Biology:CD64

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Short description: Integral membrane glycoprotein
Fc fragment of IgG, high affinity Ia, receptor (CD64)
Identifiers
SymbolFCGR1A
NCBI gene2209
HGNC3613
OMIM146760
RefSeqNM_000566
UniProtP12314
Other data
LocusChr. 1 q21.2-21.3
Fc fragment of IgG, high affinity Ib, receptor (CD64)
Identifiers
SymbolFCGR1B
NCBI gene2210
HGNC3614
OMIM601502
RefSeqNM_001004340
UniProtQ92637
Other data
LocusChr. 1 p11.2
Fc fragment of IgG, high affinity Ic, receptor (CD64)
Identifiers
SymbolFCGR1C
NCBI gene2211
HGNC3615
OMIM601503
RefSeqXM_001133198
Other data
LocusChr. 1 q21.1

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.[1] 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.[2]

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.[3]

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.[4][5]

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.[6] These three genes produce six different mRNA transcripts; two from CD64A, three from CD64B, and one from CD64C; by alternate splicing.[3]

References

  1. "The second and third extracellular domains of FcgammaRI (CD64) confer the unique high affinity binding of IgG2a". Mol Immunol 35 (14–15): 989–96. 1998. doi:10.1016/S0161-5890(98)00069-8. PMID 9881694. 
  2. "Fcgamma receptors: old friends and new family members". Immunity 24 (1): 19–28. 2006. doi:10.1016/j.immuni.2005.11.010. PMID 16413920. 
  3. 3.0 3.1 "Molecular characterization of six variant Fcgamma receptor class I (CD64) transcripts". Mol Immunol 35 (14–15): 943–54. 1998. doi:10.1016/s0161-5890(98)00079-0. PMID 9881690. 
  4. "Immune interferon induces the receptor for monomeric IgG1 on human monocytic and myeloid cells". J Exp Med 158 (4): 1092–113. 1983. doi:10.1084/jem.158.4.1092. PMID 6225822. 
  5. "Neutrophils express the high affinity receptor for IgG (Fc gamma RI, CD64) after in vivo application of recombinant human granulocyte colony-stimulating factor". Blood 78 (4): 885–9. 1991. doi:10.1182/blood.V78.4.885.885. PMID 1714327. 
  6. "Three genes for the human high affinity Fc receptor for IgG (Fc gamma RI) encode four distinct transcription products". J Biol Chem 267 (22): 15692–700. 1992. doi:10.1016/S0021-9258(19)49591-4. PMID 1379234. 

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