64 is constitutively found on only macrophages and monocytes, but treatment of polymorphonuclear leukocytes with cytokines like IFNγ and G-CSF can induce CD64 expression on these cells.<ref>{{cite journal |vauthors=Perussia B, Dayton E, Lazarus R, Fanning V, Trinchieri G |title=Immune interferon induces the receptor for monomeric IgG1 on human monocytic and myeloid cells |journal=J Exp Med |volume=158 |issue=4 |pages=1092–113 |year=1983 |pmid=6225822 |doi=10.1084/jem.158.4.1092 |pmc=2187379}}</ref><ref>{{cite journal |vauthors=Repp R, Valerius T, Sendler A, Gramatzki M, Iro H, Kalden J, Platzer E |title=Neutrophils express the high affinity receptor for IgG (Fc gamma RI, CD64) after in vivo application of recombinant human granulocyte colony-stimulating factor |journal=Blood |volume=78 |issue=4 |pages=885–9 |year=1991 |doi=10.1182/blood.V78.4.885.885 |pmid=1714327|doi-access=free }}</ref>

There are three distinct (but highly similar) genes in humans for CD64 called FcγRIA (CD64A), FcγRIB (CD64B), and FcγRIC (CD64C) that are located on chromosome 1.<ref>{{cite journal |vauthors=Ernst L, van de Winkel J, Chiu I, Anderson C |title=Three genes for the human high affinity Fc receptor for IgG (Fc gamma RI) encode four distinct transcription products |journal=J Biol Chem |volume=267 |issue=22 |pages=15692–700 |year=1992 |doi=10.1016/S0021-9258(19)49591-4 |pmid=1379234|doi-access=free }}</ref> These three genes produce six different mRNA transcripts; two from CD64A, three from CD64B, and one from CD64C; by alternate splicing.<ref name="Ernst L, Duchemin A, Miller K, Anderson C 1998 943–54" />

==References== {{reflist}}

==External links== * {{MeshName|CD64+Antigens}}

{{Clusters of differentiation}} {{Clusters of differentiation by lineage}} {{Immune receptors}}

Category:Clusters of differentiation Category:Fc receptors