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Mitochondrial localization of Reaper to promote inhibitors of apoptosis protein degradation conferred by GH3 domain-lipid interactions.

Publication ,  Journal Article
Freel, CD; Richardson, DA; Thomenius, MJ; Gan, EC; Horn, SR; Olson, MR; Kornbluth, S
Published in: J Biol Chem
January 4, 2008

Morphological hallmarks of apoptosis result from activation of the caspase family of cysteine proteases, which are opposed by a pro-survival family of inhibitors of apoptosis proteins (IAPs). In Drosophila, disruption of IAP function by Reaper, HID, and Grim (RHG) proteins is sufficient to induce cell death. RHG proteins have been reported to localize to mitochondria, which, in the case of both Reaper and Grim proteins, is mediated by an amphipathic helical domain known as the GH3. Through direct binding, Reaper can bring the Drosophila IAP (DIAP1) to mitochondria, concomitantly promoting IAP auto-ubiquitination and destruction. Whether this localization is sufficient to induce DIAP1 auto-ubiquitination has not been reported. In this study we characterize the interaction between Reaper and the mitochondria using both Xenopus and Drosophila systems. We find that Reaper concentrates on the outer surface of mitochondria in a nonperipheral manner largely mediated by GH3-lipid interactions. Importantly, we show that mitochondrial targeting of DIAP1 alone is not sufficient for degradation and requires Reaper binding. Conversely, Reaper able to bind IAPs, but lacking a mitochondrial targeting GH3 domain (DeltaGH3 Reaper), can induce DIAP1 turnover only if DIAP1 is otherwise targeted to membranes. Surprisingly, targeting DIAP1 to the endoplasmic reticulum instead of mitochondria is partially effective in allowing DeltaGH3 Reaper to promote DIAP1 degradation, suggesting that co-localization of DIAP and Reaper at a membrane surface is critical for the induction of DIAP degradation. Collectively, these data provide a specific function for the GH3 domain in conferring protein-lipid interactions, demonstrate that both Reaper binding and mitochondrial localization are required for accelerated IAP degradation, and suggest that membrane localization per se contributes to DIAP1 auto-ubiquitination and degradation.

Duke Scholars

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

January 4, 2008

Volume

283

Issue

1

Start / End Page

367 / 379

Location

United States

Related Subject Headings

  • Xenopus
  • Ubiquitination
  • Recombinant Fusion Proteins
  • Protein Binding
  • Mitochondrial Membranes
  • Mitochondria
  • Microscopy, Confocal
  • Membrane Lipids
  • Liposomes
  • Inhibitor of Apoptosis Proteins
 

Citation

APA
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ICMJE
MLA
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Freel, C. D., Richardson, D. A., Thomenius, M. J., Gan, E. C., Horn, S. R., Olson, M. R., & Kornbluth, S. (2008). Mitochondrial localization of Reaper to promote inhibitors of apoptosis protein degradation conferred by GH3 domain-lipid interactions. J Biol Chem, 283(1), 367–379. https://doi.org/10.1074/jbc.M708931200
Freel, Christopher D., D Ashley Richardson, Michael J. Thomenius, Eugene C. Gan, Sarah R. Horn, Michael R. Olson, and Sally Kornbluth. “Mitochondrial localization of Reaper to promote inhibitors of apoptosis protein degradation conferred by GH3 domain-lipid interactions.J Biol Chem 283, no. 1 (January 4, 2008): 367–79. https://doi.org/10.1074/jbc.M708931200.
Freel CD, Richardson DA, Thomenius MJ, Gan EC, Horn SR, Olson MR, et al. Mitochondrial localization of Reaper to promote inhibitors of apoptosis protein degradation conferred by GH3 domain-lipid interactions. J Biol Chem. 2008 Jan 4;283(1):367–79.
Freel, Christopher D., et al. “Mitochondrial localization of Reaper to promote inhibitors of apoptosis protein degradation conferred by GH3 domain-lipid interactions.J Biol Chem, vol. 283, no. 1, Jan. 2008, pp. 367–79. Pubmed, doi:10.1074/jbc.M708931200.
Freel CD, Richardson DA, Thomenius MJ, Gan EC, Horn SR, Olson MR, Kornbluth S. Mitochondrial localization of Reaper to promote inhibitors of apoptosis protein degradation conferred by GH3 domain-lipid interactions. J Biol Chem. 2008 Jan 4;283(1):367–379.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

January 4, 2008

Volume

283

Issue

1

Start / End Page

367 / 379

Location

United States

Related Subject Headings

  • Xenopus
  • Ubiquitination
  • Recombinant Fusion Proteins
  • Protein Binding
  • Mitochondrial Membranes
  • Mitochondria
  • Microscopy, Confocal
  • Membrane Lipids
  • Liposomes
  • Inhibitor of Apoptosis Proteins