MyD88 couples the activation of the Toll-like receptors and interleukin-1 receptor superfamily with intracellular signaling pathways. Upon ligand binding, activated receptors recruit MyD88 via its Toll-interleukin-1 receptor domain. MyD88 then allows the recruitment of the interleukin-1 receptor-associated kinases (IRAKs). We performed a site-directed mutagenesis of MyD88 residues, conserved in death domains of the homologous FADD and Pelle proteins, and analyzed the effect of the mutations on MyD88 signaling. Our studies revealed that mutation of residues 52 (MyD88(E52A)) and 58 (MyD88(Y58A)) impaired recruitment of both IRAK1 and IRAK4, whereas mutation of residue 95 (MyD88(K95A)) only affected IRAK4 recruitment. Since all MyD88 mutants were defective in signaling, recruitment of both IRAKs appeared necessary for activation of the pathway. Moreover, overexpression of a green fluorescent protein (GFP)-tagged mini-MyD88 protein (GFP-MyD88-(27-72)), comprising the Glu(52) and Tyr(58) residues, interfered with recruitment of both IRAK1 and IRAK4 by MyD88 and suppressed NF-kappaB activation by the interleukin-1 receptor but not by the MyD88-independent TLR3. GFP-MyD88-(27-72) exerted its effect by titrating IRAK1 and suppressing IRAK1-dependent NF-kappaB activation. These experiments identify novel residues of MyD88 that are crucially involved in the recruitment of IRAK1 and IRAK4 and in downstream propagation of MyD88 signaling.

Loiarro, M., Gallo, G., Fantò, N., De Santis, R., Carminati, P., Ruggiero, V., et al. (2009). Identification of critical residues of the MyD88 death domain involved in the recruitment of downstream kinases. JOURNAL OF BIOLOGICAL CHEMISTRY, 284(41), 28093-28103 [10.1074/jbc.M109.004465].

Identification of critical residues of the MyD88 death domain involved in the recruitment of downstream kinases

SETTE, CLAUDIO
2009-10-09

Abstract

MyD88 couples the activation of the Toll-like receptors and interleukin-1 receptor superfamily with intracellular signaling pathways. Upon ligand binding, activated receptors recruit MyD88 via its Toll-interleukin-1 receptor domain. MyD88 then allows the recruitment of the interleukin-1 receptor-associated kinases (IRAKs). We performed a site-directed mutagenesis of MyD88 residues, conserved in death domains of the homologous FADD and Pelle proteins, and analyzed the effect of the mutations on MyD88 signaling. Our studies revealed that mutation of residues 52 (MyD88(E52A)) and 58 (MyD88(Y58A)) impaired recruitment of both IRAK1 and IRAK4, whereas mutation of residue 95 (MyD88(K95A)) only affected IRAK4 recruitment. Since all MyD88 mutants were defective in signaling, recruitment of both IRAKs appeared necessary for activation of the pathway. Moreover, overexpression of a green fluorescent protein (GFP)-tagged mini-MyD88 protein (GFP-MyD88-(27-72)), comprising the Glu(52) and Tyr(58) residues, interfered with recruitment of both IRAK1 and IRAK4 by MyD88 and suppressed NF-kappaB activation by the interleukin-1 receptor but not by the MyD88-independent TLR3. GFP-MyD88-(27-72) exerted its effect by titrating IRAK1 and suppressing IRAK1-dependent NF-kappaB activation. These experiments identify novel residues of MyD88 that are crucially involved in the recruitment of IRAK1 and IRAK4 and in downstream propagation of MyD88 signaling.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/16
English
Con Impact Factor ISI
Toll-Like Receptor 3; Protein Structure, Tertiary; Hela Cells; Animals; Proto-Oncogene Proteins c-myc; Receptors, Interleukin-1; Humans; Myeloid Differentiation Factor 88; Interleukin-1 Receptor-Associated Kinases; Protein Isoforms; Signal Transduction; Recombinant Fusion Proteins; Mutagenesis, Site-Directed; Molecular Sequence Data; Sequence Alignment; Amino Acid Sequence; Genes, Reporter; NF-kappa B
Loiarro, M., Gallo, G., Fantò, N., De Santis, R., Carminati, P., Ruggiero, V., et al. (2009). Identification of critical residues of the MyD88 death domain involved in the recruitment of downstream kinases. JOURNAL OF BIOLOGICAL CHEMISTRY, 284(41), 28093-28103 [10.1074/jbc.M109.004465].
Loiarro, M; Gallo, G; Fantò, N; De Santis, R; Carminati, P; Ruggiero, V; Sette, C
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/30494
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