This conversation with mitochondrial biologist Navdeep S. Chandel (Northwestern University) is part of Cold Spring Harbor Laboratory’s “Leading Strand”—CSHL’s official interview series that accompanies its world-renowned programs. In this installment, from the 89th Cold Spring Harbor Laboratory Symposium on Quantitative Biology: Senescence & Aging, Chandel discusses how mitochondria function not only as energy producers but as signal-generating organelles.