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Assessment of Selective mRNA Translation in Mammalian Cells by Polysome Profiling
10:00

Assessment of Selective mRNA Translation in Mammalian Cells by Polysome Profiling

Published on: October 28, 2014

Interaction of anti-proliferative protein Tob with poly(A)-binding protein and inducible poly(A)-binding protein:

Kentaro Okochi1, Toru Suzuki, Jun-ichiro Inoue

  • 1Division of Oncology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.

Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|January 29, 2005
PubMed

Insights

Tob protein suppresses cell growth and interleukin-2 (IL-2) production by inhibiting translation of IL-2 mRNA. This occurs through Tob

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Signaling

Background:

  • Tob is an anti-proliferative protein implicated in cell growth suppression.
  • Tob mRNA is highly expressed in anergic T cells, where it suppresses interleukin-2 (IL-2) transcription via Smad interaction.

Purpose of the Study:

  • To investigate the mechanism by which Tob influences IL-2 production in T cells.
  • To identify proteins interacting with Tob and elucidate their role in translational regulation.

Main Methods:

  • Screening of an expression cDNA library using a GST-Tob probe.
  • Co-immunoprecipitation and GST-pull down assays to determine protein interactions.
  • In vitro translation assays using IL-2 mRNA and poly(A) sequences.
  • Over-expression studies in NIH3T3 cells and analysis of IL-2 production.
  • Co-immunoprecipitation in human T cells following anergic stimulation.

Main Results:

  • Identified poly(A)-binding protein (PABP) and inducible PABP (iPABP) interacting with Tob.
  • Tob associates with the carboxyl-terminal region of iPABP.
  • iPABP enhances IL-2 mRNA translation in vitro, dependent on 3'UTR and poly(A) sequences.
  • Tob abrogates iPABP-mediated enhancement of IL-2 translation.
  • Tob over-expression suppresses IL-2 production in cells expressing iPABP.
  • Tob and iPABP co-immunoprecipitate in human T cells upon anergic stimulation.

Conclusions:

  • Tob interacts with iPABP, a protein involved in enhancing IL-2 mRNA translation.
  • Tob suppresses IL-2 production by inhibiting translation of IL-2 mRNA through its interaction with iPABP.
  • These findings reveal a novel mechanism for translational control of IL-2 in anergic T cells.

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