CD64 (Cluster of Differentiation 64) is a type of
integral membraneglycoprotein 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
extracellularimmunoglobulin domains of the C2-type that it uses to bind antibody, a
hydrophobic 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 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.
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.