This lecture explores the challenges and mechanisms involved in the import of mitochondrial precursor proteins, focusing on the intermembrane space. It discusses the impact of defects in mitochondrial functionality on various diseases and the role of protein folding in maintaining cellular health. The instructor delves into the cytosolic accumulation of mitochondrial precursors, the role of chaperones in protein import, and the association of Hsp104 with cytosolic clusters. Additionally, yeast models are used to study the aggregation of neurotoxic proteins, shedding light on proteostasis networks and protein degradation pathways within mitochondria.