IL-4 receptor signal transduction in human monocytes is associated with protein kinase C translocation

J Immunol. 1992 Aug 15;149(4):1258-64.

Abstract

IL-4 regulates B cell differentiation and monocyte functions. Protein kinases, such as kinase C (PKC), transduce receptor signals. The involvement of PKC in IL-4R signaling was investigated in human monocytes. Treatment with IL-4 (10 ng/ml) for 10 min resulted in a significant redistribution of the PKC activity from cytosol to nuclear fraction. Total PKC activity localized in the nuclear fraction of IL-4-treated and control monocytes was, respectively, 68 and 19%. In contrast, similar PKC activity was found in membrane fraction of IL-4-treated and control cells. The kinetics of IL-4-mediated redistribution of PKC activity to the nuclear fraction were rapid. Within 30 s of IL-4 exposure, 29% of the total PKC activity localized in the nuclear fraction as compared to 15% in control monocytes and increased to 69% at 10 min. The PKC activity in the nuclear fraction appears to be a sequestered form. Extraction with Triton X-100 and additional sonication were required for functional assay of PKC activity. Additional support for PKC involvement in IL-4R signaling is provided by the dose-dependent effect of IL-4 on PKC activity and the abrogation of this effect after heat denature and immunoabsorption of IL-4. Furthermore, electron microscope examination and subcellular marker enzyme assays excluded significant contamination of the nuclear fraction by plasma membranes or subcellular organelles and IL-4 altering membrane disruption. The data presented indicate that IL-4R signaling in human monocytes involves PKC translocation to a nuclear fraction.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Compartmentation
  • Cell Membrane / enzymology
  • Cell Nucleus / enzymology
  • Cytosol / enzymology
  • Dose-Response Relationship, Drug
  • Enzyme Activation
  • Humans
  • Interleukin-4 / pharmacology*
  • Monocytes / physiology*
  • Protein Kinase C / physiology*
  • Receptors, Interleukin-4
  • Receptors, Mitogen / physiology*
  • Signal Transduction

Substances

  • Receptors, Interleukin-4
  • Receptors, Mitogen
  • Interleukin-4
  • Protein Kinase C