Lucas Cranach the Elder [Public domain] via Wikimedia CommonsAging can be broadly defined as a gradual decline in function over time; it is one of the most conserved features of living organisms. Mitochondrial dysfunction is a hallmark of aging, but the mechanisms contributing to the disruption of mitochondrial homeostasis are not clearly understood. Now, researchers led by David Sinclair (Harvard Medical School, Boston, MA) report that a disruption of intracellular communication between the mitochondria and nucleus contributes to aging-related mitochondrial dysfunction.