1
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Junker AD, Woodhams LG, Soh AWJ, O’Toole ET, Bayly PV, Pearson CG. Basal bodies bend in response to ciliary forces. Mol Biol Cell 2022; 33:ar146. [PMID: 36287828 PMCID: PMC9727800 DOI: 10.1091/mbc.e22-10-0468-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Motile cilia beat with an asymmetric waveform consisting of a power stroke that generates a propulsive force and a recovery stroke that returns the cilium back to the start. Cilia are anchored to the cell cortex by basal bodies (BBs) that are directly coupled to the ciliary doublet microtubules (MTs). We find that, consistent with ciliary forces imposing on BBs, bending patterns in BB triplet MTs are responsive to ciliary beating. BB bending varies as environmental conditions change the ciliary waveform. Bending occurs where striated fibers (SFs) attach to BBs and mutants with short SFs that fail to connect to adjacent BBs exhibit abnormal BB bending, supporting a model in which SFs couple ciliary forces between BBs. Finally, loss of the BB stability protein Poc1, which helps interconnect BB triplet MTs, prevents the normal distributed BB and ciliary bending patterns. Collectively, BBs experience ciliary forces and manage mechanical coupling of these forces to their surrounding cellular architecture for normal ciliary beating.
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Affiliation(s)
- Anthony D. Junker
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Louis G. Woodhams
- Department of Mechanical Engineering and Material Science, Washington University in St. Louis, St. Louis, MO 63130
| | - Adam W. J. Soh
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Eileen T. O’Toole
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80302
| | - Philip V. Bayly
- Department of Mechanical Engineering and Material Science, Washington University in St. Louis, St. Louis, MO 63130
| | - Chad G. Pearson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,*Address correspondence to: Chad G. Pearson ()
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2
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Soh AWJ, Woodhams LG, Junker AD, Enloe CM, Noren BE, Harned A, Westlake CJ, Narayan K, Oakey JS, Bayly PV, Pearson CG. Intracellular connections between basal bodies promote the coordinated behavior of motile cilia. Mol Biol Cell 2022; 33:br18. [PMID: 35767367 DOI: 10.1091/mbc.e22-05-0150] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Hydrodynamic flow produced by multiciliated cells is critical for fluid circulation and cell motility. Hundreds of cilia beat with metachronal synchrony for fluid flow. Cilia-driven fluid flow produces extracellular hydrodynamic forces that cause neighboring cilia to beat in a synchronized manner. However, hydrodynamic coupling between neighboring cilia is not the sole mechanism that drives cilia synchrony. Cilia are nucleated by basal bodies (BBs) that link to each other and to the cell's cortex via BB-associated appendages. The intracellular BB and cortical network is hypothesized to synchronize ciliary beating by transmitting cilia coordination cues. The extent of intracellular ciliary connections and the nature of these stimuli remain unclear. Moreover, how BB connections influence the dynamics of individual cilia has not been established. We show by focused ion beam scanning electron microscopy imaging that cilia are coupled both longitudinally and laterally in the ciliate Tetrahymena thermophila by the underlying BB and cortical cytoskeletal network. To visualize the behavior of individual cilia in live, immobilized Tetrahymena cells, we developed Delivered Iron Particle Ubiety Live Light (DIPULL) microscopy. Quantitative and computer analyses of ciliary dynamics reveal that BB connections control ciliary waveform and coordinate ciliary beating. Loss of BB connections reduces cilia-dependent fluid flow forces.
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Affiliation(s)
- Adam W J Soh
- Department of Cell and Developmental Biology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045
| | - Louis G Woodhams
- Department of Mechanical Engineering and Material Science, Washington University in St. Louis, St. Louis, MO 63130
| | - Anthony D Junker
- Department of Cell and Developmental Biology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045
| | - Cassidy M Enloe
- Department of Chemical Engineering, College of Engineering and Applied Science, University of Wyoming, Laramie, WY 82071
| | - Benjamin E Noren
- Department of Chemical Engineering, College of Engineering and Applied Science, University of Wyoming, Laramie, WY 82071
| | - Adam Harned
- Center for Molecular Microscopy and Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.,Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, and
| | - Christopher J Westlake
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Kedar Narayan
- Center for Molecular Microscopy and Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.,Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, and
| | - John S Oakey
- Department of Chemical Engineering, College of Engineering and Applied Science, University of Wyoming, Laramie, WY 82071
| | - Philip V Bayly
- Department of Mechanical Engineering and Material Science, Washington University in St. Louis, St. Louis, MO 63130
| | - Chad G Pearson
- Department of Cell and Developmental Biology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045
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3
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Soh AWJ, van Dam TJP, Stemm-Wolf AJ, Pham AT, Morgan GP, O'Toole ET, Pearson CG. Ciliary force-responsive striated fibers promote basal body connections and cortical interactions. J Cell Biol 2020; 219:jcb.201904091. [PMID: 31740506 PMCID: PMC7039215 DOI: 10.1083/jcb.201904091] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/15/2019] [Accepted: 10/02/2019] [Indexed: 12/28/2022] Open
Abstract
Multi-ciliary arrays promote fluid flow and cellular motility using the polarized and coordinated beating of hundreds of motile cilia. Tetrahymena basal bodies (BBs) nucleate and position cilia, whereby BB-associated striated fibers (SFs) promote BB anchorage and orientation into ciliary rows. Mutants that shorten SFs cause disoriented BBs. In contrast to the cytotaxis model, we show that disoriented BBs with short SFs can regain normal orientation if SF length is restored. In addition, SFs adopt unique lengths by their shrinkage and growth to establish and maintain BB connections and cortical interactions in a ciliary force-dependent mechanism. Tetrahymena SFs comprise at least eight uniquely localizing proteins belonging to the SF-assemblin family. Loss of different proteins that localize to the SF base disrupts either SF steady-state length or ciliary force-induced SF elongation. Thus, the dynamic regulation of SFs promotes BB connections and cortical interactions to organize ciliary arrays.
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Affiliation(s)
- Adam W J Soh
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
| | - Teunis J P van Dam
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, Netherlands
| | - Alexander J Stemm-Wolf
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
| | - Andrew T Pham
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
| | - Garry P Morgan
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO
| | - Eileen T O'Toole
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO
| | - Chad G Pearson
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
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4
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Heydeck W, Bayless BA, Stemm-Wolf AJ, O'Toole ET, Fabritius AS, Ozzello C, Nguyen M, Winey M. Tetrahymena Poc5 is a transient basal body component that is important for basal body maturation. J Cell Sci 2020; 133:jcs.240838. [PMID: 32350068 DOI: 10.1242/jcs.240838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 04/06/2020] [Indexed: 01/26/2023] Open
Abstract
Basal bodies (BBs) are microtubule-based organelles that act as a template for and stabilize cilia at the cell surface. Centrins ubiquitously associate with BBs and function in BB assembly, maturation and stability. Human POC5 (hPOC5) is a highly conserved centrin-binding protein that binds centrins through Sfi1p-like repeats and is required for building full-length, mature centrioles. Here, we use the BB-rich cytoskeleton of Tetrahymena thermophila to characterize Poc5 BB functions. Tetrahymena Poc5 (TtPoc5) uniquely incorporates into assembling BBs and is then removed from mature BBs prior to ciliogenesis. Complete genomic knockout of TtPOC5 leads to a significantly increased production of BBs, yet a markedly reduced ciliary density, both of which are rescued by reintroduction of TtPoc5. A second Tetrahymena POC5-like gene, SFR1, is similarly implicated in modulating BB production. When TtPOC5 and SFR1 are co-deleted, cell viability is compromised and BB overproduction is exacerbated. Overproduced BBs display defective transition zone formation and a diminished capacity for ciliogenesis. This study uncovers a requirement for Poc5 in building mature BBs, providing a possible functional link between hPOC5 mutations and impaired cilia.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Westley Heydeck
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Brian A Bayless
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Alexander J Stemm-Wolf
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eileen T O'Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Courtney Ozzello
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Marina Nguyen
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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5
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Junker AD, Soh AWJ, O'Toole ET, Meehl JB, Guha M, Winey M, Honts JE, Gaertig J, Pearson CG. Microtubule glycylation promotes attachment of basal bodies to the cell cortex. J Cell Sci 2019; 132:jcs.233726. [PMID: 31243050 DOI: 10.1242/jcs.233726] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 06/18/2019] [Indexed: 12/13/2022] Open
Abstract
Motile cilia generate directed hydrodynamic flow that is important for the motility of cells and extracellular fluids. To optimize directed hydrodynamic flow, motile cilia are organized and oriented into a polarized array. Basal bodies (BBs) nucleate and position motile cilia at the cell cortex. Cytoplasmic BB-associated microtubules are conserved structures that extend from BBs. By using the ciliate, Tetrahymena thermophila, combined with EM-tomography and light microscopy, we show that BB-appendage microtubules assemble coincidently with new BB assembly and that they are attached to the cell cortex. These BB-appendage microtubules are specifically marked by post translational modifications of tubulin, including glycylation. Mutations that prevent glycylation shorten BB-appendage microtubules and disrupt BB positioning and cortical attachment. Consistent with the attachment of BB-appendage microtubules to the cell cortex to position BBs, mutations that disrupt the cellular cortical cytoskeleton disrupt the cortical attachment and positioning of BBs. In summary, BB-appendage microtubules promote the organization of ciliary arrays through attachment to the cell cortex.
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Affiliation(s)
- Anthony D Junker
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Adam W J Soh
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eileen T O'Toole
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80302, USA
| | - Janet B Meehl
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80302, USA
| | - Mayukh Guha
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Jerry E Honts
- Department of Biology, Drake University, 2507 University Avenue, Des Moines, IA 50311, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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6
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Tolsma TO, Cuevas LM, Di Pietro SM. The Sla1 adaptor-clathrin interaction regulates coat formation and progression of endocytosis. Traffic 2018. [PMID: 29542219 DOI: 10.1111/tra.12563] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Clathrin-mediated endocytosis is a fundamental transport pathway that depends on numerous protein-protein interactions. Testing the importance of the adaptor protein-clathrin interaction for coat formation and progression of endocytosis in vivo has been difficult due to experimental constrains. Here, we addressed this question using the yeast clathrin adaptor Sla1, which is unique in showing a cargo endocytosis defect upon substitution of 3 amino acids in its clathrin-binding motif (sla1AAA ) that disrupt clathrin binding. Live-cell imaging showed an impaired Sla1-clathrin interaction causes reduced clathrin levels but increased Sla1 levels at endocytic sites. Moreover, the rate of Sla1 recruitment was reduced indicating proper dynamics of both clathrin and Sla1 depend on their interaction. sla1AAA cells showed a delay in progression through the various stages of endocytosis. The Arp2/3-dependent actin polymerization machinery was present for significantly longer time before actin polymerization ensued, revealing a link between coat formation and activation of actin polymerization. Ultimately, in sla1AAA cells a larger than normal actin network was formed, dramatically higher levels of various machinery proteins other than clathrin were recruited, and the membrane profile of endocytic invaginations was longer. Thus, the Sla1-clathrin interaction is important for coat formation, regulation of endocytic progression and membrane bending.
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Affiliation(s)
- Thomas O Tolsma
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado
| | - Lena M Cuevas
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado
| | - Santiago M Di Pietro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado
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7
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Sfr1, a Tetrahymena thermophila Sfi1 Repeat Protein, Modulates the Production of Cortical Row Basal Bodies. mSphere 2016; 1:mSphere00257-16. [PMID: 27904881 PMCID: PMC5112337 DOI: 10.1128/msphere.00257-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/14/2016] [Indexed: 01/08/2023] Open
Abstract
Basal bodies and centrioles are structurally similar and, when rendered dysfunctional as a result of improper assembly or maintenance, are associated with human diseases. Centrins are conserved and abundant components of both structures whose basal body and centriolar functions remain incompletely understood. Despite the extensive study of centrins in Tetrahymena thermophila, little is known about how centrin-binding proteins contribute to centrin’s roles in basal body assembly, stability, and orientation. The sole previous study of the large centrin-binding protein family in Tetrahymena revealed a role for Sfr13 in the stabilization and separation of basal bodies. In this study, we found that Sfr1 localizes to all Tetrahymena basal bodies and complete genetic deletion of SFR1 leads to overproduction of basal bodies. The uncovered inhibitory role of Sfr1 in basal body production suggests that centrin-binding proteins, as well as centrins, may influence basal body number both positively and negatively. Basal bodies are essential microtubule-based structures that template, anchor, and orient cilia at the cell surface. Cilia act primarily in the generation of directional fluid flow and sensory reception, both of which are utilized for a broad spectrum of cellular processes. Although basal bodies contribute to vital cell functions, the molecular contributors of their assembly and maintenance are poorly understood. Previous studies of the ciliate Tetrahymena thermophila revealed important roles for two centrin family members in basal body assembly, separation of new basal bodies, and stability. Here, we characterize the basal body function of a centrin-binding protein, Sfr1, in Tetrahymena. Sfr1 is part of a large family of 13 proteins in Tetrahymena that contain Sfi1 repeats (SFRs), a motif originally identified in Saccharomyces cerevisiae Sfi1 that binds centrin. Sfr1 is the only SFR protein in Tetrahymena that localizes to all cortical row and oral apparatus basal bodies. In addition, Sfr1 resides predominantly at the microtubule scaffold from the proximal cartwheel to the distal transition zone. Complete genomic knockout of SFR1 (sfr1Δ) causes a significant increase in both cortical row basal body density and the number of cortical rows, contributing to an overall overproduction of basal bodies. Reintroduction of Sfr1 into sfr1Δ mutant cells leads to a marked reduction of cortical row basal body density and the total number of cortical row basal bodies. Therefore, Sfr1 directly modulates cortical row basal body production. This study reveals an inhibitory role for Sfr1, and potentially centrins, in Tetrahymena basal body production. IMPORTANCE Basal bodies and centrioles are structurally similar and, when rendered dysfunctional as a result of improper assembly or maintenance, are associated with human diseases. Centrins are conserved and abundant components of both structures whose basal body and centriolar functions remain incompletely understood. Despite the extensive study of centrins in Tetrahymena thermophila, little is known about how centrin-binding proteins contribute to centrin’s roles in basal body assembly, stability, and orientation. The sole previous study of the large centrin-binding protein family in Tetrahymena revealed a role for Sfr13 in the stabilization and separation of basal bodies. In this study, we found that Sfr1 localizes to all Tetrahymena basal bodies and complete genetic deletion of SFR1 leads to overproduction of basal bodies. The uncovered inhibitory role of Sfr1 in basal body production suggests that centrin-binding proteins, as well as centrins, may influence basal body number both positively and negatively.
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8
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Bayless BA, Galati DF, Junker AD, Backer CB, Gaertig J, Pearson CG. Asymmetrically localized proteins stabilize basal bodies against ciliary beating forces. J Cell Biol 2016; 215:457-466. [PMID: 27807131 PMCID: PMC5119938 DOI: 10.1083/jcb.201604135] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/24/2016] [Accepted: 10/04/2016] [Indexed: 11/26/2022] Open
Abstract
Basal bodies (BBs) organize and anchor motile cilia. This study uncovers components that asymmetrically localize to the rotationally symmetric BBs, where they fortify specific BB domains. Asymmetrically localized BB components are necessary to resist asymmetric ciliary forces. Basal bodies are radially symmetric, microtubule-rich structures that nucleate and anchor motile cilia. Ciliary beating produces asymmetric mechanical forces that are resisted by basal bodies. To resist these forces, distinct regions within the basal body ultrastructure and the microtubules themselves must be stable. However, the molecular components that stabilize basal bodies remain poorly defined. Here, we determine that Fop1 functionally interacts with the established basal body stability components Bld10 and Poc1. We find that Fop1 and microtubule glutamylation incorporate into basal bodies at distinct stages of assembly, culminating in their asymmetric enrichment at specific triplet microtubule regions that are predicted to experience the greatest mechanical force from ciliary beating. Both Fop1 and microtubule glutamylation are required to stabilize basal bodies against ciliary beating forces. Our studies reveal that microtubule glutamylation and Bld10, Poc1, and Fop1 stabilize basal bodies against the forces produced by ciliary beating via distinct yet interdependent mechanisms.
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Affiliation(s)
- Brian A Bayless
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Domenico F Galati
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Anthony D Junker
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Chelsea B Backer
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
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9
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Galati DF, Bonney S, Kronenberg Z, Clarissa C, Yandell M, Elde NC, Jerka-Dziadosz M, Giddings TH, Frankel J, Pearson CG. DisAp-dependent striated fiber elongation is required to organize ciliary arrays. ACTA ACUST UNITED AC 2015; 207:705-15. [PMID: 25533842 PMCID: PMC4274257 DOI: 10.1083/jcb.201409123] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
DisAp is a novel kinetodesmal fiber component that is essential for force-dependent fiber elongation and the alignment of basal body orientation in multiciliary arrays. Cilia-organizing basal bodies (BBs) are microtubule scaffolds that are visibly asymmetrical because they have attached auxiliary structures, such as striated fibers. In multiciliated cells, BB orientation aligns to ensure coherent ciliary beating, but the mechanisms that maintain BB orientation are unclear. For the first time in Tetrahymena thermophila, we use comparative whole-genome sequencing to identify the mutation in the BB disorientation mutant disA-1. disA-1 abolishes the localization of the novel protein DisAp to T.thermophila striated fibers (kinetodesmal fibers; KFs), which is consistent with DisAp’s similarity to the striated fiber protein SF-assemblin. We demonstrate that DisAp is required for KFs to elongate and to resist BB disorientation in response to ciliary forces. Newly formed BBs move along KFs as they approach their cortical attachment sites. However, because they contain short KFs that are rotated, BBs in disA-1 cells display aberrant spacing and disorientation. Therefore, DisAp is a novel KF component that is essential for force-dependent KF elongation and BB orientation in multiciliary arrays.
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Affiliation(s)
- Domenico F Galati
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
| | - Stephanie Bonney
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
| | - Zev Kronenberg
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Christina Clarissa
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309
| | - Mark Yandell
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Nels C Elde
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Maria Jerka-Dziadosz
- Department of Cell Biology, M. Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Thomas H Giddings
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309
| | - Joseph Frankel
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242
| | - Chad G Pearson
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
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10
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Bultema JJ, Boyle JA, Malenke PB, Martin FE, Dell'Angelica EC, Cheney RE, Di Pietro SM. Myosin vc interacts with Rab32 and Rab38 proteins and works in the biogenesis and secretion of melanosomes. J Biol Chem 2014; 289:33513-28. [PMID: 25324551 DOI: 10.1074/jbc.m114.578948] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class V myosins are actin-based motors with conserved functions in vesicle and organelle trafficking. Herein we report the discovery of a function for Myosin Vc in melanosome biogenesis as an effector of melanosome-associated Rab GTPases. We isolated Myosin Vc in a yeast two-hybrid screening for proteins that interact with Rab38, a Rab protein involved in the biogenesis of melanosomes and other lysosome-related organelles. Rab38 and its close homolog Rab32 bind to Myosin Vc but not to Myosin Va or Myosin Vb. Binding depends on residues in the switch II region of Rab32 and Rab38 and regions of the Myosin Vc coiled-coil tail domain. Myosin Vc also interacts with Rab7a and Rab8a but not with Rab11, Rab17, and Rab27. Although Myosin Vc is not particularly abundant on pigmented melanosomes, its knockdown in MNT-1 melanocytes caused defects in the trafficking of integral membrane proteins to melanosomes with substantially increased surface expression of Tyrp1, nearly complete loss of Tyrp2, and significant Vamp7 mislocalization. Knockdown of Myosin Vc in MNT-1 cells more than doubled the abundance of pigmented melanosomes but did not change the number of unpigmented melanosomes. Together the data demonstrate a novel role for Myosin Vc in melanosome biogenesis and secretion.
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Affiliation(s)
- Jarred J Bultema
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, the Department of Chemistry and Biochemistry, University of Colorado, Colorado Springs, Colorado Springs, Colorado 80918
| | - Judith A Boyle
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Parker B Malenke
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Faye E Martin
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Esteban C Dell'Angelica
- the Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095, and
| | - Richard E Cheney
- the Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Santiago M Di Pietro
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523,
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11
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Membrane dynamics at the nuclear exchange junction during early mating (one to four hours) in the ciliate Tetrahymena thermophila. EUKARYOTIC CELL 2014; 14:116-27. [PMID: 25107923 DOI: 10.1128/ec.00164-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Using serial-section transmission electron microscopy and three-dimensional (3D) electron tomography, we characterized membrane dynamics that accompany the construction of a nuclear exchange junction between mating cells in the ciliate Tetrahymena thermophila. Our methods revealed a number of previously unknown features. (i) Membrane fusion is initiated by the extension of hundreds of 50-nm-diameter protrusions from the plasma membrane. These protrusions extend from both mating cells across the intercellular space to fuse with membrane of the mating partner. (ii) During this process, small membrane-bound vesicles or tubules are shed from the plasma membrane and into the extracellular space within the junction. The resultant vesicle-filled pockets within the extracellular space are referred to as junction lumens. (iii) As junction lumens fill with extracellular microvesicles and swell, the plasma membrane limiting these swellings undergoes another deformation, pinching off vesicle-filled vacuoles into the cytoplasm (reclamation). (iv) These structures (resembling multivesicular bodies) seem to associate with autophagosomes abundant near the exchange junction. We propose a model characterizing the membrane-remodeling events that establish cytoplasmic continuity between mating Tetrahymena cells. We also discuss the possible role of nonvesicular lipid transport in conditioning the exchange junction lipid environment. Finally, we raise the possibility of an intercellular signaling mechanism involving microvesicle shedding and uptake.
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12
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Karahara I, Kang BH. High-pressure freezing and low-temperature processing of plant tissue samples for electron microscopy. Methods Mol Biol 2014; 1080:147-57. [PMID: 24132426 DOI: 10.1007/978-1-62703-643-6_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Use of electron tomography methods improves image resolution of transmission electron microscopy especially in the z-direction, enabling determination of complicated 3D structures of organelles and cytoskeleton arrays. The increase in resolution necessitates preservation of cellular structures close to the native states with minimum artifacts. High-pressure freezing (HPF) that immobilizes molecules in the cell instantaneously has been used to avoid damages caused by convention chemical fixation. Despite the advantages of HPF, cells could still be damaged during dissection prior to HPF. Therefore, it is critical to isolate cells/tissues of interest quickly and carefully. The samples frozen by HPF are often processed by freeze substitution (FS), and FS should be carried out under appropriate conditions. Here we describe dissection, HPF, and FS methods that we have utilized to prepare plant samples for electron tomography/immuno-electron microscopy.
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Affiliation(s)
- Ichirou Karahara
- Department of Biology, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan
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13
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Ross I, Clarissa C, Giddings TH, Winey M. ε-tubulin is essential in Tetrahymena thermophila for the assembly and stability of basal bodies. J Cell Sci 2013; 126:3441-51. [PMID: 23704354 DOI: 10.1242/jcs.128694] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Basal bodies and centrioles are conserved microtubule-based organelles the improper assembly of which leads to a number of diseases, including ciliopathies and cancer. Tubulin family members are conserved components of these structures that are integral to their proper formation and function. We have identified the ε-tubulin gene in Tetrahymena thermophila and detected the protein, through fluorescence of a tagged allele, to basal bodies. Immunoelectron microscopy has shown that ε-tubulin localizes primarily to the core microtubule scaffold. A complete genomic knockout of ε-tubulin has revealed that it is an essential gene required for the assembly and maintenance of the triplet microtubule blades of basal bodies. We have conducted site-directed mutagenesis of the ε-tubulin gene and shown that residues within the nucleotide-binding domain, longitudinal interacting domains, and C-terminal tail are required for proper function. A single amino acid change of Thr150, a conserved residue in the nucleotide-binding domain, to Val is a conditional mutation that results in defects in the spatial and temporal assembly of basal bodies as well as their stability. We have genetically separated functions for the domains of ε-tubulin and identified a novel role for the nucleotide-binding domain in the regulation of basal body assembly and stability.
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Affiliation(s)
- Ian Ross
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309, USA
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14
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Stemm-Wolf AJ, Meehl JB, Winey M. Sfr13, a member of a large family of asymmetrically localized Sfi1-repeat proteins, is important for basal body separation and stability in Tetrahymena thermophila. J Cell Sci 2013; 126:1659-71. [PMID: 23426847 DOI: 10.1242/jcs.120238] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Directed fluid flow, which is achieved by the coordinated beating of motile cilia, is required for processes as diverse as cellular swimming, developmental patterning and mucus clearance. Cilia are nucleated, anchored and aligned at the plasma membrane by basal bodies, which are cylindrical microtubule-based structures with ninefold radial symmetry. In the unicellular ciliate Tetrahymena thermophila, two centrin family members associated with the basal body are important for both basal body organization and stabilization. We have identified a family of 13 proteins in Tetrahymena that contain centrin-binding repeats related to those identified in the Saccharomyces cerevisiae Sfi1 protein. We have named these proteins Sfr1-Sfr13 (for Sfi1-repeat). Nine of the Sfr proteins localize in unique polarized patterns surrounding the basal body, suggesting non-identical roles in basal body organization and association with basal body accessory structures. Furthermore, the Sfr proteins are found in distinct basal body populations in Tetrahymena cells, indicating that they are responsive to particular developmental programs. A complete genetic deletion of one of the family members, Sfr13, causes unstable basal bodies and defects in daughter basal body separation from the mother, phenotypes also observed with centrin disruption. It is likely that the other Sfr family members are involved in distinct centrin functions, providing specificity to the tasks that centrins perform at basal bodies.
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Affiliation(s)
- Alexander J Stemm-Wolf
- Department of Molecular, Cellular and Developmental Biology, University of Colorado - Boulder, Boulder, CO 80309, USA
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15
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Bayless BA, Giddings TH, Winey M, Pearson CG. Bld10/Cep135 stabilizes basal bodies to resist cilia-generated forces. Mol Biol Cell 2012; 23:4820-32. [PMID: 23115304 PMCID: PMC3521689 DOI: 10.1091/mbc.e12-08-0577] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/18/2012] [Accepted: 10/23/2012] [Indexed: 12/03/2022] Open
Abstract
Basal bodies nucleate, anchor, and organize cilia. As the anchor for motile cilia, basal bodies must be resistant to the forces directed toward the cell as a consequence of ciliary beating. The molecules and generalized mechanisms that contribute to the maintenance of basal bodies remain to be discovered. Bld10/Cep135 is a basal body outer cartwheel domain protein that has established roles in the assembly of nascent basal bodies. We find that Bld10 protein first incorporates stably at basal bodies early during new assembly. Bld10 protein continues to accumulate at basal bodies after assembly, and we hypothesize that the full complement of Bld10 is required to stabilize basal bodies. We identify a novel mechanism for Bld10/Cep135 in basal body maintenance so that basal bodies can withstand the forces produced by motile cilia. Bld10 stabilizes basal bodies by promoting the stability of the A- and C-tubules of the basal body triplet microtubules and by properly positioning the triplet microtubule blades. The forces generated by ciliary beating promote basal body disassembly in bld10Δ cells. Thus Bld10/Cep135 acts to maintain the structural integrity of basal bodies against the forces of ciliary beating in addition to its separable role in basal body assembly.
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Affiliation(s)
- Brian A. Bayless
- Department of Cell and Developmental Biology, University of Colorado Denver–Anshutz Medical Campus, Aurora, CO 80045-2537
| | - Thomas H. Giddings
- Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309-0347
| | - Mark Winey
- Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309-0347
| | - Chad G. Pearson
- Department of Cell and Developmental Biology, University of Colorado Denver–Anshutz Medical Campus, Aurora, CO 80045-2537
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16
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Ambrosio AL, Boyle JA, Di Pietro SM. Mechanism of platelet dense granule biogenesis: study of cargo transport and function of Rab32 and Rab38 in a model system. Blood 2012; 120:4072-81. [PMID: 22927249 PMCID: PMC3496959 DOI: 10.1182/blood-2012-04-420745] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/12/2012] [Indexed: 12/21/2022] Open
Abstract
Dense granules are important in platelet aggregation to form a hemostatic plug as evidenced by the increased bleeding time in mice and humans with dense granule deficiency. Dense granules also are targeted by antiplatelet agents because of their role in thrombus formation. Therefore, the molecular understanding of the dense granule and its biogenesis is of vital importance. In this work, we establish a human megakaryocytic cell line (MEG-01) as a model system for the study of dense granule biogenesis using a variety of cell biology and biochemical approaches. Using this model system, we determine the late endocytic origin of these organelles by colocalization of the internalized fluid phase marker dextran with both mepacrine and transmembrane dense granule proteins. By mistargeting of mutant dense granule proteins, we demonstrate that sorting signals recognized by adaptor protein-3 are necessary for normal transport to dense granules. Furthermore, we show that tissue-specific Rab32 and Rab38 are crucial for the fusion of vesicles containing dense granule cargo with the maturing organelle. This work sheds light on the biogenesis of dense granules at the molecular level and opens the possibility of using this powerful model system for the investigation of new components of the biogenesis machinery.
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Affiliation(s)
- Andrea L Ambrosio
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
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17
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Vonderfecht T, Cookson MW, Giddings TH, Clarissa C, Winey M. The two human centrin homologues have similar but distinct functions at Tetrahymena basal bodies. Mol Biol Cell 2012; 23:4766-77. [PMID: 23087207 PMCID: PMC3521684 DOI: 10.1091/mbc.e12-06-0454] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Centrins are a ubiquitous family of small Ca(2+)-binding proteins found at basal bodies that are placed into two groups based on sequence similarity to the human centrins 2 and 3. Analyses of basal body composition in different species suggest that they contain a centrin isoform from each group. We used the ciliate protist Tetrahymena thermophila to gain a better understanding of the functions of the two centrin groups and to determine their potential redundancy. We have previously shown that the Tetrahymena centrin 1 (Cen1), a human centrin 2 homologue, is required for proper basal body function. In this paper, we show that the Tetrahymena centrin 2 (Cen2), a human centrin 3 homologue, has functions similar to Cen1 in basal body orientation, maintenance, and separation. The two are, however, not redundant. A further examination of human centrin 3 homologues shows that they function in a manner distinct from human centrin 2 homologues. Our data suggest that basal bodies require a centrin from both groups in order to function correctly.
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Affiliation(s)
- Tyson Vonderfecht
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309, USA
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18
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Fisch C, Dupuis-Williams P. [The rebirth of the ultrastructure of cilia and flagella]. Biol Aujourdhui 2012; 205:245-67. [PMID: 22251859 DOI: 10.1051/jbio/2011023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Indexed: 11/14/2022]
Abstract
The sensory and motility functions of eukaryotic cilia and flagella are essential for cell survival in protozoans and for cell differentiation and homoeostasis in metazoans. Ciliary biology has benefited early on from the input of electron microscopy. Over the last decade, the visualization of cellular structures has greatly progressed, thus it becomes timely to review the ultrastructure of cilia and flagella. Briefly touching upon the typical features of a 9+2 axoneme, we dwell extensively on the transition zone, the singlet zone, the ciliary necklace, cap and crown. The relation of the singlet zone to sensory and/or motile function, the link of the ciliary cap to microtubule dynamics and to ciliary beat, the involvement of the ciliary crown in ovocyte and mucosal propulsion, and the role of the transition zone/the ciliary necklace in axonemal stabilization, autotomy and as a diffusion barrier will all be discussed.
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Affiliation(s)
- Cathy Fisch
- ATIGE Centriole et Pathologies Associées, INSERM/UEVE U829, 91000 Évry, France.
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19
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Winey M, Stemm-Wolf AJ, Giddings TH, Pearson CG. Cytological analysis of Tetrahymena thermophila. Methods Cell Biol 2012; 109:357-78. [PMID: 22444152 DOI: 10.1016/b978-0-12-385967-9.00013-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Since their first detection in pond water, large ciliates such as Tetrahymena thermophila, have captivated school children and scientists alike with the elegance of their swimming and the beauty of their cortical organization. Indeed, cytology - simply looking at cells - is an important component of most areas of study in cell biology and is particularly intriguing in the large, complex Tetrahymena cell. Cytological analysis of Tetrahymena is critical for the study of the microtubule cytoskeleton, membrane trafficking, complex nuclear movements and interactions, and the cellular remodeling during conjugation, to name a few topics. We briefly review previously reported cytological techniques for both light and electron microscopy, and point the reader to resources to learn about those protocols. We go on to present new and emerging technologies for the study of these marvelous cells. These include the use of fluorescent-protein tagging to localize cellular components in live cells, as well as for tracking the dynamic behavior of proteins using pulse labeling and fluorescence recovery after photobleaching. For electron microscopy, cellular and antigenic preservation has been improved with the use of cryofixation and freeze-substitution. The technologies described here advance Tetrahymena cell biology to the cutting-edge of cytological analysis.
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Affiliation(s)
- Mark Winey
- MCD Biology, University of Colorado at Boulder, 347 UCB, Boulder, Colorado 80309-0347, USA
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20
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Wloga D, Frankel J. From Molecules to Morphology: Cellular Organization of Tetrahymena thermophila. Methods Cell Biol 2012; 109:83-140. [DOI: 10.1016/b978-0-12-385967-9.00005-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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21
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Abstract
Eukaryotic cilia and flagella perform motility and sensory functions which are essential for cell survival in protozoans, and to organism development and homoeostasis in metazoans. Their ultrastructure has been studied from the early beginnings of electron microscopy, and these studies continue to contribute to much of our understanding about ciliary biology. In the light of the progress made in the visualization of cellular structures over the last decade, we revisit the ultrastructure of cilia and flagella. We briefly describe the typical features of a 9+2 axoneme before focusing extensively on the transition zone, the ciliary necklace, the singlet zone, the ciliary cap and the ciliary crown. We discuss how the singlet zone is linked to sensory and/or motile function, the contribution of the ciliary crown to ovocyte and mucosal propulsion, and the relationship between the ciliary cap and microtubule growth and shortening, and its relation to ciliary beat. We further examine the involvement of the transition zone/the ciliary necklace in axonemal stabilization, autotomy and as a diffusion barrier.
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22
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Vonderfecht T, Stemm-Wolf AJ, Hendershott M, Giddings TH, Meehl JB, Winey M. The two domains of centrin have distinct basal body functions in Tetrahymena. Mol Biol Cell 2011; 22:2221-34. [PMID: 21562224 PMCID: PMC3128525 DOI: 10.1091/mbc.e11-02-0151] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/15/2011] [Accepted: 04/29/2011] [Indexed: 11/11/2022] Open
Abstract
The basal body is a microtubule-organizing center responsible for organizing the cilium, a structure important for cell locomotion and sensing of the surrounding environment. A widely conserved basal body component is the Ca(2+)-binding protein centrin. Analyses of centrin function suggest a role in basal body assembly and stability; however, its molecular mechanisms remain unclear. Here we describe a mutagenic strategy to study the function and essential nature of the various structural features of Cen1 in the ciliate Tetrahymena. We find that the two domains of Cen1 are both essential, and examination of strains containing mutant CEN1 alleles indicates that there are two predominant basal body phenotypes: misorientation of newly assembled basal bodies and stability defects. The results also show that the two domains of Cen1 are able to bind Ca(2+) and that perturbation of Ca(2+) binding affects Cen1 function. In all, the data suggest that the two domains of Cen1 have distinct functions.
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Affiliation(s)
- Tyson Vonderfecht
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado–Boulder, Boulder, CO 80309
| | - Alexander J. Stemm-Wolf
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado–Boulder, Boulder, CO 80309
| | | | - Thomas H. Giddings
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado–Boulder, Boulder, CO 80309
| | - Janet B. Meehl
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado–Boulder, Boulder, CO 80309
| | - Mark Winey
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado–Boulder, Boulder, CO 80309
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23
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Giddings TH, Meehl JB, Pearson CG, Winey M. Electron Tomography and Immuno-labeling of Tetrahymena thermophila Basal Bodies. Methods Cell Biol 2010; 96:117-41. [DOI: 10.1016/s0091-679x(10)96006-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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