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. 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.
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. These three genes produce six different mRNA transcripts ; two from CD64A, three from CD64B, and one from CD64C; by alternate splicing of the genes.
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