Palmitoylation of interferon-alpha (IFN-alpha) receptor subunit IFNAR1 is required for the activation of Stat1 and Stat2 by IFN-alpha.
Type I interferons (IFNs) bind IFNAR receptors and activate Jak kinases and Stat transcription factors to stimulate the transcription of genes downstream from IFN-stimulated response elements. In this study, we analyze the role of protein palmitoylation, a reversible post-translational lipid modification, in the functional properties of IFNAR. We report that pharmacological inhibition of protein palmitoylation results in severe defects of IFN receptor endocytosis and signaling. We generated mutants of the IFNAR1 subunit of the type I IFN receptor, in which each or both of the two cysteines present in the cytoplasmic domain are replaced by alanines. We show that cysteine 463 of IFNAR1, the more proximal of the two cytoplasmic cysteines, is palmitoylated. A thorough microscopic and biochemical analysis of the palmitoylation-deficient IFNAR1 mutant revealed that IFNAR1 palmitoylation is not required for receptor endocytosis, intracellular distribution, or stability at the cell surface. However, the lack of IFNAR1 palmitoylation affects selectively the activation of Stat2, which results in a lack of efficient Stat1 activation and nuclear translocation and IFN-alpha-activated gene transcription. Thus, receptor palmitoylation is a previously undescribed mechanism of regulating signaling activity by type I IFNs in the Jak/Stat pathway.
Claudinon
Julie
J
Institut Curie, Centre de Recherche, Laboratoire Trafic, Signalisation et Ciblage Intracellulaires, 75248 Paris Cedex 05, France.
Gonnord
Pauline
P
Beslard
Emilie
E
Marchetti
Marta
M
Mitchell
Keith
K
Boularan
Cédric
C
Johannes
Ludger
L
Eid
Pierre
P
Lamaze
Christophe
C
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000235:genetics; D019943:Amino Acid Substitution; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects / Q000235:genetics; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D051379:Mice; D020125:Mutation, Missense; D019308:Palmitic Acid / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects* / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D053633:Receptor, Interferon alpha-beta / Q000235:genetics / Q000378:metabolism*; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D050795:STAT2 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
D000998:Antiviral Agents; C507964:IFNAR1 protein, human; D016898:Interferon-alpha; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050795:STAT2 Transcription Factor; C494084:STAT2 protein, human; D053633:Receptor, Interferon alpha-beta; D019308:Palmitic Acid