Newly-discovered signal in the cell sets protein pathways to mitochondria

Mitochondria are often described as the powerhouse in the cells of humans, plants and animals; but they also fulfill a number of other vital functions. These “organs” within the cell have an interesting past: They arose more than a billion years ago as a bacterium, which was adopted into a primeval cell. In the course of evolution, nearly all the genes of the original bacterium have become part of the cell nucleus. One result of this is that most of the protein building-blocks in mitochondria are produced in the cell plasma and put in place via complex importation processes.