Increasing organismal healthspan by enhancing mitochondrial protein quality control.

Degradation of damaged proteins by members of the protein quality control system is of fundamental importance in maintaining cellular homeostasis. In mitochondria, organelles which both generate and are targets of reactive oxygen species (ROS), a number of membrane bound and soluble proteases are essential components of this system. Here we describe the regulation of Podospora anserina LON (PaLON) levels, an AAA(+) family serine protease localized in the matrix fraction of mitochondria. Constitutive overexpression of PaLon results in transgenic strains of the fungal ageing model P. anserina showing increased ATP-dependent serine protease activity. These strains display lower levels of carbonylated (aconitase) and carboxymethylated proteins, reduced secretion of hydrogen peroxide and a higher resistance against exogenous oxidative stress. Moreover, they are characterized by an extended lifespan without impairment of vital functions such as respiration, growth and fertility. The reported genetic manipulation proved to be a successful intervention in organismal ageing and it led to an increase in the healthy lifespan, the healthspan, of P. anserina.