CD64 (biology)

protein
Name= Fc fragment of IgG, high affinity Ia, receptor (CD64)
caption=


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=-21.3protein
Name=Fc fragment of IgG, high affinity Ib, receptor (CD64)
caption=


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=protein
Name=Fc fragment of IgG, high affinity Ic, receptor (CD64)
caption=


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 (Cluster of Differentiation 64) is a type of integral membrane glycoprotein known as an Fc receptor that binds monomeric IgG-type antibodies with high affinity. [cite journal |author=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] 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. [cite journal |author=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]

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. [cite journal |author=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 |pmid=9881690]

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. [cite journal |author=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] [cite journal |author=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 |pmid=1714327]

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. [cite journal |author=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 |pmid=1379234] These three genes produce six different mRNA transcripts ; two from CD64A, three from CD64B, and one from CD64C; by alternate splicing of the genes. [cite journal |author=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 |pmid=9881690]

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