Posttranscriptional control of mitochondrial biogenesis: spatio-temporal regulation of the protein import process.

This review focuses on the posttranscriptional processes which govern mitochondrial biogenesis, with a special emphasis on the asymmetric localization-translation of nuclear-encoded mRNAs as an important regulatory step of the protein import process. We review how spatio-temporal mRNA regulons help to elicit timely, versatile, and coordinated intracellular processes to assemble mitochondrial structures. Our current knowledge on the mitochondrial import of respiratory chain assembly factors and the role of the ribonucleic acid (RNA) binding protein Puf3 are presented. A connection with the target of rapamycine signalling pathway may explain how respiratory chain assembly senses environmental conditions via the protein import machinery.