Gui, MiaoMiaoGuiFarley, HannahHannahFarleyAnujan, PriyankaPriyankaAnujanAnderson, Jacob RJacob RAndersonMaxwell, Dale WDale WMaxwellWhitchurch, Jonathan BJonathan BWhitchurchBotsch, J JosephineJ JosephineBotschQiu, TaoTaoQiuMeleppattu, ShimiShimiMeleppattuSingh, Sandeep KSandeep KSinghZhang, QiQiZhangThompson, JamesJamesThompsonLucas, Jane SJane SLucasBingle, Colin DColin DBingleNorris, Dominic PDominic PNorrisRoy, SudiptoSudiptoRoyBrown, AlanAlanBrown2022-01-172022-01-172021-11-11Cell, 2021, 184 (23), pp.5791-5806.e190092-8674http://hdl.handle.net/10044/1/93627Dynein-decorated doublet microtubules (DMTs) are critical components of the oscillatory molecular machine of cilia, the axoneme, and have luminal surfaces patterned periodically by microtubule inner proteins (MIPs). Here we present an atomic model of the 48-nm repeat of a mammalian DMT, derived from a cryoelectron microscopy (cryo-EM) map of the complex isolated from bovine respiratory cilia. The structure uncovers principles of doublet microtubule organization and features specific to vertebrate cilia, including previously unknown MIPs, a luminal bundle of tektin filaments, and a pentameric dynein-docking complex. We identify a mechanism for bridging 48- to 24-nm periodicity across the microtubule wall and show that loss of the proteins involved causes defective ciliary motility and laterality abnormalities in zebrafish and mice. Our structure identifies candidate genes for diagnosis of ciliopathies and provides a framework to understand their functions in driving ciliary motility.© 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Science & TechnologyLife Sciences & BiomedicineBiochemistry & Molecular BiologyCell BiologyARM-DOCKING COMPLEXLEFT-RIGHT ASYMMETRYOUTER ARMSITUS-INVERSUSDOUBLET MICROTUBULESCOILED-COILTEKTIN 3DYNEINMUTATIONSGENEJournal Articlehttps://www.dx.doi.org/10.1016/j.cell.2021.10.007https://www.sciencedirect.com/science/article/pii/S0092867421011818?via%3Dihub1097-4172