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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

The Apc5 subunit of the anaphase-promoting complex/cyclosome interacts with poly(A) binding protein and represses

Nadejda Koloteva-Levine1, Dalia Pinchasi, Idan Pereman

  • 1Department of Cell Research & Immunology, George S. Wise Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel.

Molecular and Cellular Biology
|April 15, 2004
PubMed

Insights

Apc5, an anaphase-promoting complex/cyclosome (APC/C) subunit, unexpectedly binds mRNA IRES elements via PABP. Apc5 regulates IRES translation and is degraded during differentiation, suggesting a novel role beyond the APC/C complex.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • The anaphase-promoting complex/cyclosome (APC/C) is a crucial E3 ubiquitin ligase regulating cell cycle progression through proteolysis.
  • Internal ribosome entry site (IRES) elements facilitate cap-independent translation initiation, particularly under stress conditions.

Purpose of the Study:

  • To identify proteins interacting with the platelet-derived growth factor 2 mRNA IRES.
  • To investigate the novel function of APC/C subunit Apc5 in translation regulation.

Main Methods:

  • Yeast three-hybrid screening to identify IRES-interacting proteins.
  • Co-immunoprecipitation and Western blotting to confirm protein interactions.
  • Analysis of IRES-mediated translation efficiency and protein degradation during megakaryocytic differentiation.

Main Results:

  • Apc5 was identified as an IRES-interacting protein, binding PABP which directly interacts with the IRES.
  • Apc5 overexpression inhibited PABP-enhanced IRES-mediated translation.
  • Apc5, unlike Apc3, is degraded during megakaryocytic differentiation, correlating with IRES activation.
  • Apc5 expression in differentiated cells repressed IRES activation.

Conclusions:

  • Apc5 possesses a novel function in regulating IRES-mediated translation, independent of its role in the APC/C complex.
  • The interaction of Apc5 with the IRES-PABP complex highlights a new layer of translational control.
  • Apc5 degradation during differentiation is linked to the activation of specific IRES elements.

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