A brief history of the discovery of the mitochondrial unfolded protein response in mammalian cells

Cells have responded to stresses which cause proteins to come out of solution by evolving unfolded protein response mechanisms. In eukaryotic cells there are several such mechanisms covering the whole cell and sub-celllular organelles. This review describes discoveries that describe the unfolded protein response in the matrix compartment of mitochondria (mtUPRR) of mammalian cells.