Caspase-2 promotes cytoskeleton protein degradation during apoptotic cell death

Cell Death Dis. 2013 Dec 5;4(12):e940. doi: 10.1038/cddis.2013.463.

Abstract

The caspase family of proteases cleaves large number of proteins resulting in major morphological and biochemical changes during apoptosis. Yet, only a few of these proteins have been reported to selectively cleaved by caspase-2. Numerous observations link caspase-2 to the disruption of the cytoskeleton, although it remains elusive whether any of the cytoskeleton proteins serve as bona fide substrates for caspase-2. Here, we undertook an unbiased proteomic approach to address this question. By differential proteome analysis using two-dimensional gel electrophoresis, we identified four cytoskeleton proteins that were degraded upon treatment with active recombinant caspase-2 in vitro. These proteins were degraded in a caspase-2-dependent manner during apoptosis induced by DNA damage, cytoskeleton disruption or endoplasmic reticulum stress. Hence, degradation of these cytoskeleton proteins was blunted by siRNA targeting of caspase-2 and when caspase-2 activity was pharmacologically inhibited. However, none of these proteins was cleaved directly by caspase-2. Instead, we provide evidence that in cells exposed to apoptotic stimuli, caspase-2 probed these proteins for proteasomal degradation. Taken together, our results depict a new role for caspase-2 in the regulation of the level of cytoskeleton proteins during apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics
  • Apoptosis / physiology
  • Caspase 2 / genetics
  • Caspase 2 / metabolism*
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism*
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism*
  • Electrophoresis, Gel, Two-Dimensional
  • Endoplasmic Reticulum Stress
  • HCT116 Cells
  • Humans
  • Proteomics / methods*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tandem Mass Spectrometry

Substances

  • Cytoskeletal Proteins
  • CASP2 protein, human
  • Caspase 2
  • Cysteine Endopeptidases