The human cellular kinome contains over 500 kinases, accounting for almost 2% of all our genes. It is currently impossible to gauge the phosphorylation status, or even phosphorylation potential, of the entire proteome of any cell. Mitochondria, on the other hand, use just 25 kinases. Moreover, their entire proteome contains only 1,136 proteins, at least according to the latest version of the Mitocarta Database.