Miro1: new wheels for transferring mitochondria.

Mesenchymal stem cells (MSC) are capable of protecting cells harboring mitochondrial damage. This protection is associated with the transfer of mitochondria through tunneling nanotubes (TNT) from MSC to the injured cells. In this issue of The EMBO Journal, the group of Anurag Agrawal shows that mitochondrial transfer is dependent on the levels of Miro1, a mitochondrial Rho-GTPase that regulates intercellular mitochondrial movement. Miro1 is the first protein shown to accelerate mitochondrial transfer. Amplifying the mitochondrial transfer phenomenon may allow for the study of the mechanisms that regulate it and contribute to our understanding of its role in disease and aging.