Tyrosine kinase but not phospholipid/Ca2+ signaling pathway is involved in interferon-γ stimulation of la expression in macrophages

Rabindranath Chakrabarti, Kent L Erickson

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The specific signal transduction pathway(s) involved in the induction of the expression of the MHC class II molecule, la, on macrophages by interferon-γ (IFN-γ) is unclear. In this paper, we assessed the role of several signal transduction pathways including calcium mobilization, phospholipase C, protein kinase C and cyclic nucleotide-dependent protein kinase, and thetyrosine kinase pathways. IFN-γ was unable to mobilize intracellular calcium, unlike platelet-activating factor, which stimulated a threefold increase in cytosolic Ca2+ concentration in macrophages. Inhibition of the phospholipase C pathway by U73122 or ET-180CH3 and of phosphatidic acid phosphohydrolase by propranolol did not suppress IFN-γ-induced la expression. In addition, inhibition of protein kinase C by calphostin C or cyclic nucleotide-dependent protein kinase by HA1004 did not suppress la expression. However, IFN-γ-induced la expression was significantly suppressed when the tyrosine kinase pathway was inhibited with herbimycin A and genestein. In addition, those two inhibitors suppressed tyrosine phosphorylation of several proteins in macrophages that may or may not be involved in the induction of la expression. Thus, IFN-γ used only the tyrosine kinase signaling pathway, but not the phospholipid/Ca2+ signaling pathways, to induce la expression in macrophages.

Original languageEnglish (US)
Pages (from-to)235-245
Number of pages11
JournalJournal of Cellular Biochemistry
Issue number2
StatePublished - 1996

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology


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