Tunneling nanotubes under the microscope

Cell Biology Long, actin-rich membranous protrusions called tunneling nanotubes (TNTs) allow the intercellular transport of various cargos, including viruses, organelles, and proteins. Sartori-Rupp et al. report the structural characterization of TNTs formed between neuronal cells in culture using correlative light- and cryo–electron microscopy approaches. They found that TNTs are distinct from other actin-rich cell protrusions like filopodia. TNTs are composed of a bundle of functional individual tunneling nanotubes containing membrane-bound compartments, including mitochondria. Bridging threads between the individual nanotubes contained the cell adhesion molecule N-cadherin. Nat. Commun. 10 , 342 (2019).