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
- ^ Hulett M, Hogarth P (1998). "The second and third extracellular domains of FcgammaRI (CD64) confer the unique high affinity binding of IgG2a". Mol Immunol. 35 (14–15): 989–96. doi:10.1016/S0161-5890(98)00069-8. PMID 9881694.
- ^ Nimmerjahn F, Ravetch J (2006). "Fcgamma receptors: old friends and new family members". Immunity. 24 (1): 19–28. doi:10.1016/j.immuni.2005.11.010. PMID 16413920.
- ^ a b Ernst L, Duchemin A, Miller K, Anderson C (1998). "Molecular characterization of six variant Fcgamma receptor class I (CD64) transcripts". Mol Immunol. 35 (14–15): 943–54. doi:10.1016/s0161-5890(98)00079-0. PMID 9881690.
- ^ Perussia B, Dayton E, Lazarus R, Fanning V, Trinchieri G (1983). "Immune interferon induces the receptor for monomeric IgG1 on human monocytic and myeloid cells". J Exp Med. 158 (4): 1092–113. doi:10.1084/jem.158.4.1092. PMC 2187379. PMID 6225822.
- ^ Repp R, Valerius T, Sendler A, Gramatzki M, Iro H, Kalden J, Platzer E (1991). "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. doi:10.1182/blood.V78.4.885.885. PMID 1714327.
- ^ Ernst L, van de Winkel J, Chiu I, Anderson C (1992). "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. doi:10.1016/S0021-9258(19)49591-4. PMID 1379234.
External links
- CD64+Antigens at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
This page was last edited on 17 July 2023, at 21:39