p38 MAP kinase is required for STAT1 serine phosphorylation and transcriptional activation induced by interferons.
Activation of cytosolic phospholipase A(2 )(cPLA(2)) is a prerequisite for the formation of the transcription factor complex interferon-stimulated gene factor 3 (ISGF3) in response to interferon-alpha (IFN-alpha). Here we show that p38 mitogen-activated protein kinase (MAPK), an activator of cPLA(2), is essential for both IFN-alpha and IFN-gamma signalling. SB203580, a specific inhibitor of p38, was found to inhibit ISGF3 formation but had no apparent effects on signal transducer and activator of transcription (STAT)1 homodimer formation. Regardless of this, the antiviral activities of both IFN-alpha and IFN-gamma were attenuated by SB203580. Treatment with either IFN led to rapid and transient activation of p38. Both IFNs induced STAT1 Ser727 phosphorylation, which was inhibited by SB203580 but not by an extracellular signal related kinase (ERK)1/2 inhibitor (PD98059). In an inducible 3T3-L1 clone, expression of dominant-negative p38 led to defective STAT1 serine phosphorylation and diminished IFN-gamma-mediated protection against viral killing. Reporter activity mediated by ISGF3 or STAT1 homodimer was diminished by SB203580 and enhanced by a constitutively active mutant of MKK6, the upstream activator of p38. Therefore, p38 plays a key role in the serine phosphorylation of STAT1 and transcriptional changes induced by both IFNs.
Goh
K C
KC
Department of Cancer Biology/NB40, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Haque
S J
SJ
Williams
B R
BR
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007370:Interferon Type I / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D048669:MAP Kinase Kinase 6; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009154:Mutation; D010741:Phospholipases A / Q000378:metabolism; D010766:Phosphorylation; D020836:Protein Structure, Quaternary; D011725:Pyridines / Q000494:pharmacology; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor; D012694:Serine / Q000378:metabolism; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases
D017931:DNA Primers; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D007370:Interferon Type I; D011725:Pyridines; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D012694:Serine; D007371:Interferon-gamma; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048669:MAP Kinase Kinase 6; C482566:MAP2K6 protein, human; C482567:Map2k6 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases; D010741:Phospholipases A; C093642:SB 203580