Noncoding RNAs regulatory network in mitochondria
Mitochondria are powerhouses of eukaryotic cells and possess own bioenergetically specialized genetic system also known as mitochondrial DNA (mtDNA). In human cells, mtDNA encodes 22 transfer RNAs, 2 ribosomal RNAs and 13 proteins which are subunits of the oxidative phosphorylation machinery. Due to the small size of the mitochondrial genome, mitochondrial biogenesis and function are largely dependent on a number of nuclear-encoded molecules that are imported to mitochondria via the translocase of the outer mitochondrial membrane complex. In line with that, the mitochondrial proteome and transcriptome landscape represents an intricate mixture of intrinsic (i.e. mitochondrial) and extrinsic (i.e. nuclear-encoded) molecules. Thus, mitochondrial metabolism, as well as cellular homeostasis, require coordination of expression of two genomes and well-tuned cross-talk between the nucleus and mitochondria [Figure 1].