Stability of IL-2 mRNA in T lymphocytes is controlled by a protein kinase C-regulated mechanism

Int Immunol. 1990;2(11):1073-9. doi: 10.1093/intimm/2.11.1073.

Abstract

The rate of the degradation of interleukin 2 (IL-2) mRNA produced in stimulated human tonsillar lymphocytes was found to be significantly decreased in cells continuously stimulated with a calcium ionophore, A23187, and a phorbol ester, phorbol 12, 13-dibutylate (PDB) as compared with that in unstimulated cells. When the lymphocytes were stimulated with A23187 and PDB, IL-2 mRNA reached a maximum level at 8 h and gradually decreased to almost the base line by 27 h. IL-2 mRNA produced was rapidly degraded when the stimulants were washed out at 12 h and the cells further cultured in the presence of actinomycin D, which stops mRNA synthesis. However, the stability of IL-2 mRNA was increased by the addition of PDB or A23187. A maximal effect was observed when both were added. The effect of PDB was dose-dependent and inhibited by the inhibitors of protein kinase C (PKC), staurosporine, and K252a, suggesting the involvement of PKC in the control of IL-2 mRNA stability. The involvement of protein phosphorylation in the regulating mechanism of IL-2 mRNA stability was supported by the fact that the addition of okadaic acid, which inhibits serine/threonine protein phosphatases, resulted in an increase in the stability of IL-2 mRNA. Further study demonstrated that the rate of degradation of 32P-labeled IL-2 mRNA, which was prepared by cell-free transcription of IL-2 cDNA, in the polysomal fraction obtained from PDB-stimulated lymphocytes was decreased compared with that obtained from unstimulated lymphocytes. These results indicate the presence of a mechanism controlling the stability of IL-2 mRNA that is regulated by PKC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcimycin / pharmacology
  • Cell-Free System
  • Cells, Cultured
  • Humans
  • Interleukin-2 / metabolism*
  • Kinetics
  • Phorbol 12,13-Dibutyrate / pharmacology
  • Phosphoprotein Phosphatases / antagonists & inhibitors
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • RNA, Messenger / metabolism*
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism

Substances

  • Interleukin-2
  • RNA, Messenger
  • Phorbol 12,13-Dibutyrate
  • Calcimycin
  • Protein Kinase C
  • Phosphoprotein Phosphatases