Quality control in mitochondria: use it, break it, fix it, trash it.

Repairing or disposing of a malfunctioning object is an everyday dilemma. Replacing an item may be quicker than repairing it, but may also be more costly. Cells are faced with the same options when their organelles are challenged. Ensuring the health of the mitochondrial network is of utmost importance for cellular health and, not surprisingly, mitochondrial quality control can take both the repair and disposal routes. Spectacular advances have been made in recent years and a picture is starting to emerge of what drives a cell to take one or the other path. Interestingly, mitochondrial quality control seems to be deficient in various medically relevant conditions, such as neurodegeneration and aging.