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Journal of Cell Science Jun 2023Flagella are important for eukaryote cell motility, including in sperm, and are vital for life cycle progression of many unicellular eukaryotic pathogens. The '9+2'...
Flagella are important for eukaryote cell motility, including in sperm, and are vital for life cycle progression of many unicellular eukaryotic pathogens. The '9+2' axoneme in most motile flagella comprises nine outer doublet and two central-pair singlet microtubules. T-shaped radial spokes protrude from the outer doublets towards the central pair and are necessary for effective beating. We asked whether there were radial spoke adaptations associated with parasite lineage-specific properties in apicomplexans and trypanosomatids. Following an orthologue search for experimentally uncharacterised radial spoke proteins (RSPs), we identified and analysed RSP9. Trypanosoma brucei and Leishmania mexicana have an extensive RSP complement, including two divergent RSP9 orthologues, necessary for flagellar beating and swimming. Detailed structural analysis showed that neither orthologue is needed for axoneme assembly in Leishmania. In contrast, Plasmodium has a reduced set of RSPs including a single RSP9 orthologue, deletion of which in Plasmodium berghei leads to failure of axoneme formation, failed male gamete release, greatly reduced fertilisation and inefficient life cycle progression in the mosquito. This indicates contrasting selection pressures on axoneme complexity, likely linked to the different mode of assembly of trypanosomatid versus Plasmodium flagella.
Topics: Male; Animals; Axoneme; Parasites; Microtubules; Seeds; Proteins; Flagella; Eukaryota; Plasmodium; Dyneins
PubMed: 37288670
DOI: 10.1242/jcs.260655 -
Current Biology : CB Jun 2008Axonemes of motile eukaryotic cilia and flagella have a conserved structure of nine doublet microtubules surrounding a central pair of microtubules. Outer and inner...
Axonemes of motile eukaryotic cilia and flagella have a conserved structure of nine doublet microtubules surrounding a central pair of microtubules. Outer and inner dynein arms on the doublets mediate axoneme motility [1]. Outer dynein arms (ODAs) attach to the doublets at specific interfaces [2-5]. However, the molecular contacts of ODA-associated proteins with tubulins of the doublet microtubules are not known. We report here that attachment of ODAs requires glycine 56 in the beta-tubulin internal variable region (IVR). We show that in Drosophila spermatogenesis, a single amino acid change at this position results in sperm axonemes markedly deficient in ODAs. Moreover, we found that axonemal beta-tubulins throughout the phylogeny have invariant glycine 56 and a strongly conserved IVR, whereas nonaxonemal beta-tubulins vary widely in IVR sequences. Our data reveal a deeply conserved physical requirement for assembly of the macromolecular architecture of the motile axoneme. Amino acid 56 projects into the microtubule lumen [6]. Imaging studies of axonemes indicate that several proteins may interact with the doublet-microtubule lumen [3, 4, 7, 8]. This region of beta-tubulin may determine the conformation necessary for correct attachment of ODAs, or there may be sequence-specific interaction between beta-tubulin and a protein involved in ODA attachment or stabilization.
Topics: Amino Acid Sequence; Animals; Axoneme; Drosophila; Dyneins; Glycine; Male; Molecular Sequence Data; Protein Conformation; Spermatogenesis; Spermatozoa; Tomography, X-Ray Computed; Tubulin
PubMed: 18571413
DOI: 10.1016/j.cub.2008.05.031 -
Current Biology : CB Sep 2010Centrioles are conserved microtubule-based organelles that lie at the core of the animal centrosome and play a crucial role in nucleating the formation of cilia and... (Review)
Review
Centrioles are conserved microtubule-based organelles that lie at the core of the animal centrosome and play a crucial role in nucleating the formation of cilia and flagella in most eukaryotes. Centrioles have a complex ultrastructure with ninefold symmetry and a well-defined length. This structure is assembled from a host of proteins, including a variety of disease gene products. Over a century after the discovery of centrioles, the mechanisms underlying the assembly of these fascinating organelles, in particular the establishment of ninefold symmetry and the control of centriole length, are now starting to be uncovered.
Topics: Animals; Axoneme; Centrioles; Cilia; Flagella; Humans; Microtubules; Models, Biological; Phylogeny
PubMed: 20869612
DOI: 10.1016/j.cub.2010.08.010 -
Sub-cellular Biochemistry 2022Cilia are tail-like organelles responsible for motility, transportation, and sensory functions in eukaryotic cells. Cilia research has been providing multifaceted...
Cilia are tail-like organelles responsible for motility, transportation, and sensory functions in eukaryotic cells. Cilia research has been providing multifaceted questions, attracting biologists of various areas and inducing interdisciplinary studies. In this chapter, we mainly focus on efforts to elucidate the molecular mechanism of ciliary beating motion, a field of research that has a long history and is still ongoing. We also overview topics closely related to the motility mechanism, such as ciliogenesis, cilia-related diseases, and sensory cilia. Subnanometer-scale to submillimeter-scale 3D imaging of the axoneme and the basal body resulted in a wide variety of insights into these questions.
Topics: Axoneme; Cilia; Flagella
PubMed: 36151386
DOI: 10.1007/978-3-031-00793-4_15 -
Cell Motility and the Cytoskeleton Apr 2008Drosophila melanogaster sperm tubulins are posttranslationally glutamylated and glycylated. We show here that axonemes are the substrate for these tubulin C-terminal...
Drosophila melanogaster sperm tubulins are posttranslationally glutamylated and glycylated. We show here that axonemes are the substrate for these tubulin C-terminal modifications. Axoneme architecture is required, but full length, motile axonemes are not necessary. Tubulin glutamylation occurs during or shortly after assembly into the axoneme; only glutamylated tubulins are glycylated. Tubulins in other testis microtubules are not modified. Only a small subset of total Drosophila sperm axoneme tubulins have these modifications. Biochemical fractionation of Drosophila sperm showed that central pair and accessory microtubules have the majority of poly-modified tubulins, whereas doublet microtubules have only small amounts of mono- and oligo-modified tubulins. Glutamylation patterns for different beta-tubulins experimentally assembled into axonemes were consistent with utilization of modification sites corresponding to those identified in other organisms, but surrounding sequence context was also important. We compared tubulin modifications in the 9 + 9 + 2 insect sperm tail axonemes of Drosophila with the canonical 9 + 2 axonemes of sperm of the sea urchin Lytichinus pictus and the 9 + 0 motile sperm axonemes of the eel Anguilla japonica. In contrast to Drosophila sperm, L. pictus sperm have equivalent levels of modified tubulins in both doublet and central pair microtubule fractions, whereas the doublets of A. japonica sperm exhibit little glutamylation but extensive glycylation. Tubulin C-terminal modifications are a prevalent feature of motile axonemes, but there is no conserved pattern for placement or amount of these
Topics: Anguilla; Animals; Axoneme; Drosophila melanogaster; Glutamic Acid; Male; Microscopy, Electron, Transmission; Microtubules; Sea Urchins; Sperm Tail; Spermatozoa; Tubulin
PubMed: 18205200
DOI: 10.1002/cm.20261 -
Nature Communications Dec 2018Defective ciliogenesis causes human developmental diseases termed ciliopathies. Microtubule (MT) asters originating from centrosomes in mitosis ensure the fidelity of...
Defective ciliogenesis causes human developmental diseases termed ciliopathies. Microtubule (MT) asters originating from centrosomes in mitosis ensure the fidelity of cell division by positioning the spindle apparatus. However, the function of microtubule asters in interphase remains largely unknown. Here, we reveal an essential role of MT asters in transition zone (TZ) assembly during ciliogenesis. We demonstrate that the centrosome protein FSD1, whose biological function is largely unknown, anchors MT asters to interphase centrosomes by binding to microtubules. FSD1 knockdown causes defective ciliogenesis and affects embryonic development in vertebrates. We further show that disruption of MT aster anchorage by depleting FSD1 or other known anchoring proteins delocalizes the TZ assembly factor Cep290 from centriolar satellites, and causes TZ assembly defects. Thus, our study establishes FSD1 as a MT aster anchorage protein and reveals an important function of MT asters anchored by FSD1 in TZ assembly during ciliogenesis.
Topics: Animals; Axoneme; Centrosome; Cilia; Humans; Microtubules; Mitosis; Nerve Tissue Proteins; Spindle Apparatus; Zebrafish
PubMed: 30538248
DOI: 10.1038/s41467-018-07664-2 -
Cold Spring Harbor Perspectives in... Jun 2017Tubulin undergoes several highly conserved posttranslational modifications (PTMs) including acetylation, detyrosination, glutamylation, and glycylation. These PTMs... (Review)
Review
Tubulin undergoes several highly conserved posttranslational modifications (PTMs) including acetylation, detyrosination, glutamylation, and glycylation. These PTMs accumulate on a subset of microtubules that are long-lived, including those in the basal bodies and axonemes. Tubulin PTMs are distributed nonuniformly. In the outer doublet microtubules of the axoneme, the B-tubules are highly enriched in the detyrosinated, polyglutamylated, and polyglycylated tubulin, whereas the A-tubules contain mostly unmodified tubulin. The nonuniform patterns of tubulin PTMs may functionalize microtubules in a position-dependent manner. Recent studies indicate that tubulin PTMs contribute to the assembly, disassembly, maintenance, and motility of cilia. In particular, tubulin glutamylation has emerged as a key PTM that affects ciliary motility through regulation of axonemal dynein arms and controls the stability and length of the axoneme.
Topics: Acetylation; Animals; Axonemal Dyneins; Axoneme; Cell Movement; Cilia; Diffusion; Glutamine; Microtubules; Protein Binding; Protein Conformation; Protein Processing, Post-Translational; Tetrahymena; Tubulin; Tyrosine
PubMed: 28003186
DOI: 10.1101/cshperspect.a028159 -
Annual Review of Physiology 2015A characteristic feature of the human airway epithelium is the presence of ciliated cells bearing motile cilia, specialized cell surface projections containing axonemes... (Review)
Review
A characteristic feature of the human airway epithelium is the presence of ciliated cells bearing motile cilia, specialized cell surface projections containing axonemes composed of microtubules and dynein arms, which provide ATP-driven motility. In the airways, cilia function in concert with airway mucus to mediate the critical function of mucociliary clearance, cleansing the airways of inhaled particles and pathogens. The prototypical disorder of respiratory cilia is primary ciliary dyskinesia, an inherited disorder that leads to impaired mucociliary clearance, to repeated chest infections, and to the progressive destruction of lung architecture. Numerous acquired lung diseases are also marked by abnormalities in both cilia structure and function. In this review we summarize current knowledge regarding airway ciliated cells and cilia, how they function to maintain a healthy epithelium, and how disorders of cilia structure and function contribute to inherited and acquired lung disease.
Topics: Animals; Axoneme; Cilia; Ciliary Motility Disorders; Disease Models, Animal; Humans; Lung Diseases; Mice; Microtubules; Mucociliary Clearance; Respiratory Mucosa
PubMed: 25386990
DOI: 10.1146/annurev-physiol-021014-071931 -
Seminars in Cell & Developmental Biology Feb 2021Cilia and centrosomes of eukaryotic cells play important roles in cell movement, fluid transport, extracellular sensing, and chromosome division. The physiological... (Review)
Review
Cilia and centrosomes of eukaryotic cells play important roles in cell movement, fluid transport, extracellular sensing, and chromosome division. The physiological functions of cilia and centrosomes are generated by their dynamics, motions, and forces controlled by the physical, chemical, and biological environments. How an individual cilium achieves its beat pattern and induces fluid flow is governed by its ultrastructure as well as the coordination of associated molecular motors. Thus, a bottom-up understanding of the physiological functions of cilia and centrosomes from the molecular to tissue levels is required. Correlations between the structure and motion can be understood in terms of mechanics. This review first focuses on cilia and centrosomes at the molecular level, introducing their ultrastructure. We then shift to the organelle level and introduce the kinematics and mechanics of cilia and centrosomes. Next, at the tissue level, we introduce nodal ciliary dynamics and nodal flow, which play crucial roles in the organogenetic process of left-right asymmetry. We also introduce respiratory ciliary dynamics and mucous flow, which are critical for protecting the epithelium from drying and exposure to harmful particles and viruses, i.e., respiratory clearance function. Finally, we discuss the future research directions in this field.
Topics: Axonemal Dyneins; Axoneme; Basal Bodies; Biological Transport; Biomechanical Phenomena; Centrosome; Chromosome Segregation; Cilia; Epithelial Cells; Gene Expression; Humans; Microtubules; Movement; Organogenesis; Respiration; Rheology
PubMed: 32307225
DOI: 10.1016/j.semcdb.2020.03.007 -
Nature Structural & Molecular Biology Dec 2021
Topics: Axoneme; Cilia; Cryoelectron Microscopy; Microtubule Proteins; Molecular Motor Proteins; Protein Conformation
PubMed: 34887563
DOI: 10.1038/s41594-021-00701-7