Fig. 2.

Mitochondrial unfolded protein response (UPR^mt) is proposed to mediate mitochondrial maintenance in cancer. Cancer cells develop mitochondrial dysfunction due to increased accumulation of mtDNA and mtROS relative to non-malignant cells. Although mtROS can be beneficial to cell growth, excess mtROS can damage proteins and further propagate oxidative and proteotoxic stress in the mitochondria. The UPR^mt system refolds proteins so that they return to their proper conformation or cleaves such proteins. This preserves mitochondrial integrity and prevents mitochondrial apoptosis