Effect of Lon protease knockdown on mitochondrial function in HeLa cells

Biochimie. 2014 May;100:38-47. doi: 10.1016/j.biochi.2013.12.005. Epub 2013 Dec 17.


ATP-dependent proteases are currently emerging as key regulators of mitochondrial functions. Among these proteolytic systems, Lon protease is involved in the control of selective protein turnover in the mitochondrial matrix. In the absence of Lon, yeast cells have been shown to accumulate electron-dense inclusion bodies in the matrix space, to loose integrity of mitochondrial genome and to be respiratory deficient. In order to address the role of Lon in mitochondrial functionality in human cells, we have set up a HeLa cell line stably transfected with a vector expressing a shRNA under the control of a promoter which is inducible with doxycycline. We have demonstrated that reduction of Lon protease results in a mild phenotype in this cell line in contrast with what have been observed in other cell types such as WI-38 fibroblasts. Nevertheless, deficiency in Lon protease led to an increase in ROS production and to an accumulation of carbonylated protein in the mitochondria. Our study suggests that Lon protease has a wide variety of targets and is likely to play different roles depending of the cell type.

Keywords: Cellular redox status; HeLa cells; Lon protease; Mitochondria; Protein oxidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Doxycycline / pharmacology
  • Fibroblasts / cytology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Gene Expression Regulation
  • HeLa Cells
  • Humans
  • Mitochondria / genetics*
  • Mitochondria / metabolism
  • Mitochondrial Proteins / antagonists & inhibitors
  • Mitochondrial Proteins / genetics*
  • Mitochondrial Proteins / metabolism
  • Organ Specificity
  • Oxidation-Reduction
  • Oxidative Phosphorylation
  • Phenotype
  • Promoter Regions, Genetic / drug effects
  • Protease La / antagonists & inhibitors
  • Protease La / genetics*
  • Protease La / metabolism
  • Protein Carbonylation / drug effects
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Reactive Oxygen Species / metabolism


  • Mitochondrial Proteins
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Protease La
  • Doxycycline