Correlative cryo-electron microscopy reveals the structure of TNTs in neuronal cells

Anna Sartori-Rupp, Diégo Cordero Cervantes, Anna Pepe, Karine Gousset, Elise Delage, Simon Corroyer-Dulmont, Christine Schmitt, Jacomina Krijnse-Locker & Chiara Zurzolo - Institut Pasteur, Unit of Technology and Service Ultra-structural Bio-Imaging, and Unit of Technology and Service Ultra-structural Bio-Imaging, Paris, France

The orchestration of intercellular communication is essential for multicellular organisms. One mechanism by which cells communicate is through long, actin-rich membranous protrusions called tunneling nanotubes (TNTs), which allow the intercellular transport of various cargoes, between the cytoplasm of distant cells in vitro and in vivo. Here, we use correlative FIB-SEM, light- and cryo-electron microscopy approaches to elucidate the structural organization of neuronal TNTs. Our data indicate that they are composed of a bundle of open-ended individual tunneling nanotubes (iTNTs) that are held together by threads labeled with anti-N-Cadherin antibodies. iTNTs are filled with parallel actin bundles on which different membrane-bound compartments and mitochondria appear to transfer. These results provide evidence that neuronal TNTs have distinct structural features compared to other cell protrusions.

How Amira-Avizo Software is used

We thank (…) Remi Blanc from Amira for the automated segmentation of actin using the XTracing—Filament detection module.