Abstract
The Fanconi anemia (FA) group C protein, FANCC, interacts with STAT1 following stimulation with IFN-gamma and is required for proper docking of STAT1 at the IFN-gamma receptor alpha-chain (IFN-gammaRalpha, IFN-gammaR1). Consequently, loss of a functional FANCC results in decreased activation of STAT1 following IFN-gamma stimulation. Because type I IFN receptors influence the function of type II receptors, and vice versa, we conducted experiments designed to determine whether type I IFN-induced activation of other STAT proteins is compromised in FA-C cells and found that activation of STAT 1, 3, and 5 is diminished in type I IFN-stimulated cells bearing Fancc-inactivating mutations. We also determined that the reduced activation of STATs was accompanied by significant reduction of type I IFN-induced tyrosine kinase 2 and Jak1 phosphorylation. Because tyrosine kinase 2 plays a role in differentiation of Th cells, we quantified cytokine secretion from CD4+ cells and in vitro generated CD4+ Th cell subsets from splenocytes of Fancc null mice to that of heterozygous mice and discovered reduced CD4+ IFN-gamma secretion in the Fancc-/- mouse, indicating impaired Th1 differentiation. We suggest that Fancc mutations result in a subtle immunological defect owing to the failure of FANCC to normally support Jak/STAT signaling.
Copyright 2004 The American Association of Immunologists, Inc.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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B-Lymphocyte Subsets / enzymology
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B-Lymphocyte Subsets / immunology
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B-Lymphocyte Subsets / metabolism
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CD4-Positive T-Lymphocytes / immunology
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CD4-Positive T-Lymphocytes / metabolism
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CD4-Positive T-Lymphocytes / pathology*
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Cell Cycle Proteins*
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Cell Differentiation / genetics
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Cell Differentiation / immunology
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Cell Line, Transformed
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / metabolism
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Fanconi Anemia / enzymology*
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Fanconi Anemia / genetics
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Fanconi Anemia / immunology*
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Fanconi Anemia Complementation Group C Protein
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Fanconi Anemia Complementation Group Proteins
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Gene Silencing / immunology
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Interferon Type I / physiology*
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Interferon-gamma / antagonists & inhibitors
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Interferon-gamma / biosynthesis
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Interleukin-6 / physiology
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Janus Kinase 1
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Leukemia Inhibitory Factor
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Mice
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Mice, Knockout
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Nuclear Proteins*
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Phosphorylation
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Protein Binding / immunology
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Protein-Tyrosine Kinases / antagonists & inhibitors
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Protein-Tyrosine Kinases / metabolism
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Protein-Tyrosine Kinases / physiology*
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Proteins / genetics*
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Proteins / physiology
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Receptor, Interferon alpha-beta
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Receptors, Interferon / biosynthesis
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Receptors, Interferon / metabolism
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STAT1 Transcription Factor
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STAT2 Transcription Factor
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Signal Transduction / immunology*
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Spleen / immunology
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Spleen / pathology
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TYK2 Kinase
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Th1 Cells / immunology
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Th1 Cells / metabolism
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Th1 Cells / pathology
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Trans-Activators / antagonists & inhibitors
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Trans-Activators / metabolism
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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Fancc protein, mouse
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Fanconi Anemia Complementation Group C Protein
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Fanconi Anemia Complementation Group Proteins
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Interferon Type I
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Interleukin-6
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Leukemia Inhibitory Factor
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Lif protein, mouse
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Nuclear Proteins
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Proteins
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Receptors, Interferon
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STAT1 Transcription Factor
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STAT2 Transcription Factor
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Stat1 protein, mouse
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Trans-Activators
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Receptor, Interferon alpha-beta
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Interferon-gamma
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Protein-Tyrosine Kinases
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Jak1 protein, mouse
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Janus Kinase 1
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TYK2 Kinase
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Tyk2 protein, mouse