Mitochondrion biogenesis

Skou, J. C. Mitochondria biogenesis and bioenergetics, Biomembranes molecular arrangements and transport mechanisms, Vol. 28, S. 39, North-Holland, American Elsevier 1972... 

Because Rlil homologs have been found only in archaebacteria (reviewed in Tachezy and Dolezal 2007), it is hypothesized that Rlil and other components of cytosolic translation machinery are derived from them. Therefore, we propose that the intimate association of the relic mitochondrion, of eubacterial origin, with its associated membranes is a structural reflection of the cell s attempt to facilitate efficient ribosome biogenesis and translation initiation following reductive evolution of the organelle (Keeling 2004 ... 

In the mitochondrion it participates in ketone body synthesis, while as a cytoplasmic enzyme it functions in cholesterol biogenesis [22],... 

T. Wenz, Regulation of mitochondrial biogenesis and PGC-lalpha under cellular stress. Mitochondrion, 13 (2013) 134-42. 

These facts bring us to one of the major outstanding problems in mitochondrial biogenesis what is the mechanism whereby the vast majority of mitochondrial proteins, coded for by nuclear DNA and synthesized on cytoplasmic ribosomes, traverse the mitochondrial membrane barriers and enter the closed organelle Since the mitochondrion is impermeable to proteins of even relatively low molecular weight, a number of models have been proposed to account for the transport of products of cytoplasmic protein synthesis into mitochondria, but convincing experimental support for these is not yet available. 

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