Protein tyrosine kinase Pyk2 mediates the Jak-dependent activation of MAPK and Stat1 in IFN-gamma, but not IFN-alpha, signaling.
Two distinct types of interferon, IFN-alpha/beta and IFN-gamma, commonly exhibit antiviral activities by transmitting signals to the interior of the cell via their homologous receptors. Receptor stimulation results in the activation of distinct combinations of Janus family protein tyrosine kinases (Jak PTKs); Jak1/Tyk2 and Jak1/Jak2 for IFN-alpha/beta and IFN-gamma, respectively. Jak PTK activation by these IFNs is commonly followed by tyrosine phosphorylation of the transcription factor Stat1 at Y701, which is essential for dimerization, translocation to the nucleus and DNA-binding activity. To gain full transcriptional activity, Stat1 also requires serine phosphorylation at S727. In this paper we demonstrate that Pyk2, which belongs to another PTK family, is critical for the Jak-mediated MAPK and Stat1 activation by IFN-gamma, but not IFN-alpha. Pyk2 is selectively associated with Jak2 and activated by IFN-gamma. Overexpression of PKM, a dominant interfering form of Pyk2, in NIH 3T3 cells results in a strong inhibition of the IFN-gamma-induced activation of Erk2, serine phosphorylation of Stat1 and Stat1-dependent gene transcription. Finally, the antiviral action of IFN-gamma, but not IFN-alpha, is severely impaired by PKM overexpression. Thus, the two types of IFN may utilize distinct Jak-mediated Erk2, and possibly other MAPK activation pathways for their antiviral action.
Takaoka
A
A
Department of Immunology, Graduate School of Medicine, and Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Tanaka
N
N
Mitani
Y
Y
Miyazaki
T
T
Fujii
H
H
Sato
M
M
Kovarik
P
P
Decker
T
T
Schlessinger
J
J
Taniguchi
T
T
D016475:3T3 Cells; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D051418:Focal Adhesion Kinase 2; D007113:Immunity, Innate; D016898:Interferon-alpha / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D053614:Janus Kinase 2; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D050794:STAT1 Transcription Factor; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D014780:Viruses / Q000472:pathogenicity
D000998:Antiviral Agents; D004268:DNA-Binding Proteins; D016898:Interferon-alpha; D011518:Proto-Oncogene Proteins; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D014443:Tyrosine; D012694:Serine; D007371:Interferon-gamma; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; C496053:Ptk2b protein, mouse; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1