CD64 (Cluster ofDifferentiation64) is a type ofintegral membraneglycoprotein known as anFc receptor that bindsmonomeric IgG-typeantibodies with highaffinity.[1] It is more commonly known as Fc-gamma receptor 1 (FcγRI). After bindingIgG, CD64 interacts with an accessory chain known as the common γ chain (γ chain), which possesses anITAM motif that is necessary for triggering cellular activation.[2]
Structurally CD64 is composed of asignal peptide that allows its transport to the surface of a cell, threeextracellularimmunoglobulin domains of the C2-type that it uses to bind antibody, ahydrophobic transmembrane domain, and a short cytoplasmic tail.[3]
There are three distinct (but highly similar)genes in humans for CD64 called FcγRIA (CD64A), FcγRIB (CD64B), and FcγRIC (CD64C) that are located onchromosome 1.[6] These three genes produce six differentmRNA transcripts; two from CD64A, three from CD64B, and one from CD64C; by alternate splicing.[3]
^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.PMID9881694.
^abErnst 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.PMID9881690.
