1
|
Lee C, Maier W, Jiang YY, Nakano K, Lechtreck KF, Gaertig J. Global and local functions of the Fused kinase ortholog CdaH in intracellular patterning in Tetrahymena. J Cell Sci 2024; 137:jcs261256. [PMID: 37667859 PMCID: PMC10565251 DOI: 10.1242/jcs.261256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/29/2023] [Indexed: 09/06/2023] Open
Abstract
Ciliates assemble numerous microtubular structures into complex cortical patterns. During ciliate division, the pattern is duplicated by intracellular segmentation that produces a tandem of daughter cells. In Tetrahymena thermophila, the induction and positioning of the division boundary involves two mutually antagonistic factors: posterior CdaA (cyclin E) and anterior CdaI (Hippo kinase). Here, we characterized the related cdaH-1 allele, which confers a pleiotropic patterning phenotype including an absence of the division boundary and an anterior-posterior mispositioning of the new oral apparatus. CdaH is a Fused or Stk36 kinase ortholog that localizes to multiple sites that correlate with the effects of its loss, including the division boundary and the new oral apparatus. CdaH acts downstream of CdaA to induce the division boundary and drives asymmetric cytokinesis at the tip of the posterior daughter. CdaH both maintains the anterior-posterior position of the new oral apparatus and interacts with CdaI to pattern ciliary rows within the oral apparatus. Thus, CdaH acts at multiple scales, from induction and positioning of structures on the cell-wide polarity axis to local organelle-level patterning.
Collapse
Affiliation(s)
- Chinkyu Lee
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Wolfgang Maier
- Bioinformatics, University of Freiburg, 79110 Freiburg, Germany
| | - Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Kentaro Nakano
- Degree Programs in Biology, Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
2
|
Larson BT. Perspectives on Principles of Cellular Behavior from the Biophysics of Protists. Integr Comp Biol 2023; 63:1405-1421. [PMID: 37496203 PMCID: PMC10755178 DOI: 10.1093/icb/icad106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023] Open
Abstract
Cells are the fundamental unit of biological organization. Although it may be easy to think of them as little more than the simple building blocks of complex organisms such as animals, single cells are capable of behaviors of remarkable apparent sophistication. This is abundantly clear when considering the diversity of form and function among the microbial eukaryotes, the protists. How might we navigate this diversity in the search for general principles of cellular behavior? Here, we review cases in which the intensive study of protists from the perspective of cellular biophysics has driven insight into broad biological questions of morphogenesis, navigation and motility, and decision making. We argue that applying such approaches to questions of evolutionary cell biology presents rich, emerging opportunities. Integrating and expanding biophysical studies across protist diversity, exploiting the unique characteristics of each organism, will enrich our understanding of general underlying principles.
Collapse
Affiliation(s)
- Ben T Larson
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
| |
Collapse
|
3
|
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.
Collapse
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 ()
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Soh AWJ, Pearson CG. Ciliate cortical organization and dynamics for cell motility: Comparing ciliates and vertebrates. J Eukaryot Microbiol 2022; 69:e12880. [PMID: 34897878 PMCID: PMC9188629 DOI: 10.1111/jeu.12880] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The generation of efficient fluid flow is crucial for organismal development and homeostasis, sexual reproduction, and motility. Multi-ciliated cells possess fields of motile cilia that beat in synchrony to propel fluid. Ciliary arrays are remarkably conserved in their organization and function. Ciliates have polarized multi-ciliary arrays (MCAs) to promote fluid flow for cell motility. The ciliate cortex is decorated with hundreds of basal bodies (BB) forming linear rows along the cell's anterior-posterior axis. BBs scaffold and position cilia to form the organized ciliary array. Nascent BBs assemble at the base of BBs. As nascent BBs mature, they integrate into the cortical BB and cytoskeletal network and nucleate their own cilium. The organization of MCAs is balanced between cortical stability and cortical dynamism. The cortical cytoskeletal network both establishes and maintains a stable organization of the MCA in the face of mechanical forces exerted by ciliary beating. At the same time, MCA organization is plastic, such that it remodels for optimal ciliary mobility during development and in response to environmental conditions. Such plasticity promotes effective feeding and ecological behavior required for these organisms. Together, these properties allow an organism to effectively sense, adapt to, and move through its environment.
Collapse
Affiliation(s)
- Adam W. J. Soh
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
| | - Chad G. Pearson
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
| |
Collapse
|
6
|
Abstract
Several tissues contain cells with multiple motile cilia that generate a fluid or particle flow to support development and organ functions; defective motility causes human disease. Developmental cues orient motile cilia, but how cilia are locked into their final position to maintain a directional flow is not understood. Here we find that the actin cytoskeleton is highly dynamic during early development of multiciliated cells (MCCs). While apical actin bundles become increasingly more static, subapical actin filaments are nucleated from the distal tip of ciliary rootlets. Anchorage of these subapical actin filaments requires the presence of microridge-like structures formed during MCC development, and the activity of Nonmuscle Myosin II. Optogenetic manipulation of Ezrin, a core component of the microridge actin-anchoring complex, or inhibition of Myosin Light Chain Kinase interfere with rootlet anchorage and orientation. These observations identify microridge-like structures as an essential component of basal body rootlet anchoring in MCCs. Motile cilia beat in a defined direction to orchestrate developmental programs, but also to execute janitorial tasks such as clearing airways. Here they show that motile cilia of the Xenopus epidermis are anchored to microridge-like membrane protrusions to maintain their directionality.
Collapse
|
7
|
Bouhouche K, Valentine MS, Le Borgne P, Lemullois M, Yano J, Lodh S, Nabi A, Tassin AM, Van Houten JL. Paramecium, a Model to Study Ciliary Beating and Ciliogenesis: Insights From Cutting-Edge Approaches. Front Cell Dev Biol 2022; 10:847908. [PMID: 35359441 PMCID: PMC8964087 DOI: 10.3389/fcell.2022.847908] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/14/2022] [Indexed: 12/30/2022] Open
Abstract
Cilia are ubiquitous and highly conserved extensions that endow the cell with motility and sensory functions. They were present in the first eukaryotes and conserved throughout evolution (Carvalho-Santos et al., 2011). Paramecium has around 4,000 motile cilia on its surface arranged in longitudinal rows, beating in waves to ensure movement and feeding. As with cilia in other model organisms, direction and speed of Paramecium ciliary beating is under bioelectric control of ciliary ion channels. In multiciliated cells of metazoans as well as paramecia, the cilia become physically entrained to beat in metachronal waves. This ciliated organism, Paramecium, is an attractive model for multidisciplinary approaches to dissect the location, structure and function of ciliary ion channels and other proteins involved in ciliary beating. Swimming behavior also can be a read-out of the role of cilia in sensory signal transduction. A cilium emanates from a BB, structurally equivalent to the centriole anchored at the cell surface, and elongates an axoneme composed of microtubule doublets enclosed in a ciliary membrane contiguous with the plasma membrane. The connection between the BB and the axoneme constitutes the transition zone, which serves as a diffusion barrier between the intracellular space and the cilium, defining the ciliary compartment. Human pathologies affecting cilia structure or function, are called ciliopathies, which are caused by gene mutations. For that reason, the molecular mechanisms and structural aspects of cilia assembly and function are actively studied using a variety of model systems, ranging from unicellular organisms to metazoa. In this review, we will highlight the use of Paramecium as a model to decipher ciliary beating mechanisms as well as high resolution insights into BB structure and anchoring. We will show that study of cilia in Paramecium promotes our understanding of cilia formation and function. In addition, we demonstrate that Paramecium could be a useful tool to validate candidate genes for ciliopathies.
Collapse
Affiliation(s)
- K. Bouhouche
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | | | - P. Le Borgne
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - M. Lemullois
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - J. Yano
- Department of Biology, University of Vermont, Burlington, VT, United States
| | - S. Lodh
- Biological Sciences, Marquette University, Milwaukee, WI, United States
| | - A. Nabi
- Luminex, Austin, TX, United States
| | - A. M. Tassin
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - J. L. Van Houten
- Department of Biology, University of Vermont, Burlington, VT, United States
| |
Collapse
|
8
|
Cole E, Gaertig J. Anterior-posterior pattern formation in ciliates. J Eukaryot Microbiol 2022; 69:e12890. [PMID: 35075744 PMCID: PMC9309198 DOI: 10.1111/jeu.12890] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/06/2022] [Accepted: 01/17/2022] [Indexed: 11/29/2022]
Abstract
As single cells, ciliates build, duplicate, and even regenerate complex cortical patterns by largely unknown mechanisms that precisely position organelles along two cell‐wide axes: anterior–posterior and circumferential (left–right). We review our current understanding of intracellular patterning along the anterior–posterior axis in ciliates, with emphasis on how the new pattern emerges during cell division. We focus on the recent progress at the molecular level that has been driven by the discovery of genes whose mutations cause organelle positioning defects in the model ciliate Tetrahymena thermophila. These investigations have revealed a network of highly conserved kinases that are confined to either anterior or posterior domains in the cell cortex. These pattern‐regulating kinases create zones of cortical inhibition that by exclusion determine the precise placement of organelles. We discuss observations and models derived from classical microsurgical experiments in large ciliates (including Stentor) and interpret them in light of recent molecular findings in Tetrahymena. In particular, we address the involvement of intracellular gradients as vehicles for positioning organelles along the anterior‐posterior axis.
Collapse
Affiliation(s)
- Eric Cole
- Biology Department, St. Olaf College, Northfield, MN, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| |
Collapse
|
9
|
Plastic cell morphology changes during dispersal. iScience 2021; 24:102915. [PMID: 34430806 PMCID: PMC8367785 DOI: 10.1016/j.isci.2021.102915] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/11/2021] [Accepted: 07/23/2021] [Indexed: 11/22/2022] Open
Abstract
Dispersal is the movement of organisms from one habitat to another that potentially results in gene flow. It is often plastic, allowing organisms to adjust dispersal movements depending on environmental conditions. A fundamental aim in ecology is to understand the determinants underlying dispersal and its plasticity. We utilized 22 strains of the ciliate Tetrahymena thermophila to determine if different phenotypic dispersal strategies co-exist within a species and which mechanisms underlie this variability. We quantified the cell morphologies impacting cell motility and dispersal. Distinct differences in innate cellular morphology and dispersal rates were detected, but no universally utilized combinations of morphological parameters correlate with dispersal. Rather, multiple distinct and plastic morphological changes impact cilia-dependent motility during dispersal, especially in proficient dispersing strains facing challenging environmental conditions. Combining ecology and cell biology experiments, we show that dispersal can be promoted through plastic motility-associated changes to cell morphology and motile cilia.
Collapse
|
10
|
Abstract
To gain a holistic understanding of cellular function, we must understand not just the role of individual organelles, but also how multiple macromolecular assemblies function collectively. Centrioles produce fundamental cellular processes through their ability to organise cytoskeletal fibres. In addition to nucleating microtubules, centrioles form lesser-known polymers, termed rootlets. Rootlets were identified over a 100 years ago and have been documented morphologically since by electron microscopy in different eukaryotic organisms. Rootlet-knockout animals have been created in various systems, providing insight into their physiological functions. However, the precise structure and function of rootlets is still enigmatic. Here, I consider common themes of rootlet function and assembly across diverse cellular systems. I suggest that the capability of rootlets to form physical links from centrioles to other cellular structures is a general principle unifying their functions in diverse cells and serves as an example of how cellular function arises from collective organellar activity.
Collapse
Affiliation(s)
- Robert Mahen
- The Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| |
Collapse
|
11
|
Ruehle MD, Stemm-Wolf AJ, Pearson CG. Sas4 links basal bodies to cell division via Hippo signaling. J Cell Biol 2021; 219:151794. [PMID: 32435796 PMCID: PMC7401811 DOI: 10.1083/jcb.201906183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 03/10/2020] [Accepted: 05/01/2020] [Indexed: 01/07/2023] Open
Abstract
Basal bodies (BBs) are macromolecular complexes required for the formation and cortical positioning of cilia. Both BB assembly and DNA replication are tightly coordinated with the cell cycle to ensure their accurate segregation and propagation to daughter cells, but the mechanisms ensuring coordination are unclear. The Tetrahymena Sas4/CPAP protein is enriched at assembling BBs, localizing to the core BB structure and to the base of BB-appendage microtubules and striated fiber. Sas4 is necessary for BB assembly and cortical microtubule organization, and Sas4 loss disrupts cell division furrow positioning and DNA segregation. The Hippo signaling pathway is known to regulate cell division furrow position, and Hippo molecules localize to BBs and BB-appendages. We find that Sas4 loss disrupts localization of the Hippo activator, Mob1, suggesting that Sas4 mediates Hippo activity by promoting scaffolds for Mob1 localization to the cell cortex. Thus, Sas4 links BBs with an ancient signaling pathway known to promote the accurate and symmetric segregation of the genome.
Collapse
Affiliation(s)
- Marisa D Ruehle
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Alexander J Stemm-Wolf
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Bayless BA, Navarro FM, Winey M. Motile Cilia: Innovation and Insight From Ciliate Model Organisms. Front Cell Dev Biol 2019; 7:265. [PMID: 31737631 PMCID: PMC6838636 DOI: 10.3389/fcell.2019.00265] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/18/2019] [Indexed: 12/15/2022] Open
Abstract
Ciliates are a powerful model organism for the study of basal bodies and motile cilia. These single-celled protists contain hundreds of cilia organized in an array making them an ideal system for both light and electron microscopy studies. Isolation and subsequent proteomic analysis of both cilia and basal bodies have been carried out to great success in ciliates. These studies reveal that ciliates share remarkable protein conservation with metazoans and have identified a number of essential basal body/ciliary proteins. Ciliates also boast a genetic and molecular toolbox that allows for facile manipulation of ciliary genes. Reverse genetics studies in ciliates have expanded our understanding of how cilia are positioned within an array, assembled, stabilized, and function at a molecular level. The advantages of cilia number coupled with a robust genetic and molecular toolbox have established ciliates as an ideal system for motile cilia and basal body research and prove a promising system for future research.
Collapse
Affiliation(s)
- Brian A Bayless
- Department of Biology, Santa Clara University, Santa Clara, CA, United States
| | - Francesca M Navarro
- Department of Biology, Santa Clara University, Santa Clara, CA, United States
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| |
Collapse
|
14
|
Nabi A, Yano J, Valentine MS, Picariello T, Van Houten JL. SF-Assemblin genes in Paramecium: phylogeny and phenotypes of RNAi silencing on the ciliary-striated rootlets and surface organization. Cilia 2019; 8:2. [PMID: 31673332 PMCID: PMC6819543 DOI: 10.1186/s13630-019-0062-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 10/10/2019] [Indexed: 11/17/2022] Open
Abstract
Background Cilia emanate from basal bodies just underneath the cell membrane. Basal bodies must withstand torque from the ciliary beat and be appropriately spaced for cilia to beat in metachronal waves. Basal body rootlets provide stability for motile cilia. Paramecium has three. Our focus is on the largest one, the striated rootlet (SR). Paramecium basal bodies align in straight rows. Previously we found a potential role for the SR in this alignment. Here we present a phylogeny of the Paramecium homologs of the SF-Assemblin gene of the SR of Chlamydomonas, and the organization of these genes. We describe the phenotypes from RNA interference (RNAi) silencing of genes and gene groups. Methods Phenotypes of the RNAi depletions were characterized by immunofluorescence (IF), electron microscopy, and mass spectrometry. Results We found 30 genes for Paramecium SF-Assemblin homologs (SFA) organized into 13 Paralog Groups (further categorized in five Structural Groups). Representatives of Paralog Groups were found in the SRs. Silencing the transcripts of any of the Structural Groups correlates with misaligned rows of basal bodies, SRs, and cortical units. The silencing of Structural Groups was key and gave us the ability to systematically disrupt SR structures and cell surface organization. Conclusions Silencing of SFA genes and Paralog Groups shows no effects on the SR or the cell surface organization. Silencing of the larger Structural Groups has an enormous impact on rows of basal bodies, SRs and cortical units, and SR striations, and length. Misaligned basal bodies have cilia causing the cells to swim in abnormal paths.
Collapse
Affiliation(s)
- Ashikun Nabi
- 1University of Vermont, Burlington, VT 05405 USA.,4Present Address: Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511 USA
| | - Junji Yano
- 1University of Vermont, Burlington, VT 05405 USA
| | - Megan S Valentine
- 2State University of New York at Plattsburgh, Plattsburgh, NY 12901 USA
| | - Tyler Picariello
- 3University of Massachusetts Medical School, Worcester, MA 01655 USA
| | | |
Collapse
|
15
|
Soares H, Carmona B, Nolasco S, Viseu Melo L. Polarity in Ciliate Models: From Cilia to Cell Architecture. Front Cell Dev Biol 2019; 7:240. [PMID: 31681771 PMCID: PMC6813674 DOI: 10.3389/fcell.2019.00240] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/01/2019] [Indexed: 12/21/2022] Open
Abstract
Tetrahymena and Paramecium are highly differentiated unicellular organisms with elaborated cortical patterns showing a regular arrangement of hundreds to thousands of basal bodies in longitudinal rows that extend from the anterior to the posterior region of the cell. Thus both ciliates exhibit a permanent antero–posterior axis and left–right asymmetry. This cell polarity is reflected in the direction of the structures nucleated around each basal body such as the ciliary rootlets. Studies in these ciliates showed that basal bodies assemble two types of cilia, the cortical cilia and the cilia of the oral apparatus, a complex structure specialized in food capture. These two cilia types display structural differences at their tip domain. Basal bodies possessing distinct compositions creating specialized landmarks are also present. Cilia might be expected to express and transmit polarities throughout signaling pathways given their recognized role in signal transduction. This review will focus on how local polarities in basal bodies/cilia are regulated and transmitted through cell division in order to maintain the global polarity and shape of these cells and locally constrain the interpretation of signals by different cilia. We will also discuss ciliates as excellent biological models to study development and morphogenetic mechanisms and their relationship with cilia diversity and function in metazoans.
Collapse
Affiliation(s)
- Helena Soares
- Centro de Química e Bioquímica/Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.,Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Bruno Carmona
- Centro de Química e Bioquímica/Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.,Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Sofia Nolasco
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal.,CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal
| | - Luís Viseu Melo
- Physics Department and CEFEMA, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
16
|
Jokura K, Shibata D, Yamaguchi K, Shiba K, Makino Y, Shigenobu S, Inaba K. CTENO64 Is Required for Coordinated Paddling of Ciliary Comb Plate in Ctenophores. Curr Biol 2019; 29:3510-3516.e4. [DOI: 10.1016/j.cub.2019.08.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/10/2019] [Accepted: 08/21/2019] [Indexed: 12/12/2022]
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Wan KY. Coordination of eukaryotic cilia and flagella. Essays Biochem 2018; 62:829-838. [PMID: 30464007 PMCID: PMC6281475 DOI: 10.1042/ebc20180029] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 12/14/2022]
Abstract
Propulsion by slender cellular appendages called cilia and flagella is an ancient means of locomotion. Unicellular organisms evolved myriad strategies to propel themselves in fluid environments, often involving significant differences in flagella number, localisation and modes of actuation. Remarkably, these appendages are highly conserved, occurring in many complex organisms such as humans, where they may be found generating physiological flows when attached to surfaces (e.g. airway epithelial cilia), or else conferring motility to male gametes (e.g. undulations of sperm flagella). Where multiple cilia arise, their movements are often observed to be highly coordinated. Here I review the two main mechanisms for motile cilia coordination, namely, intracellular and hydrodynamic, and discuss their relative importance in different ciliary systems.
Collapse
Affiliation(s)
- Kirsty Y Wan
- Living Systems Institute, University of Exeter, Exeter, U.K.
- College of Engineering Mathematics and Physical Sciences, University of Exeter, Exeter, U.K
| |
Collapse
|
19
|
Chlamydomonas Basal Bodies as Flagella Organizing Centers. Cells 2018; 7:cells7070079. [PMID: 30018231 PMCID: PMC6070942 DOI: 10.3390/cells7070079] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 11/17/2022] Open
Abstract
During ciliogenesis, centrioles convert to membrane-docked basal bodies, which initiate the formation of cilia/flagella and template the nine doublet microtubules of the flagellar axoneme. The discovery that many human diseases and developmental disorders result from defects in flagella has fueled a strong interest in the analysis of flagellar assembly. Here, we will review the structure, function, and development of basal bodies in the unicellular green alga Chlamydomonas reinhardtii, a widely used model for the analysis of basal bodies and flagella. Intraflagellar transport (IFT), a flagella-specific protein shuttle critical for ciliogenesis, was first described in C. reinhardtii. A focus of this review will be on the role of the basal bodies in organizing the IFT machinery.
Collapse
|
20
|
Jiang YY, Maier W, Baumeister R, Minevich G, Joachimiak E, Ruan Z, Kannan N, Clarke D, Frankel J, Gaertig J. The Hippo Pathway Maintains the Equatorial Division Plane in the Ciliate Tetrahymena. Genetics 2017; 206:873-888. [PMID: 28413159 PMCID: PMC5499192 DOI: 10.1534/genetics.117.200766] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/29/2017] [Indexed: 12/30/2022] Open
Abstract
The mechanisms that govern pattern formation within the cell are poorly understood. Ciliates carry on their surface an elaborate pattern of cortical organelles that are arranged along the anteroposterior and circumferential axes by largely unknown mechanisms. Ciliates divide by tandem duplication: the cortex of the predivision cell is remodeled into two similarly sized and complete daughters. In the conditional cdaI-1 mutant of Tetrahymena thermophila, the division plane migrates from its initially correct equatorial position toward the cell's anterior, resulting in unequal cell division, and defects in nuclear divisions and cytokinesis. We used comparative whole genome sequencing to identify the cause of cdaI-1 as a mutation in a Hippo/Mst kinase. CdaI is a cortical protein with a cell cycle-dependent, highly polarized localization. Early in cell division, CdaI marks the anterior half of the cell, and later concentrates at the posterior end of the emerging anterior daughter. Despite the strong association of CdaI with the new posterior cell end, the cdaI-1 mutation does not affect the patterning of the new posterior cortical organelles. We conclude that, in Tetrahymena, the Hippo pathway maintains an equatorial position of the fission zone, and, by this activity, specifies the relative dimensions of the anterior and posterior daughter cell.
Collapse
Affiliation(s)
- Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Wolfgang Maier
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
| | - Ralf Baumeister
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, 79104 Germany
| | - Gregory Minevich
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Diamond Clarke
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Joseph Frankel
- Department of Biology, University of Iowa, Iowa City, Iowa 52242
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| |
Collapse
|
21
|
Tetrahymena as a Unicellular Model Eukaryote: Genetic and Genomic Tools. Genetics 2017; 203:649-65. [PMID: 27270699 DOI: 10.1534/genetics.114.169748] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/08/2016] [Indexed: 12/12/2022] Open
Abstract
Tetrahymena thermophila is a ciliate model organism whose study has led to important discoveries and insights into both conserved and divergent biological processes. In this review, we describe the tools for the use of Tetrahymena as a model eukaryote, including an overview of its life cycle, orientation to its evolutionary roots, and methodological approaches to forward and reverse genetics. Recent genomic tools have expanded Tetrahymena's utility as a genetic model system. With the unique advantages that Tetrahymena provide, we argue that it will continue to be a model organism of choice.
Collapse
|
22
|
Bengueddach H, Lemullois M, Aubusson-Fleury A, Koll F. Basal body positioning and anchoring in the multiciliated cell Paramecium tetraurelia: roles of OFD1 and VFL3. Cilia 2017; 6:6. [PMID: 28367320 PMCID: PMC5374602 DOI: 10.1186/s13630-017-0050-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/23/2017] [Indexed: 01/01/2023] Open
Abstract
Background The development of a ciliary axoneme requires the correct docking of the basal body at cytoplasmic vesicles or plasma membrane. In the multiciliated cell Paramecium, three conserved proteins, FOR20, Centrin 2, and Centrin 3 participate in this process, FOR20 and Centrin 2 being involved in the assembly of the transition zone. We investigated the function of two other evolutionary conserved proteins, OFD1 and VFL3, likely involved in this process. Results In Paramecium tetraurelia, a single gene encodes OFD1, while four genes encode four isoforms of VFL3, grouped into two families, VFL3-A and VFL3-B. Depletion of OFD1 and the sole VFL3-A family impairs basal body docking. Loss of OFD1 yields a defective assembly of the basal body distal part. Like FOR20, OFD1 is recruited early during basal body assembly and localizes at the transition zone between axoneme and membrane at the level of the microtubule doublets. While the recruitment of OFD1 and Centrin 2 proceed independently, the localizations of OFD1 and FOR20 at the basal body are interdependent. In contrast, in VFL3-A depleted cells, the unanchored basal bodies harbor a fully organized distal part but display an abnormal distribution of their associated rootlets which mark their rotational asymmetry. VFL3-A, which is required for the recruitment of Centrin 3, is transiently present near the basal bodies at an early step of their duplication. VFL3-A localizes at the junction between the striated rootlet and the basal body. Conclusion Our results demonstrate the conserved role of OFD1 in the anchoring mechanisms of motile cilia and establish its relations with FOR20 and Centrin 2. They support the hypothesis of its association with microtubule doublets. They suggest that the primary defect of VFL3 depletion is a loss of the rotational asymmetry of the basal body which specifies the sites of assembly of the appendages which guide the movement of basal bodies toward the cell surface. The localization of VFL3 outside of the basal body suggests that extrinsic factors could control this asymmetry. Electronic supplementary material The online version of this article (doi:10.1186/s13630-017-0050-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Hakim Bengueddach
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Michel Lemullois
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Anne Aubusson-Fleury
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - France Koll
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| |
Collapse
|
23
|
SHG-specificity of cellular Rootletin filaments enables naïve imaging with universal conservation. Sci Rep 2017; 7:39967. [PMID: 28059168 PMCID: PMC5216331 DOI: 10.1038/srep39967] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/30/2016] [Indexed: 02/01/2023] Open
Abstract
Despite growing demand for truly naïve imaging, label-free observation of cilium-related structure remains challenging, and validation of the pertinent molecules is correspondingly difficult. In this study, in retinas and cultured cells, we distinctively visualized Rootletin filaments in rootlets in the second harmonic generation (SHG) channel, integrated in custom coherent nonlinear optical microscopy (CNOM) with a simple, compact, and ultra-broadband supercontinuum light source. This SHG signal was primarily detected on rootlets of connecting cilia in the retinal photoreceptor and was validated by colocalization with anti-Rootletin staining. Transfection of cells with Rootletin fragments revealed that the SHG signal can be ascribed to filaments assembled from the R234 domain, but not to cross-striations assembled from the R123 domain. Consistent with this, Rootletin-depleted cells lacked SHG signal expected as centrosome linker. As a proof of concept, we confirmed that similar fibrous SHG was observed even in unicellular ciliates. These findings have potential for broad applications in clinical diagnosis and biophysical experiments with various organisms.
Collapse
|
24
|
Affiliation(s)
- F. Paul Doerder
- Department of Biological, Geological and Environmental Sciences; Cleveland State University; Cleveland Ohio 44115 USA
| | - Joseph Frankel
- Department of Biology; University of Iowa; Iowa City Iowa 52242 USA
| |
Collapse
|
25
|
Guerrier S, Plattner H, Richardson E, Dacks JB, Turkewitz AP. An evolutionary balance: conservation vs innovation in ciliate membrane trafficking. Traffic 2016; 18:18-28. [PMID: 27696651 DOI: 10.1111/tra.12450] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/20/2016] [Accepted: 09/20/2016] [Indexed: 12/15/2022]
Abstract
As most of eukaryotic diversity lies in single-celled protists, they represent unique opportunities to ask questions about the balance of conservation and innovation in cell biological features. Among free-living protists the ciliates offer ease of culturing, a rich array of experimental approaches, and versatile molecular tools, particularly in Tetrahymena thermophila and Paramecium tetraurelia. These attributes have been exploited by researchers to analyze a wealth of cellular structures in these large and complex cells. This mini-review focuses on 3 aspects of ciliate membrane dynamics, all linked with endolysosomal trafficking. First is nutrition based on phagocytosis and maturation of food vacuoles. Secondly, we discuss regulated exocytosis from vesicles that have features of both dense core secretory granules but also lysosome-related organelles. The third topic is the targeting, breakdown and resorption of parental nuclei in mating partners. For all 3 phenomena, it is clear that elements of the canonical membrane-trafficking system have been retained and in some cases repurposed. In addition, there is evidence that recently evolved, lineage-specific proteins provide determinants in these pathways.
Collapse
Affiliation(s)
| | - Helmut Plattner
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Joel B Dacks
- Department of Cell Biology, University of Alberta, Canada
| | - Aaron P Turkewitz
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois
| |
Collapse
|
26
|
Whole Genome Sequencing Identifies a Novel Factor Required for Secretory Granule Maturation in Tetrahymena thermophila. G3-GENES GENOMES GENETICS 2016; 6:2505-16. [PMID: 27317773 PMCID: PMC4978903 DOI: 10.1534/g3.116.028878] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Unbiased genetic approaches have a unique ability to identify novel genes associated with specific biological pathways. Thanks to next generation sequencing, forward genetic strategies can be expanded to a wider range of model organisms. The formation of secretory granules, called mucocysts, in the ciliate Tetrahymena thermophila relies, in part, on ancestral lysosomal sorting machinery, but is also likely to involve novel factors. In prior work, multiple strains with defects in mucocyst biogenesis were generated by nitrosoguanidine mutagenesis, and characterized using genetic and cell biological approaches, but the genetic lesions themselves were unknown. Here, we show that analyzing one such mutant by whole genome sequencing reveals a novel factor in mucocyst formation. Strain UC620 has both morphological and biochemical defects in mucocyst maturation-a process analogous to dense core granule maturation in animals. Illumina sequencing of a pool of UC620 F2 clones identified a missense mutation in a novel gene called MMA1 (Mucocyst maturation). The defects in UC620 were rescued by expression of a wild-type copy of MMA1, and disrupting MMA1 in an otherwise wild-type strain phenocopies UC620. The product of MMA1, characterized as a CFP-tagged copy, encodes a large soluble cytosolic protein. A small fraction of Mma1p-CFP is pelletable, which may reflect association with endosomes. The gene has no identifiable homologs except in other Tetrahymena species, and therefore represents an evolutionarily recent innovation that is required for granule maturation.
Collapse
|
27
|
Meehl JB, Bayless BA, Giddings TH, Pearson CG, Winey M. Tetrahymena Poc1 ensures proper intertriplet microtubule linkages to maintain basal body integrity. Mol Biol Cell 2016; 27:2394-403. [PMID: 27251062 PMCID: PMC4966981 DOI: 10.1091/mbc.e16-03-0165] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/27/2016] [Indexed: 12/31/2022] Open
Abstract
Basal bodies comprise nine symmetric triplet microtubules that anchor forces produced by the asymmetric beat pattern of motile cilia. The ciliopathy protein Poc1 stabilizes basal bodies through an unknown mechanism. In poc1∆ cells, electron tomography reveals subtle defects in the organization of intertriplet linkers (A-C linkers) that connect adjacent triplet microtubules. Complete triplet microtubules are lost preferentially near the posterior face of the basal body. Basal bodies that are missing triplets likely remain competent to assemble new basal bodies with nine triplet microtubules, suggesting that the mother basal body microtubule structure does not template the daughter. Our data indicate that Poc1 stabilizes basal body triplet microtubules through linkers between neighboring triplets. Without this stabilization, specific triplet microtubules within the basal body are more susceptible to loss, probably due to force distribution within the basal body during ciliary beating. This work provides insights into how the ciliopathy protein Poc1 maintains basal body integrity.
Collapse
Affiliation(s)
- Janet B Meehl
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309
| | - Brian A Bayless
- Department of Cell and Developmental Biology, University of Colorado-Anschutz Medical Campus, Aurora, CO 80045
| | - Thomas H Giddings
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado-Anschutz Medical Campus, Aurora, CO 80045
| | - Mark Winey
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309
| |
Collapse
|
28
|
Wan KY, Goldstein RE. Coordinated beating of algal flagella is mediated by basal coupling. Proc Natl Acad Sci U S A 2016; 113:E2784-93. [PMID: 27140605 PMCID: PMC4878519 DOI: 10.1073/pnas.1518527113] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cilia and flagella often exhibit synchronized behavior; this includes phase locking, as seen in Chlamydomonas, and metachronal wave formation in the respiratory cilia of higher organisms. Since the observations by Gray and Rothschild of phase synchrony of nearby swimming spermatozoa, it has been a working hypothesis that synchrony arises from hydrodynamic interactions between beating filaments. Recent work on the dynamics of physically separated pairs of flagella isolated from the multicellular alga Volvox has shown that hydrodynamic coupling alone is sufficient to produce synchrony. However, the situation is more complex in unicellular organisms bearing few flagella. We show that flagella of Chlamydomonas mutants deficient in filamentary connections between basal bodies display markedly different synchronization from the wild type. We perform micromanipulation on configurations of flagella and conclude that a mechanism, internal to the cell, must provide an additional flagellar coupling. In naturally occurring species with 4, 8, or even 16 flagella, we find diverse symmetries of basal body positioning and of the flagellar apparatus that are coincident with specific gaits of flagellar actuation, suggesting that it is a competition between intracellular coupling and hydrodynamic interactions that ultimately determines the precise form of flagellar coordination in unicellular algae.
Collapse
Affiliation(s)
- Kirsty Y Wan
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Raymond E Goldstein
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| |
Collapse
|
29
|
Abstract
Tetrahymena thermophila is a ciliate with hundreds of cilia primarily used for cellular motility. These cells propel themselves by generating hydrodynamic forces through coordinated ciliary beating. The coordination of cilia is ensured by the polarized organization of basal bodies (BBs), which exhibit remarkable structural and molecular conservation with BBs in other eukaryotes. During each cell cycle, massive BB assembly occurs and guarantees that future Tetrahymena cells gain a full complement of BBs and their associated cilia. BB duplication occurs next to existing BBs, and the predictable patterning of new BBs is facilitated by asymmetric BB accessory structures that are integrated with a membrane-associated cytoskeletal network. The large number of BBs combined with robust molecular genetics merits Tetrahymena as a unique model system to elucidate the fundamental events of BB assembly and organization.
Collapse
Affiliation(s)
- Brian A Bayless
- Department of Cell and Developmental Biology, University of Colorado-Anschutz Medical Campus, 2801 E. 17th Ave, Aurora, CO 80045-2537 USA
| | - Domenico F Galati
- Department of Cell and Developmental Biology, University of Colorado-Anschutz Medical Campus, 2801 E. 17th Ave, Aurora, CO 80045-2537 USA
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado-Anschutz Medical Campus, 2801 E. 17th Ave, Aurora, CO 80045-2537 USA
| |
Collapse
|
30
|
Galati DF, Abuin DS, Tauber GA, Pham AT, Pearson CG. Automated image analysis reveals the dynamic 3-dimensional organization of multi-ciliary arrays. Biol Open 2015; 5:20-31. [PMID: 26700722 PMCID: PMC4728305 DOI: 10.1242/bio.014951] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Multi-ciliated cells (MCCs) use polarized fields of undulating cilia (ciliary array) to produce fluid flow that is essential for many biological processes. Cilia are positioned by microtubule scaffolds called basal bodies (BBs) that are arranged within a spatially complex 3-dimensional geometry (3D). Here, we develop a robust and automated computational image analysis routine to quantify 3D BB organization in the ciliate, Tetrahymena thermophila. Using this routine, we generate the first morphologically constrained 3D reconstructions of Tetrahymena cells and elucidate rules that govern the kinetics of MCC organization. We demonstrate the interplay between BB duplication and cell size expansion through the cell cycle. In mutant cells, we identify a potential BB surveillance mechanism that balances large gaps in BB spacing by increasing the frequency of closely spaced BBs in other regions of the cell. Finally, by taking advantage of a mutant predisposed to BB disorganization, we locate the spatial domains that are most prone to disorganization by environmental stimuli. Collectively, our analyses reveal the importance of quantitative image analysis to understand the principles that guide the 3D organization of MCCs. Summary: We develop an automated computational image analysis routine to quantify basal body organization, which detects subtle spatial phenotypes resulting from environmental and genetic perturbations.
Collapse
Affiliation(s)
- Domenico F Galati
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, 2801 East 17th Ave, Aurora, CO 80045-2537, USA
| | - David S Abuin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, 2801 East 17th Ave, Aurora, CO 80045-2537, USA
| | - Gabriel A Tauber
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, 2801 East 17th Ave, Aurora, CO 80045-2537, USA
| | - Andrew T Pham
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, 2801 East 17th Ave, Aurora, CO 80045-2537, USA
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, 2801 East 17th Ave, Aurora, CO 80045-2537, USA
| |
Collapse
|
31
|
Plattner H. Signalling in ciliates: long- and short-range signals and molecular determinants for cellular dynamics. Biol Rev Camb Philos Soc 2015; 92:60-107. [PMID: 26487631 DOI: 10.1111/brv.12218] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 07/28/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022]
Abstract
In ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in Paramecium tetraurelia, Paramecium multimicronucleatum and Tetrahymena thermophila and in part also in Euplotes raikovi. Electrophysiology of ciliary activity in Paramecium spp. is a most successful example. Established signalling mechanisms include plasmalemmal ion channels, recently established intracellular Ca2+ -release channels, as well as signalling by cyclic nucleotides and Ca2+ . Ca2+ -binding proteins (calmodulin, centrin) and Ca2+ -activated enzymes (kinases, phosphatases) are involved. Many organelles are endowed with specific molecules cooperating in signalling for intracellular transport and targeted delivery. Among them are recently specified soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), monomeric GTPases, H+ -ATPase/pump, actin, etc. Little specification is available for some key signal transducers including mechanosensitive Ca2+ -channels, exocyst complexes and Ca2+ -sensor proteins for vesicle-vesicle/membrane interactions. The existence of heterotrimeric G-proteins and of G-protein-coupled receptors is still under considerable debate. Serine/threonine kinases dominate by far over tyrosine kinases (some predicted by phosphoproteomic analyses). Besides short-range signalling, long-range signalling also exists, e.g. as firmly installed microtubular transport rails within epigenetically determined patterns, thus facilitating targeted vesicle delivery. By envisaging widely different phenomena of signalling and subcellular dynamics, it will be shown (i) that important pathways of signalling and cellular dynamics are established already in ciliates, (ii) that some mechanisms diverge from higher eukaryotes and (iii) that considerable uncertainties still exist about some essential aspects of signalling.
Collapse
Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, PO Box M625, 78457, Konstanz, Germany
| |
Collapse
|
32
|
Turk E, Wills AA, Kwon T, Sedzinski J, Wallingford JB, Stearns T. Zeta-Tubulin Is a Member of a Conserved Tubulin Module and Is a Component of the Centriolar Basal Foot in Multiciliated Cells. Curr Biol 2015; 25:2177-83. [PMID: 26234217 DOI: 10.1016/j.cub.2015.06.063] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/12/2015] [Accepted: 06/24/2015] [Indexed: 10/23/2022]
Abstract
There are six members of the tubulin superfamily in eukaryotes. Alpha- and beta-tubulin form a heterodimer that polymerizes to form microtubules, and gamma-tubulin nucleates microtubules as a component of the gamma-tubulin ring complex. Alpha-, beta-, and gamma-tubulin are conserved in all eukaryotes. In contrast, delta- and epsilon-tubulin are conserved in many, but not all, eukaryotes and are associated with centrioles, although their molecular function is unclear. Zeta-tubulin is the sixth and final member of the tubulin superfamily and is largely uncharacterized. We find that zeta-, epsilon-, and delta-tubulin form an evolutionarily co-conserved module, the ZED module, that has been lost at several junctions in eukaryotic evolution and that zeta- and delta-tubulin are evolutionarily interchangeable. Humans lack zeta-tubulin but have delta-tubulin. In Xenopus multiciliated cells, zeta-tubulin is a component of the basal foot, a centriolar appendage that connects centrioles to the apical cytoskeleton, and co-localizes there with epsilon-tubulin. Depletion of zeta-tubulin results in disorganization of centriole distribution and polarity in multiciliated cells. In contrast with multiciliated cells, zeta-tubulin in cycling cells does not localize to centrioles and is associated with the TRiC/CCT cytoplasmic chaperone complex. We conclude that zeta-tubulin facilitates interactions between the centrioles and the apical cytoskeleton as a component of the basal foot in differentiated cells and propose that the ZED tubulins are important for centriole functionalization and orientation of centrioles with respect to cellular polarity axes.
Collapse
Affiliation(s)
- Erin Turk
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Airon A Wills
- Department of Molecular Biosciences and Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Taejoon Kwon
- Department of Molecular Biosciences and Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jakub Sedzinski
- Department of Molecular Biosciences and Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - John B Wallingford
- Department of Molecular Biosciences and Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute
| | - Tim Stearns
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
| |
Collapse
|
33
|
Short B. Understanding the DisAp-pearance of cilia orientation. J Biophys Biochem Cytol 2014. [PMCID: PMC4274263 DOI: 10.1083/jcb.2076iti2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|