Enhanced mitochondrial biogenesis is associated with increased expression of the mitochondrial ATP-dependent Lon protease

Rats bearing the Zajdela hepatoma tumor and T3-treated hypothyroid rats wer e used to study the role of protein degradation in the process of mitochond rial biogenesis, It was shown that the activity, protein and mRNA levels of the ATP-dependent Lon protease increased in rapidly growing Zajdela hepato ma cells. The increase in the rate of mitochondrial biogenesis by thyroid h ormone was similarly accompanied by enhanced expression of the Lon protease , The results imply that mitochondrial biogenesis in mammalian cells is, at least partially, regulated by the matrix Lon protease, (C) 1999 Federation of European Biochemical Societies.