Cilia are microtubule-based sensing hubs that rely on intraflagellar transport (IFT) for their development, maintenance, and function. Kinesin-2 motors transport IFT trains, consisting of IFT proteins and cargo, from ciliary base to tip. There, trains turn around and are transported back by IFT dynein. The mechanism of tip turnaround has remained elusive. Here, we employ single-molecule fluorescence microscopy of IFT components in the tips of phasmid cilia of living C. elegans. Analysis of the trajectories reveals that while motor proteins and IFT-A particle component CHE-11 mostly turn around immediately, the IFT-B particle component OSM-6 pauses for several seconds. Our data indicate that IFT trains disassemble into at least IFT-A, IFT-B, IFT-dynein, and OSM-3 complexes at the tip, where OSM-6 is temporarily retained or undergoes modification, prior to train reassembly and retrograde transport. The single-molecule approach used here is a valuable tool to study how directional switches occur in microtubule-based transport processes.
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http://dx.doi.org/10.1016/j.celrep.2018.10.050 | DOI Listing |
Cytoskeleton (Hoboken)
January 2025
Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka, Japan.
Dyneins are huge motor protein complexes that are essential for cell motility, cell division, and intracellular transport. Dyneins are classified into three major subfamilies, namely cytoplasmic, intraflagellar-transport (IFT), and ciliary dyneins, based on their intracellular localization and functions. Recently, several near-atomic resolution structures have been reported for cytoplasmic/IFT dyneins.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Molecular, Cellular, and Biomedical Sciences, College of Life Sciences and Agriculture, University of New Hampshire, Durham, NH, 03824, USA.
Reprod Biomed Online
July 2024
Department of Gynaecology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China. Electronic address:
Cilia in the fallopian tubes (CFT) play an important role in female infertility, but have not been explored comprehensively. This review reveals the detection techniques for CFT function and morphology, and the related analysis of female infertility and other gynaecological disorders. CFT differentiate from progenitor cells, and develop into primary cilia and motile cilia.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390.
Brain neurons utilize the primary cilium as a privileged compartment to detect and respond to extracellular ligands such as Sonic hedgehog (SHH). However, cilia in cerebellar granule cell (GC) neurons disassemble during differentiation through ultrastructurally unique intermediates, a process we refer to as cilia deconstruction. In addition, mature neurons do not reciliate despite having docked centrioles.
View Article and Find Full Text PDFDev Cell
December 2024
Department of Molecular Biosciences, University of Texas, Austin, Austin, TX 78712, USA. Electronic address:
Motile cilia are ancient, evolutionarily conserved organelles whose dysfunction underlies motile ciliopathies, a broad class of human diseases. Motile cilia contain a myriad of different proteins that assemble into an array of distinct machines, and understanding the interactions and functional hierarchies among them presents an important challenge. Here, we defined the protein interactome of motile axonemes using cross-linking mass spectrometry in Tetrahymena thermophila.
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