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Structure of the 48-nm repeat doublet microtubule from bovine tracheal cilia
Structural highlights
FunctionCFA95_BOVIN Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) in cilia axoneme, which is required for motile cilia beating.[1] Publication Abstract from PubMedDynein-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. De novo identification of mammalian ciliary motility proteins using cryo-EM.,Gui M, Farley H, Anujan P, Anderson JR, Maxwell DW, Whitchurch JB, Botsch JJ, Qiu T, Meleppattu S, Singh SK, Zhang Q, Thompson J, Lucas JS, Bingle CD, Norris DP, Roy S, Brown A Cell. 2021 Nov 11;184(23):5791-5806.e19. doi: 10.1016/j.cell.2021.10.007. Epub , 2021 Oct 28. PMID:34715025[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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