Bacteria display an array of contact-dependent interaction systems that have evolved to facilitate direct cell-to-cell communication. We have previously identified a mode of bacterial communication mediated by nanotubes bridging neighboring cells. Here, we elucidate nanotube architecture, dynamics, and molecular components. Utilizing Bacillus subtilis as a model organism, we found that at low cell density, nanotubes exhibit remarkable complexity, existing as both intercellular tubes and extending tubes, with the latter frequently surrounding the cells in a "root-like" fashion. Observing nanotube formation in real time showed that these structures are formed in the course of minutes, displaying rapid movements. Utilizing a combination of super-resolution, light, and electron microscopy, we revealed that nanotubes are composed of chains of membranous segments harboring a continuous lumen. Furthermore, we discovered that a conserved calcineurin-like protein, YmdB, presents in nanotubes and is required for both nanotube production and intercellular molecular trade.
Bibliographical noteFunding Information:
We are grateful to I. Popov, E. Blayvas, A. Radko, S. Eliav, G. Chechelnitsky, M. Saidian, V. Gutkin (NanoCentre, Hebrew University), and the Center for Microscopy and Image Analysis, (Zurich University) for technical support. We are indebted to members of the Ben-Yehuda laboratory, G. Bachrach, I. Rosenshine, A. Taraboulos and J. Thrissur (Hebrew University), A.K. Tiwari (IISER), and B. Rosenberg (MIT) for help and valuable discussions. This work is supported by the ERC -Advance Grant ( 339984 ) and the Israel Science Foundation (ISF) (327/11) awarded to S.B.-Y., the Marie Skłodowska-Curie actions of the European Commission ( 321993 ) and the ISF (1937/13) awarded to E.S., the ERC-Starting Grant ( 337713 ) and ISF (843/11) awarded to D.K., and the Maexi foundation support to O.M. G.B.M.M. was supported by PBC -outstanding postdoctoral fellowship, Council for Higher Education, Israel.
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