FIGURE 1.

Failed mitochondrial import activates proteostatic surveillance. Several pathways in the cell monitor mitochondrial import and are activated by its failure, including the UPR^mt, the PINK1/parkin mitophagic axis, and the DELE1‐HRI pathway. Although the details vary (see text), these pathways are generally activated when proteins are not properly imported into mitochondria. Often this serves as a direct signal of mitochondrial damage, stimulating transcriptional changes to restore homeostasis, limit protein translation and import, promote mitochondrial recycling via mitophagy, and even activate cell death pathways. Abbreviations: MTS—mitochondrial targeting sequence, NLS—nuclear localization signal, P—Parkin, and Ub—ubiquitin