PNPASE and RNA trafficking into mitochondria

► Mitochondrial homeostasis is maintained by PNPASE from an intermembrane space location. ► PNPASE activities in mitochondrial RNA import and RNA processing are separable. ► Imported RNAs are required for mitochondrial genome replication, transcription, and translation. ► PNPASE regulation of mitochondrial metabolism and RNA import are thus far inseparable.