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Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation
08:47

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation

Published on: March 5, 2018

Far upstream element-binding protein-1, a novel caspase substrate, acts as a cross-talker between apoptosis and the

M Jang1, B C Park, S Kang

  • 1Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea.

Oncogene
|February 17, 2009
PubMed

Insights

Far upstream element-binding protein-1 (FBP-1) is cleaved by caspases during apoptosis, reducing its nuclear presence. This cleavage downregulates oncogenic c-Myc, suggesting a mechanism to switch off cancer-promoting activity.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Far upstream element-binding protein-1 (FBP-1) regulates c-myc mRNA levels.
  • FBP-1 was previously identified as a potential substrate for caspase-7.

Purpose of the Study:

  • To investigate the cleavage of FBP-1 by executor caspases during apoptosis.
  • To determine the functional consequences of FBP-1 cleavage on c-Myc regulation and apoptosis.

Main Methods:

  • In vitro caspase cleavage assays.
  • Apoptosis induction in cells.
  • Analysis of FBP-1 localization and c-Myc expression.
  • Use of a non-cleavable FBP-1 mutant (D74A).

Main Results:

  • FBP-1 is cleaved by executor caspases at a specific site (DQPD74) within its nuclear localization signal during apoptosis.
  • Caspase-mediated cleavage of FBP-1 results in its decreased nuclear localization.
  • This leads to the downregulation of c-Myc and its target proteins, and cells with non-cleavable FBP-1 are protected from apoptosis.

Conclusions:

  • Caspase-mediated cleavage of FBP-1 is a key event during apoptosis.
  • This cleavage mechanism effectively 'switches off' the oncogenic potential of c-Myc by reducing its regulatory protein's nuclear presence.
  • FBP-1 cleavage represents a novel regulatory pathway linking apoptosis induction to the suppression of oncogenic factors.

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