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 of the genes.[3] [edit] 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. 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. 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. 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. PMID 1379234.
[edit] External links | Proteins: clusters of differentiation (see also list of human clusters of differentiation) | | | 1-50 | CD1 ( a-c, 1A, 1D, 1E) · CD2 · CD3 ( γ, δ, ε) · CD4 · CD5 · CD6 · CD7 · CD8 ( a) · CD9 · CD10 · CD11 ( a, b, c) · CD13 · CD14 · CD15 · CD16 ( A, B) · CD18 · CD19 · CD20 · CD21 · CD22 · CD23 · CD24 · CD25 · CD26 · CD27 · CD28 · CD29 · CD30 · CD31 · CD32 ( A, B) · CD33 · CD34 · CD35 · CD36 · CD37 · CD38 · CD39 · CD40 · CD41 · CD42 ( a, b, c, d) · CD43 · CD44 · CD45 · CD46 · CD47 · CD48 · CD49 ( a, b, c, d, e, f) · CD50 | | | 51-100 | CD51 · CD52 · CD53 · CD54 · CD55 · CD56 · CD57 · CD58 · CD59 · CD61 · CD62 ( E, L, P) · CD63 · CD64 ( A, B, C) · CD66 ( a, b, c, d, e, f) · CD68 · CD69 · CD70 · CD71 · CD72 · CD73 · CD74 · CD78 · CD79 ( a, b) · CD80 · CD81 · CD82 · CD83 · CD84 · CD85 ( a, d, e, h, j, k) · CD86 · CD87 · CD88 · CD89 · CD90 · CD91- CD92 · CD93 · CD94 · CD95 · CD97 · CD98 · CD99 · CD100 | | | 101-150 | | | | 151-200 | CD151 · CD152 · CD153 · CD154 · CD155 · CD156 ( a, b, c) · CD157 · CD158 ( a, d, e, i, k) · CD159 ( a, c) · CD160 · CD161 · CD162 · CD163 · CD164 · CD166 · CD167 ( a, b) · CD168 · CD169 · CD170 · CD171 · CD172 ( a, b, g) · CD174 · CD177 · CD178 · CD179 ( a, b) · CD181 · CD182 · CD183 · CD184 · CD185 · CD186 · CD191 · CD192 · CD193 · CD194 · CD195 · CD196 · CD197 · CDw198 · CDw199 · CD200 | | | 201-250 | | | | 251-300 | | | | 301-350 | | | | Transmembrane receptors: immune receptors | | | Cytokine receptor | | | Interleukins (2, 3, 4, 5, 6, 7, 9, 11, 12, 13, 15, 21, 23, 27) CSF receptors (EPO, GM-CSF, G-CSF) GH · prolactin · Oncostatin M · Leukemia inhibitory factor common subunits ( Common gamma chain, common beta chain, gp130) | | | | | | | | | | | | | | | | | | | Other | | | | | Other endogenous | | | | Exogenous | | |
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