Mitochondrial localization of μ-calpain

Matthew Garcia, Vimala Bondada, James W. Geddes

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Calcium-dependent cysteine proteases, calpains, have physiological roles in cell motility and differentiation but also play a pathological role following insult or disease. The ubiquitous calpains are widely considered to be cytosolic enzymes, although there has been speculation of a mitochondrial calpain. Within a highly enriched fraction of mitochondria obtained from rat cortex and SH-SY5Y human neuroblastoma cells, immunoblotting demonstrated enrichment of the 80 kDa μ-calpain large subunit and 28 kDa small subunit. In rat cortex, antibodies against domains II and III of the large μ-calpain subunit also detected a 40 kDa fragment, similar to the autolytic fragment generated following incubation of human erythrocyte μ-calpain with Ca2+. Mitochondrial proteins including apoptosis inducing factor and mitochondrial Bax are calpain substrates, but the mechanism by which calpains gain access to these proteins is uncertain. Mitochondrial localization of μ-calpain places the enzyme in proximity to its mitochondrial substrates and to Ca2+ released from mitochondrial stores.

Original languageEnglish
Pages (from-to)1241-1247
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number2
StatePublished - Dec 16 2005

Bibliographical note

Funding Information:
This research was supported by grants from the National Institutes of Health (NS045726, AG10836, J.W.G.) and from the Kentucky Spinal Cord and Head Injury Research Trust (J.W.G.).


  • Apoptosis
  • Apoptosis inducing factor
  • Bax
  • Calcium
  • Cell death
  • Cortex
  • Necrosis
  • Neuroblastoma
  • Permeability transition
  • Protease

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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