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High-throughput Quantitative Real-time RT-PCR Assay for Determining Expression Profiles of Types I and III Interferon Subtypes
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Interferon-alpha selectively activates the beta isoform of protein kinase C through phosphatidylcholine hydrolysis

L M Pfeffer1, B Strulovici, A R Saltiel

  • 1Rockefeller University, New York, NY 10021.

Proceedings of the National Academy of Sciences of the United States of America
|September 1, 1990
PubMed

Insights

Interferon-alpha activates protein kinase C (PKC) in HeLa cells, a crucial step for its antiviral effects. This activation involves diacylglycerol production and selective PKC-beta translocation, impacting cell proliferation.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Immunology

Background:

  • The early cellular events following interferon binding to cell surface receptors are not well understood.
  • Interferon-alpha is known to modulate cellular processes, but the precise molecular mechanisms are unclear.

Purpose of the Study:

  • To investigate the early molecular events triggered by interferon-alpha in HeLa cells.
  • To determine the role of protein kinase C (PKC) activation in interferon-alpha's cellular effects.

Main Methods:

  • Measuring [3H]phorbol dibutyrate binding to assess PKC activation.
  • Analyzing the subcellular distribution of PKC isoforms (alpha, beta, epsilon) using cell fractionation.
  • Assessing the impact of PKC activation/down-regulation on interferon-alpha's effects on cell proliferation and antiviral activity.
  • Quantifying phosphatidylcholine hydrolysis and inositol phospholipid turnover.

Main Results:

  • Interferon-alpha rapidly increased [3H]phorbol dibutyrate binding, indicating PKC activation.
  • Interferon-alpha selectively translocated the PKC-beta isoform from the cytosol to the particulate fraction.
  • PKC activation mimicked interferon-alpha's inhibition of HeLa cell proliferation.
  • Down-regulation of PKC blocked interferon-alpha's induction of antiviral activity.
  • Interferon-alpha increased diacylglycerol production via phosphatidylcholine hydrolysis but did not affect inositol phospholipid turnover or intracellular calcium.

Conclusions:

  • Interferon-alpha activates protein kinase C (PKC), specifically the beta isoform, through diacylglycerol production.
  • PKC activation is a necessary mediator of interferon-alpha's effects on cell proliferation and antiviral activity.
  • These findings elucidate a key molecular pathway in cellular responses to interferon-alpha.

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