scholarly journals The conserved centrosomal protein FOR20 is required for assembly of the transition zone and basal body docking at the cell surface

2012 ◽  
Vol 125 (18) ◽  
pp. 4395-4404 ◽  
Author(s):  
A. Aubusson-Fleury ◽  
M. Lemullois ◽  
N. G. de Loubresse ◽  
C. Laligne ◽  
J. Cohen ◽  
...  
Keyword(s):  
Cell Surface ◽  
Transition Zone ◽  
Basal Body ◽  
Centrosomal Protein

The ultrastructure of the somatic cortex of Pseudomicrothorax dubius: structure and function of the epiplasm in ciliated protozoa

1977 ◽  
Vol 25 (1) ◽  
pp. 367-385
Author(s):  
R.K. Peck
Keyword(s):  
Cell Surface ◽  
Basal Body ◽  
Structure And Function ◽  
Basal Bodies ◽  
Ciliated Protozoa ◽  
Somatic Cortex ◽  
And Function

The ultrastructure of the somatic cortex of the ciliate Pseudomicrothorax dubius is studied with emphasis on the epiplasm layer which lies immediately under the inner alveolar membrane and is continuous with the terminal plates of cortical basal bodies. In addition to a clearly demonstrable cytoskeletal role, the epiplasm appears to function as a comenting substance which integrates numerous cortical fibres and membranes. The kinetodesmal, postciliary and transverse fibre systems which originate at the proximal ends of basal bodies extend toward the cell surface and end at or in the epiplasm. Inner alveolar membranes and trichocyst membranes are attached to the epiplasm. Basal bodies are anchored into the epiplasm via their terminal plates. The epiplasm appears to be morphogenetically important as a matrix into which newly formed basal bodies insert. Electron-opaque arms occur at the terminal plate level of new basal bodies, and these arms fuse with the epiplasm when basal body insertion occurs. The position of trichocysts in the cortex is specified by the epiplasm. Evidence from numerous other ciliates tends to confirm both structural and morphogenetic roles of the epiplasm.

scholarly journals THE RELATIONSHIP BETWEEN THE FINE STRUCTURE AND DIRECTION OF BEAT IN GILL CILIA OF A LAMELLIBRANCH MOLLUSC

1961 ◽  
Vol 11 (1) ◽  
pp. 179-205 ◽  
Author(s):  
I. R. Gibbons
Keyword(s):  
Fine Structure ◽  
Cell Surface ◽  
Basal Body ◽  
Transitional Region ◽  
Basal Bodies ◽  
Conical Structure ◽  
The Relationship ◽  
Basal Foot ◽  
Different Levels ◽  
Outer Fiber

This paper describes the fine structure and its relationship to the direction of beat in four types of cilia on the gill of the fresh-water mussel Anodonta cataracta. The cilia contain nine outer, nine secondary, and two central fibers, such as have been described previously in other material. Each outer fiber is a doublet with one subfiber bearing arms. One particular pair of outer fibers (numbers 5 and 6) are joined together by a bridge. The two central fibers are enclosed by a central sheath; also present in this region is a single, small mid-fiber. The different groups of fibers are connected together by radial links that extend from the outer to the secondary fibers, and from the secondary fibers to the central sheath. The basal body consists of a cylinder of nine triplet fibers. Projecting from it on one side is a dense conical structure called the basal foot. The cylinder of outer fibers continues from the basal body into the cilium, passing through a complex transitional region in which five distinct changes of structure occur at different levels. There are two sets of fibers associated with the basal bodies: a pair of striated rootlets that extends from each basal body down into the cell, and a system of fine tubular fibers that runs parallel to the cell surface. The relationship between fine structure and direction of beat is the same in all four types of cilia examined. The plane of beat is perpendicular to the plane of the central fibers, with the effective stroke toward the bridge between outer fibers 5 and 6, and toward the foot on the basal body.

scholarly journals DEVELOPMENT OF THE FLAGELLAR APPARATUS OF NAEGLERIA

1966 ◽  
Vol 31 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Allan D. Dingle ◽  
Chandler Fulton
Keyword(s):  
Cell Membrane ◽  
Cell Surface ◽  
Basal Body ◽  
Flagellar Apparatus ◽  
Basal Bodies ◽  
Naegleria Gruberi

Flagellates of Naegleria gruberi have an interconnected flagellar apparatus consisting of nucleus, rhizoplast and accessory filaments, basal bodies, and flagella. The structures of these components have been found to be similar to those in other flagellates. The development of methods for obtaining the relatively synchronous transformation of populations of Naegleria amebae into flagellates has permitted a study of the development of the flagellar apparatus. No indications of rhizoplast, basal body, or flagellum structures could be detected in amebae. A basal body appears and assumes a position at the cell surface with its filaments perpendicular to the cell membrane. Axoneme filaments extend from the basal body filaments into a progressive evagination of the cell membrane which becomes the flagellum sheath. Continued elongation of the axoneme filaments leads to differentiation of a fully formed flagellum with a typical "9 + 2" organization, within 10 min after the appearance of basal bodies.

scholarly journals The ternary complex CEP90, FOPNL and OFD1 specifies the future location of centriolar distal appendages, and promotes their assembly

2021 ◽  
Author(s):  
Pierrick Le Borgne ◽  
Marine Hélène Laporte ◽  
Logan Greibill ◽  
Michel Lemullois ◽  
Mebarek Temagoult ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Plasma Membrane ◽  
Transition Zone ◽  
Basal Body ◽  
Mammalian Cells ◽  
Ternary Complex ◽  
Basal Bodies ◽  
Sequence Of Events ◽  
The Future ◽  
High Conservation

Cilia assembly starts with centriole to basal body maturation, migration to the cell surface and docking to the plasma membrane. The basal body docking process involves the interaction of both the distal end of the basal body and the transition fibers (or mature distal appendages), with the plasma membrane. During this process, the transition zone assembles and forms the structural junction between the basal body and the nascent cilium. Mutations in numerous genes involved in basal body docking and transition zone assembly are associated with the most severe ciliopathies, highlighting the importance of these events in cilium biogenesis. The conservation of this sequence of events across phyla is paralleled by a high conservation of the proteins involved. We identified CEP90 by BioID using FOPNL as a bait. Ultrastructure expansion microscopy showed that CEP90, FOPNL and OFD1 localized at the distal end of both centrioles/basal bodies in Paramecium and mammalian cells. These proteins are recruited early after duplication on the procentriole. Finally, functional analysis performed both in Paramecium and mammalian cells demonstrate the requirement of this complex for distal appendage assembly and basal body docking. Altogether, we propose that this ternary complex is required to determine the future position of distal appendages

scholarly journals Proteins that control the geometry of microtubules at the ends of cilia

2018 ◽  
Vol 217 (12) ◽  
pp. 4298-4313 ◽  
Author(s):  
Panagiota Louka ◽  
Krishna Kumar Vasudevan ◽  
Mayukh Guha ◽  
Ewa Joachimiak ◽  
Dorota Wloga ◽  
...  
Keyword(s):  
Transition Zone ◽  
Basal Body ◽  
Distal Segment ◽  
Joubert Syndrome ◽  
Nanometer Scale ◽  
Negative Regulators ◽  
Middle Segment ◽  
Sensory Activities

Cilia, essential motile and sensory organelles, have several compartments: the basal body, transition zone, and the middle and distal axoneme segments. The distal segment accommodates key functions, including cilium assembly and sensory activities. While the middle segment contains doublet microtubules (incomplete B-tubules fused to complete A-tubules), the distal segment contains only A-tubule extensions, and its existence requires coordination of microtubule length at the nanometer scale. We show that three conserved proteins, two of which are mutated in the ciliopathy Joubert syndrome, determine the geometry of the distal segment, by controlling the positions of specific microtubule ends. FAP256/CEP104 promotes A-tubule elongation. CHE-12/Crescerin and ARMC9 act as positive and negative regulators of B-tubule length, respectively. We show that defects in the distal segment dimensions are associated with motile and sensory deficiencies of cilia. Our observations suggest that abnormalities in distal segment organization cause a subset of Joubert syndrome cases.

Role of DZIP1–CBY–FAM92 transition zone complex in the basal body to membrane attachment and ciliary budding

2020 ◽  
Vol 48 (3) ◽  
pp. 1067-1075
Author(s):  
Jean-André Lapart ◽  
Amélie Billon ◽  
Jean-Luc Duteyrat ◽  
Joëlle Thomas ◽  
Bénédicte Durand
Keyword(s):  
Transition Zone ◽  
Basal Body ◽  
Cell Types ◽  
Molecular Assembly ◽  
Bud Formation ◽  
Wide Range ◽  
Membrane Attachment ◽  
Functional Hierarchy ◽  
Complex Architecture ◽  
Different Cell Types

Cilia play important signaling or motile functions in various organisms. In Human, cilia dysfunctions are responsible for a wide range of diseases, called ciliopathies. Cilia assembly is a tightly controlled process, which starts with the conversion of the centriole into a basal body, leading to the formation of the ciliary bud that protrudes inside a ciliary vesicle and/or ultimately at the cell surface. Ciliary bud formation is associated with the assembly of the transition zone (TZ), a complex architecture of proteins of the ciliary base which plays critical functions in gating proteins in and out of the ciliary compartment. Many proteins are involved in the assembly of the TZ, which shows structural and functional variations in different cell types or organisms. In this review, we discuss how a particular complex, composed of members of the DZIP1, CBY and FAM92 families of proteins, is required for the initial stages of cilia assembly leading to ciliary bud formation and how their functional hierarchy contributes to TZ assembly. Moreover, we summarize how evidences in Drosophila reveal functional differences of the DZIP1–CBY–FAM92 complex in the different ciliated tissues of this organism. Whereas it is essential for proper TZ assembly in the two types of ciliated tissues, it is involved in stable anchoring of basal bodies to the plasma membrane in male germ cells. Overall, the DZIP1–CBY–FAM92 complex reveals a molecular assembly pathway required for the initial stages of ciliary bud formation and that is conserved from Drosophila to Human.

scholarly journals MKS and NPHP modules cooperate to establish basal body/transition zone membrane associations and ciliary gate function during ciliogenesis

2011 ◽  
Vol 192 (6) ◽  
pp. 1023-1041 ◽  
Author(s):  
Corey L. Williams ◽  
Chunmei Li ◽  
Katarzyna Kida ◽  
Peter N. Inglis ◽  
Swetha Mohan ◽  
...  
Keyword(s):  
Transition Zone ◽  
Basal Body ◽  
Intraflagellar Transport ◽  
C Elegans ◽  
Disease Spectrum ◽  
Phenotypic Features ◽  
Surrounding Membrane

Meckel-Gruber syndrome (MKS), nephronophthisis (NPHP), and related ciliopathies present with overlapping phenotypes and display considerable allelism between at least twelve different genes of largely unexplained function. We demonstrate that the conserved C. elegans B9 domain (MKS-1, MKSR-1, and MKSR-2), MKS-3/TMEM67, MKS-5/RPGRIP1L, MKS-6/CC2D2A, NPHP-1, and NPHP-4 proteins exhibit essential, collective functions at the transition zone (TZ), an underappreciated region at the base of all cilia characterized by Y-shaped assemblages that link axoneme microtubules to surrounding membrane. These TZ proteins functionally interact as members of two distinct modules, which together contribute to an early ciliogenic event. Specifically, MKS/MKSR/NPHP proteins establish basal body/TZ membrane attachments before or coinciding with intraflagellar transport–dependent axoneme extension and subsequently restrict accumulation of nonciliary components within the ciliary compartment. Together, our findings uncover a unified role for eight TZ-localized proteins in basal body anchoring and establishing a ciliary gate during ciliogenesis, and suggest that disrupting ciliary gate function contributes to phenotypic features of the MKS/NPHP disease spectrum.

scholarly journals An analogue-sensitive approach identifies basal body rotation and flagellum attachment zone elongation as key functions of PLK in Trypanosoma brucei

2013 ◽  
Vol 24 (9) ◽  
pp. 1321-1333 ◽  
Author(s):  
Ana Lozano-Núñez ◽  
Kyojiro N. Ikeda ◽  
Thomas Sauer ◽  
Christopher L. de Graffenried
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Rna Interference ◽  
Cell Surface ◽  
Trypanosoma Brucei ◽  
Basal Body ◽  
Basal Bodies ◽  
Body Rotation ◽  
The Many ◽  
Attachment Zone

Polo-like kinases are important regulators of cell division, playing diverse roles in mitosis and cytoskeletal inheritance. In the parasite Trypanosoma brucei, the single PLK homologue TbPLK is necessary for the assembly of a series of essential organelles that position and adhere the flagellum to the cell surface. Previous work relied on RNA interference or inhibitors of undefined specificity to inhibit TbPLK, both of which have significant experimental limitations. Here we use an analogue-sensitive approach to selectively and acutely inhibit TbPLK. T. brucei cells expressing only analogue-sensitive TbPLK (TbPLKas) grow normally, but upon treatment with inhibitor develop defects in flagellar attachment and cytokinesis. TbPLK cannot migrate effectively when inhibited and remains trapped in the posterior of the cell throughout the cell cycle. Using synchronized cells, we show that active TbPLK is a direct requirement for the assembly and extension of the flagellum attachment zone, which adheres the flagellum to the cell surface, and for the rotation of the duplicated basal bodies, which positions the new flagellum so that it can extend without impinging on the old flagellum. This approach should be applicable to the many kinases found in the T. brucei genome that lack an ascribed function.

scholarly journals Rpgrip1l controls ciliary gating by ensuring the proper amount of Cep290 at the vertebrate transition zone

2020 ◽  
Author(s):  
Antonia Wiegering ◽  
Renate Dildrop ◽  
Christine Vesque ◽  
Sylvie Schneider-Maunoury ◽  
Christoph Gerhardt
Keyword(s):  
Transition Zone ◽  
Basal Body ◽  
Primary Cilia ◽  
Human Diseases ◽  
Entry And Exit ◽  
Ciliary Protein ◽  
Genes Encoding ◽  
Mother Centriole ◽  
Protein Entry

AbstractA range of severe human diseases called ciliopathies are caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localise to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.

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