Mitochondrial Unfolded Protein Responses in White Adipose Tissue: Lipoatrophy, Whole-Body Metabolism and Lifespan.

The mitochondrial unfolded protein response (UPR) is a stress response mediated by the expression of genes such as chaperones, proteases, and mitokines to maintain mitochondrial proteostasis. Certain genetically modified mice, which defect mitochondrial proteins specifically in adipocytes, developed atrophy of the white adipose tissue, resisted diet-induced obesity, and had altered whole-body metabolism. UPR, which has beneficial functions for living organisms, is termed "mitohormesis", but its specific characteristics and detailed regulatory mechanism have not been elucidated to date. In this review, we discuss the function of UPR in adipose atrophy (lipoatrophy), whole-body metabolism, and lifespan based on the concept of mitohormesis.