Mitochondria move in on calcium

Mitochondria aren't just ATP factories. They serve as important components in intracellular signaling by modulating Ca²⁺ and act as a relay system in apoptosis. And they are dynamic organelles, moving about the cell at a rapid pace. On page 661, Yi et al. integrate these observations by demonstrating that local Ca²⁺ concentration controls mitochondrial movement.

Initially, the team was focused on the local interactions between the endoplasmic reticulum (ER) and mitochondria in myoblast cells in culture, but then noticed that changes in Ca²⁺ induced massive fluctuations in the rate of mitochondrial movement. To quantify these changes, the team labeled mitochondria with YFP fused to a mitochondrial targeting sequence. Stimulating the cells with vasopressin, a Ca²⁺ mobilizing hormone, or inducing localized Ca²⁺ release from the ER using...