Cryo‐electron tomography elucidates annular intraluminal configurations in Caenorhabditis elegans microtubules

• Published in: Biology of the cell Vol. 116; no. 9; pp. e2400064 - n/a
• Main Authors: Zhu, Hao, Li, Ming, Li, Meijing, Li, Xueming, Ou, Guangshuo
• Format: Journal Article
• Language: English
• Published: England 01.09.2024
• Subjects: Animals; Caenorhabditis elegans - metabolism; Caenorhabditis elegans - ultrastructure; Caenorhabditis elegans Proteins - metabolism; Cryoelectron Microscopy - methods; Electron Microscope Tomography - methods; Larva - ultrastructure; Microtubules - metabolism; Microtubules - ultrastructure; Tubulin - metabolism
• ISSN: 0248-4900; 1768-322X; 1768-322X
• DOI: 10.1111/boc.202400064

Background information Microtubules serve as integral components in cellular operations such as cell division, intracellular trafficking, and cellular architecture. Composed of tubulin protein subunits, these hollow tubular structures have been increasingly elucidated through advanced cryo‐electron microscopy (Cryo‐EM), which has unveiled the presence of microtubule inner proteins (MIPs) within the microtubular lumen. Results In the present investigation, we employ a synergistic approach incorporating high‐pressure freezing, cryo‐focused ion beam milling, and Cryo‐electron tomography (Cryo‐ET) to interrogate the in situ architecture of microtubules in Caenorhabditis elegans larvae. Our Cryo‐ET assessments across neuronal cilia and diverse tissue types consistently demonstrate the formation of annular configurations within the microtubular lumen. Conclusions In concert with recently characterized MIPs, our in situ observations within a living organism corroborate the hypothesis that intricate luminal assemblages exist within microtubule scaffolds. These findings necessitate further exploration into the molecular constituents and functional ramifications of these internal microtubular configurations in both cellular physiology and pathophysiology. Using advanced cryo‐electron microscopy techniques, we demonstrate the formation of annular intraluminal configurations within the microtubule lumen across diverse tissue types in Caenorhabditis elegans larvae. Our in situ observations in living organism substantiate the presence of complex luminal structures within microtubule scaffolds, and necessitate further exploration to elucidate the molecular composition of these structures and their functions in both cellular physiology and pathophysiology.