Differential role of Janus family kinases (JAKs) in interferon-gamma-induced lung epithelial ICAM-1 expression: involving protein interactions between JAKs, phospholipase Cgamma, c-Src, and STAT1

Mol Pharmacol. 2004 Mar;65(3):589-98. doi: 10.1124/mol.65.3.589.


The signaling pathway for IFN-gamma-mediated induction of ICAM-1 expression was further studied in human NCI-H292 epithelial cells. The Tyr701 phosphorylation of signal transducer and activator of transcription 1 (STAT1) induced by interferon-gamma (IFN-gamma) and 12-O-tetradecanoylphorbol 13-acetate (TPA) was inhibited by the protein kinase C (PKC) inhibitor staurosporine, the tyrosine kinase inhibitor herbimycin, or the Src kinase inhibitor PP2. An association between c-Src and STAT1 was increased by IFN-gamma and TPA, indicating the direct phosphorylation of STAT1 by PKC-dependent c-Src activation. Tyrosine phosphorylation of Janus kinases (JAK) 1/2 was induced by IFN-gamma but not by TPA. In addition, ICAM-1 promoter activity induced by IFN-gamma, but not that induced by TPA, was inhibited by the dominant-negative JAK1 and JAK2 mutants. IFN-gamma-induced tyrosine phosphorylation of phospholipase C (PLC)-gamma was inhibited by AG 490 (a JAK inhibitor), and the association between JAK1/2 and PLC-gamma was increased after IFN-gamma treatment, indicating the activation of PLC-gamma via JAK1/2 phosphorylation. ICAM-1 promoter activities induced by the overexpression of wild-type JAK1- and PLC-gamma2 were blocked by the PLCgamma2 mutant or the dominant-negative PKCalpha (Lys-->Arg), c-Src (Lys-->Met), or STAT1 (Y701M) mutants, but not by dominant-negative STAT3 (DN) mutants. These results confirmed that IFN-gamma activated PLC-gamma via JAK1/2 phosphorylation to induce PKC, c-Src, STAT1 activation, and ICAM-1 expression. The association between JAK1/2 and STAT1 was increased by IFN-gamma but not by TPA. It was inhibited by AG 490 but not by U73122, indicating the possible involvement of the JAK1/2-STAT1 pathway. All the results show that IFN-gamma induces ICAM-1 expression by two different pathways in NCI-H292 epithelial cells. One is the JAK1/2-dependent PLC-gamma pathway inducing the activations of PKCalpha, c-Src, and STAT1, and the other is the direct activation of STAT1 by JAK1/2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA-Binding Proteins / metabolism*
  • Epithelial Cells / drug effects*
  • Epithelial Cells / metabolism
  • Gene Expression
  • Humans
  • Intercellular Adhesion Molecule-1 / genetics
  • Intercellular Adhesion Molecule-1 / metabolism*
  • Interferon-gamma / pharmacology
  • Janus Kinase 1
  • Janus Kinase 2
  • Lung / cytology
  • Phospholipase C gamma
  • Phosphorylation
  • Promoter Regions, Genetic / drug effects
  • Protein-Tyrosine Kinases / metabolism
  • Protein-Tyrosine Kinases / physiology*
  • Proto-Oncogene Proteins*
  • RNA, Messenger / drug effects
  • RNA, Messenger / metabolism
  • STAT1 Transcription Factor
  • Tetradecanoylphorbol Acetate / pharmacology
  • Trans-Activators / metabolism*
  • Type C Phospholipases / metabolism*
  • Tyrosine / metabolism
  • src-Family Kinases / metabolism*


  • DNA-Binding Proteins
  • Proto-Oncogene Proteins
  • RNA, Messenger
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • Trans-Activators
  • Intercellular Adhesion Molecule-1
  • Tyrosine
  • Interferon-gamma
  • Protein-Tyrosine Kinases
  • JAK1 protein, human
  • JAK2 protein, human
  • Janus Kinase 1
  • Janus Kinase 2
  • src-Family Kinases
  • Type C Phospholipases
  • Phospholipase C gamma
  • Tetradecanoylphorbol Acetate