Regulation of mitochondrial protein import by the nucleotide exchange factors GrpEL1 and GrpEL2 in human cells.

Mitochondria are organelles indispensable for maintenance of cellular energy homeostasis. Most mitochondrial proteins are nuclearly encoded and are imported into the matrix compartment where they are properly folded. This process is facilitated by the mitochondrial heat shock protein 70 (mtHsp70), a chaperone contributing to mitochondrial protein quality control.