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International Journal of Molecular... Dec 2019The outer and inner dynein arms (ODAs and IDAs) are composed of multiple subunits including dynein heavy chains possessing a motor domain. These complex structures are... (Review)
Review
The outer and inner dynein arms (ODAs and IDAs) are composed of multiple subunits including dynein heavy chains possessing a motor domain. These complex structures are preassembled in the cytoplasm before being transported to the cilia. The molecular mechanism(s) controlling dynein arms' preassembly is poorly understood. Recent evidence suggests that canonical R2TP complex, an Hsp-90 co-chaperone, in cooperation with dynein axonemal assembly factors (DNAAFs), plays a crucial role in the preassembly of ODAs and IDAs. Here, we have summarized recent data concerning the identification of novel chaperone complexes and their role in dynein arms' preassembly and their association with primary cilia dyskinesia (PCD), a human genetic disorder.
Topics: Animals; Axoneme; Cilia; Dyneins; HSP90 Heat-Shock Proteins; Humans; Molecular Chaperones
PubMed: 31817850
DOI: 10.3390/ijms20246174 -
Gene Sep 2014A primary cilium is a microtubule-based membranous protrusion found in almost all cell types. A primary cilium has a "9+0" axoneme that distinguishes this ancient... (Review)
Review
A primary cilium is a microtubule-based membranous protrusion found in almost all cell types. A primary cilium has a "9+0" axoneme that distinguishes this ancient organelle from the canonical motile "9+2" cilium. A primary cilium is the sensory center of the cell that regulates cell proliferation and embryonic development. The primary ciliary pocket is a specialized endocytic membrane domain in the basal region. The basal body of a primary cilium exists as a form of the centriole during interphase of the cell cycle. Although conventional thinking suggests that the cell cycle regulates centrosomal changes, recent studies suggest the opposite, that is, centrosomal changes regulate the cell cycle. In this regard, centrosomal kinase Aurora kinase A (AurA), Polo-like kinase 1 (Plk1), and NIMA related Kinase (Nek or Nrk) propel cell cycle progression by promoting primary cilia disassembly which indicates a non-mitotic function. However, the persistence of primary cilia during spermatocyte division challenges the dominate idea of the incompatibility of primary cilia and cell division. In this review, we demonstrate the detailed structure of primary cilia and discuss the relationship between primary cilia disassembly and cell cycle progression on the background of various mitotic kinases.
Topics: Animals; Aurora Kinase A; Axoneme; Cell Cycle Proteins; Cell Division; Cilia; Humans
PubMed: 24971504
DOI: 10.1016/j.gene.2014.06.050 -
Genetics in Medicine : Official Journal... May 2023Primary ciliary dyskinesia (PCD) is a heterogeneous disorder that includes respiratory symptoms, laterality defects, and infertility caused by dysfunction of motile...
PURPOSE
Primary ciliary dyskinesia (PCD) is a heterogeneous disorder that includes respiratory symptoms, laterality defects, and infertility caused by dysfunction of motile cilia. Most PCD-causing variants result in abnormal outer dynein arms (ODAs), which provide the generative force for respiratory ciliary beating and proper mucociliary clearance.
METHODS
In addition to studies in mouse and planaria, clinical exome sequencing and functional analyses in human were performed.
RESULTS
In this study, we identified homozygous pathogenic variants in CLXN (EFCAB1/ODAD5) in 3 individuals with laterality defects and respiratory symptoms. Consistently, we found that Clxn is expressed in mice left-right organizer. Transmission electron microscopy depicted ODA defects in distal ciliary axonemes. Immunofluorescence microscopy revealed absence of CLXN from the ciliary axonemes, absence of the ODA components DNAH5, DNAI1, and DNAI2 from the distal axonemes, and mislocalization or absence of DNAH9. In addition, CLXN was undetectable in ciliary axonemes of individuals with defects in the ODA-docking machinery: ODAD1, ODAD2, ODAD3, and ODAD4. Furthermore, SMED-EFCAB1-deficient planaria displayed ciliary dysmotility.
CONCLUSION
Our results revealed that pathogenic variants in CLXN cause PCD with defects in the assembly of distal ODAs in the respiratory cilia. CLXN should be referred to as ODA-docking complex-associated protein ODAD5.
Topics: Humans; Animals; Mice; Cilia; Kartagener Syndrome; Calcium-Binding Proteins; Axoneme; Mutation; Axonemal Dyneins
PubMed: 36727596
DOI: 10.1016/j.gim.2023.100798 -
The Journal of Cell Biology Feb 2013Despite the critical contributions of cilia to embryonic development and human health, key regulators of cilia formation await identification. In this paper, a...
Despite the critical contributions of cilia to embryonic development and human health, key regulators of cilia formation await identification. In this paper, a functional RNA interference-based screen linked 30 novel protein kinases with ciliogenesis. Of them, we have studied the role of the microtubule (MT)-associated protein/MT affinity regulating kinase 4 (MARK4) in depth. MARK4 associated with the basal body and ciliary axoneme in human and murine cell lines. Ultrastructural and functional analyses established that MARK4 kinase activity was required for initiation of axoneme extension. We identified the mother centriolar protein ODF2 as an interaction partner of MARK4 and showed that ODF2 localization to the centriole partially depended on MARK4. Our data indicated that, upon MARK4 or ODF2 knockdown, the ciliary program arrested before the complete removal of the CP110-Cep97 inhibitory complex from the mother centriole, suggesting that these proteins act at this level of axonemal extension. We propose that MARK4 is a critical positive regulator of early steps in ciliogenesis.
Topics: Animals; Axoneme; Cell Cycle Proteins; Cell Line; Cilia; HEK293 Cells; Heat-Shock Proteins; Humans; Mice; Microtubule-Associated Proteins; Models, Biological; NIH 3T3 Cells; Phosphoproteins; Protein Serine-Threonine Kinases; RNA Interference
PubMed: 23400999
DOI: 10.1083/jcb.201206013 -
Journal of Cell Science Feb 2010The working mechanism of the eukaryotic flagellar axoneme remains one of nature's most enduring puzzles. The basic mechanical operation of the axoneme is now a story... (Review)
Review
The working mechanism of the eukaryotic flagellar axoneme remains one of nature's most enduring puzzles. The basic mechanical operation of the axoneme is now a story that is fairly complete; however, the mechanism for coordinating the action of the dynein motor proteins to produce beating is still controversial. Although a full grasp of the dynein switching mechanism remains elusive, recent experimental reports provide new insights that might finally disclose the secrets of the beating mechanism: the special role of the inner dynein arms, especially dynein I1 and the dynein regulatory complex, the importance of the dynein microtubule-binding affinity at the stalk, and the role of bending in the selection of the active dynein group have all been implicated by major new evidence. This Commentary considers this new evidence in the context of various hypotheses of how axonemal dynein coordination might work.
Topics: Animals; Axoneme; Cilia; Dyneins; Flagella; Humans; Models, Biological; Molecular Motor Proteins; Movement
PubMed: 20145000
DOI: 10.1242/jcs.051326 -
The evolution of sperm axoneme structure and the dynein heavy chain complement in cecidomid insects.Cytoskeleton (Hoboken, N.J.) Apr 2016The 9 + 2 axoneme of cilia and flagella is specialized machinery aimed at the production of efficient, finely tuned motility, and it has been evolutionarily...
The 9 + 2 axoneme of cilia and flagella is specialized machinery aimed at the production of efficient, finely tuned motility, and it has been evolutionarily conserved from protists to mammals. However, the sperm cells of several insects express unconventional axonemes, which represent unique models for studying the structural-functional relationships underlying axonemal function and evolution. Cecidomids comprise a group of dipterans characterized by an overall tendency to deviate from the standard axonemal pattern. In particular, the subfamily Cecidomyiinae shows a series of progressive modifications of the sperm axoneme. We previously analyzed the unusual sperm axonemes of Asphondylia ruebsaameni (Asphondyliidi) and Monarthropalpus buxi (Cecidomyiidi), which are characterized by the absence of any structure related to the control of motility (that is, the central pair complex, radial spokes and inner dynein arms); however, these sperm are motile, and motility is driven by the outer dynein arms only. This simplification of the motility machinery is accompanied by a parallel reduction in the dynein isoform complement. Here, we complete our survey of the axonemal organization and the parallel evolution of sperm dynein complement in cecidomids with the characterization of both the sperm ultrastructure and the dynein genes in Dryomyia lichtensteini, a representative of Lasiopteridi, the cecidomid taxon with aberrant and immotile sperm cells. On the basis of the whole set of our data, we discuss the potential molecular mechanism(s) underlying the progressive modification of axoneme in cecidomids, leading first to a reduction of dynein genes and eventually to the complete loss of motility.
Topics: Animals; Axoneme; Dyneins; Male; Sperm Motility; Spermatozoa
PubMed: 26940973
DOI: 10.1002/cm.21291 -
Cold Spring Harbor Perspectives in... Aug 2017The cilium is an elongated and continuous structure that spans two major subcellular domains. The cytoplasmic domain contains a short centriole, which serves to nucleate... (Review)
Review
The cilium is an elongated and continuous structure that spans two major subcellular domains. The cytoplasmic domain contains a short centriole, which serves to nucleate the main projection of the cilium. This projection, known as the axoneme, remains separated from the cytoplasm by a specialized gatekeeping complex within a ciliary subdomain called the transition zone. In this way, the axoneme is compartmentalized. Intriguingly, however, this general principle of cilium biology is altered in the sperm cells of many animals, which instead contain a cytoplasmic axoneme domain. Here, we discuss the hypothesis that the formation of specialized sperm giant centrioles and cytoplasmic cilia is mediated by the migration of the transition zone from its typical location as part of a structure known as the annulus and examine the intrinsic properties of the transition zone that may facilitate its migratory behavior.
Topics: Animals; Axoneme; Centrioles; Cilia; Humans
PubMed: 28108487
DOI: 10.1101/cshperspect.a028142 -
Current Opinion in Cell Biology Feb 2010Recently published information on the role of intraflagellar transport (IFT) polypeptides in vesicle exocytosis is reviewed, describing the formation of the immune... (Review)
Review
Recently published information on the role of intraflagellar transport (IFT) polypeptides in vesicle exocytosis is reviewed, describing the formation of the immune synapse in nonciliated cells as an example. A hypothesis is detailed suggesting that all polypeptides which enter the cilium, both membrane and axonemal, do so in association, first, with cytoplasmic vesicles which exocytose adjacent to the ciliary basal body, and then with the ciliary membrane. Axonemal proteins are moved to the ciliary tip by peripheral association with the inner aspects of the ciliary membrane by cannonical ciliary IFT. At the tip, some polypeptides are released for axonemal assembly, and others are budded off as part of vesicular exosomes into the environment. It is proposed that the cilium, in addition to being a sensory and motile organelle, is also a secretory organelle.
Topics: Animals; Axoneme; Biological Transport; Cilia; Cytoplasmic Vesicles; Exocytosis; Flagella; Immunological Synapses; Molecular Motor Proteins
PubMed: 19962875
DOI: 10.1016/j.ceb.2009.10.010 -
Reproduction in Domestic Animals =... Dec 2010It has been shown that DNAJB13, a type II heat shock protein 40, is highly expressed in the testis and is an axonemal component of mouse mature spermatozoa. By...
It has been shown that DNAJB13, a type II heat shock protein 40, is highly expressed in the testis and is an axonemal component of mouse mature spermatozoa. By multi-tissue reverse transcription polymerase chain reaction, we found that Dnajb13 gene was expressed not only in the testis but also in several other ciliated cell-containing tissues like brain, lung and oviduct. Immunohistochemistry on mouse trachea and oviduct sections shown that DNAJB13 was present in the motile cilia of those tissues. To define further its localization in the axoneme, immunoelectron microscopy of mouse sperm flagella was performed and shown that DNAJB13 was localized to radial spokes of the axoneme. Taken together, our data indicate that DNAJB13 is a radial spoke protein of the mouse '9+2' axoneme.
Topics: Animals; Apoptosis Regulatory Proteins; Axoneme; Female; Gene Expression Regulation; HSP40 Heat-Shock Proteins; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Microscopy, Immunoelectron; Molecular Chaperones; Protein Transport
PubMed: 19919626
DOI: 10.1111/j.1439-0531.2009.01473.x -
Proceedings of the National Academy of... May 2019We report a complete 3D structural model of typical epithelial primary cilia based on structural maps of full-length primary cilia obtained by serial section electron...
We report a complete 3D structural model of typical epithelial primary cilia based on structural maps of full-length primary cilia obtained by serial section electron tomography. Our data demonstrate the architecture of primary cilia differs extensively from the commonly acknowledged 9+0 paradigm. The axoneme structure is relatively stable but gradually evolves from base to tip with a decreasing number of microtubule complexes (MtCs) and a reducing diameter. The axonemal MtCs are cross-linked by previously unrecognized fibrous protein networks. Such an architecture explains why primary cilia can elastically withstand liquid flow for mechanosensing. The nine axonemal MtCs in a cilium are found to differ significantly in length indicating intraflagellar transport processes in primary cilia may be more complicated than that reported for motile cilia. The 3D maps of microtubule doublet-singlet transitions generally display longitudinal gaps at the inner junction between the A- and B-tubules, which indicates the inner junction protein is a major player in doublet-singlet transitions. In addition, vesicles releasing from kidney primary cilia were observed in the structural maps, supporting that ciliary vesicles budding may serve as ectosomes for cell-cell communication.
Topics: Animals; Axoneme; Cell Line; Cilia; Cytoplasmic Vesicles; Dogs; Electron Microscope Tomography; Epithelial Cells; Imaging, Three-Dimensional; Microtubules
PubMed: 31004057
DOI: 10.1073/pnas.1821064116