Cellular protein traffic: Signalling pathways regulating mitochondrial protein import

Abstract

Mitochondria have to import most of their proteins in order to fulfill a multitude of metabolic functions. Sophisticated import machineries mediate targeting and translocation of preproteins from the cytosol and their subsequent sorting into the suborganellar destination. For a long time the mode of action of these machineries has been considered as a static and constitutively active process. We found that the preprotein import machinery is highly phosphorylated and targeted by several cytosolic and mitochondrial protein kinases. They dynamically regulate organellar protein import to adjust the specific requirements of mitochondria to changes in metabolic conditions. Moreover, we uncovered the first link between cell cycle regulation and the mitochondrial import machinery.