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Tani Y, Yanagisawa H, Yagi T, Kikkawa M. Structure and function of FAP47 in the central pair apparatus of Chlamydomonas flagella. Cytoskeleton (Hoboken) 2024. [PMID: 38899546 DOI: 10.1002/cm.21882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 05/18/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024]
Abstract
Motile cilia have a so-called "9 + 2" structure, which consists of nine doublet microtubules and a central pair apparatus. The central pair apparatus (CA) is thought to interact mechanically with radial spokes and to control the flagellar beating. Recently, the components of the CA have been identified by proteomic and genomic analyses. Still, the mechanism of how the CA contributes to ciliary motility has much to be revealed. Here, we focused on one CA component with a large molecular weight: FAP47, and its relationship with two other CA components with large molecular weight: HYDIN, and CPC1. The analyses of motility of the Chlamydomonas mutants revealed that in contrast to cpc1 or hydin, which swam more slowly than the wild type, fap47 cells displayed wild-type swimming velocity and flagellar beat frequency, yet interestingly, fap47 cells have phototaxis defects and swim straighter than the wild-type cells. Furthermore, the double mutant fap47cpc1 and fap47hydin showed significantly slower swimming than cpc1 and hydin cells, and the motility defect of fap47cpc1 was rescued to the cpc1 level with GFP-tagged FAP47, indicating that the lack of FAP47 makes the motility defect of cpc1 worse. Cryo-electron tomography demonstrated that the fap47 lacks a part of the C1-C2 bridge of CA. Taken together, these observations indicate that FAP47 maintains the structural stiffness of the CA, which is important for flagellar regulation.
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Affiliation(s)
- Yuma Tani
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruaki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshiki Yagi
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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2
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Jin D, Kotar J, Silvester E, Leptos KC, Croze OA. Diurnal Variations in the Motility of Populations of Biflagellate Microalgae. Biophys J 2020; 119:2055-2062. [PMID: 33091375 DOI: 10.1016/j.bpj.2020.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 09/29/2020] [Accepted: 10/07/2020] [Indexed: 10/23/2022] Open
Abstract
The motility of microalgae has been studied extensively, particularly in model microorganisms such as Chlamydomonas reinhardtii. For this and other microalgal species, diurnal cycles are well known to control the metabolism, growth, and cell division. Diurnal variations, however, have been largely neglected in quantitative studies of motility. Here, we demonstrate using tracking microscopy how the motility statistics of C. reinhardtii are modulated by diurnal cycles. With nine independently inoculated cultures synchronized to the light-dark cycle at the exponential growth phase, we repeatedly observed that the mean swimming speed is greater during the dark period of a diurnal cycle. From this measurement, using a hydrodynamic power balance, we infer the mean flagellar beat frequency and conjecture that its diurnal variation reflects modulation of intracellular ATP. Our measurements also quantify the diurnal variations of the orientational and gravitactic transport of C. reinhardtii. We use this to explore the population-level consequences of diurnal variations of motility statistics by evaluating a prediction for how the gravitactic steady state changes with time during a diurnal cycle. Finally, we discuss the consequences of diurnal variations of microalgal motility in soil and pelagic environments.
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Affiliation(s)
- Di Jin
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
| | - Jurij Kotar
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Emma Silvester
- Clarendon Laboratory, University of Oxford, Oxford, United Kingdom
| | - Kyriacos C Leptos
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom
| | - Ottavio A Croze
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
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Maschmann S, Ruban K, Wientapper J, Walter WJ. Phototaxis of the Unicellular Red Alga Cyanidioschyzon merolae Is Mediated by Novel Actin-Driven Tentacles. Int J Mol Sci 2020; 21:E6209. [PMID: 32867346 PMCID: PMC7503314 DOI: 10.3390/ijms21176209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/17/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022] Open
Abstract
Phototaxis, which is the ability to move towards or away from a light source autonomously, is a common mechanism of unicellular algae. It evolved multiple times independently in different plant lineages. As of yet, algal phototaxis has been linked mainly to the presence of cilia, the only known locomotive organelle in unicellular algae. Red algae (Rhodophyta), however, lack cilia in all stages of their life cycle. Remarkably, multiple unicellular red algae like the extremophile Cyanidioschyzon merolae (C. merolae) can move towards light. Remarkably, it has remained unclear how C. merolae achieves movement, and the presence of a completely new mechanism has been suggested. Here we show that the basis of this movement are novel retractable projections, termed tentacles due to their distinct morphology. These tentacles could be reproducibly induced within 20 min by increasing the salt concentration of the culture medium. Electron microscopy revealed filamentous structures inside the tentacles that we identified to be actin filaments. This is surprising as C. merolae's single actin gene was previously published to not be expressed. Based on our findings, we propose a model for C. merolae's actin-driven but myosin-independent motility. To our knowledge, the described tentacles represent a novel motility mechanism.
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Affiliation(s)
| | | | | | - Wilhelm J. Walter
- Institute for Plant Science and Microbiology, University of Hamburg, 20146 Hamburg, Germany; (S.M.); (K.R.); (J.W.)
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Bottier M, Thomas KA, Dutcher SK, Bayly PV. How Does Cilium Length Affect Beating? Biophys J 2019; 116:1292-1304. [PMID: 30878201 PMCID: PMC6451027 DOI: 10.1016/j.bpj.2019.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/23/2019] [Accepted: 02/13/2019] [Indexed: 12/21/2022] Open
Abstract
The effects of cilium length on the dynamics of cilia motion were investigated by high-speed video microscopy of uniciliated mutants of the swimming alga, Chlamydomonas reinhardtii. Cells with short cilia were obtained by deciliating cells via pH shock and allowing cilia to reassemble for limited times. The frequency of cilia beating was estimated from the motion of the cell body and of the cilium. Key features of the ciliary waveform were quantified from polynomial curves fitted to the cilium in each image frame. Most notably, periodic beating did not emerge until the cilium reached a critical length between 2 and 4 μm. Surprisingly, in cells that exhibited periodic beating, the frequency of beating was similar for all lengths with only a slight decrease in frequency as length increased from 4 μm to the normal length of 10-12 μm. The waveform average curvature (rad/μm) was also conserved as the cilium grew. The mechanical metrics of ciliary propulsion (force, torque, and power) all increased in proportion to length. The mechanical efficiency of beating appeared to be maximal at the normal wild-type length of 10-12 μm. These quantitative features of ciliary behavior illuminate the biophysics of cilia motion and, in future studies, may help distinguish competing hypotheses of the underlying mechanism of oscillation.
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Affiliation(s)
- Mathieu Bottier
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri; Department of Genetics, Washington University in St. Louis, St. Louis, Missouri
| | - Kyle A Thomas
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri
| | - Susan K Dutcher
- Department of Genetics, Washington University in St. Louis, St. Louis, Missouri
| | - Philip V Bayly
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri.
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Inner lumen proteins stabilize doublet microtubules in cilia and flagella. Nat Commun 2019; 10:1143. [PMID: 30850601 PMCID: PMC6408466 DOI: 10.1038/s41467-019-09051-x] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 02/10/2019] [Indexed: 12/25/2022] Open
Abstract
Motile cilia are microtubule-based organelles that play important roles in most eukaryotes. Although axonemal microtubules are sufficiently stable to withstand their beating motion, it remains unknown how they are stabilized while serving as tracks for axonemal dyneins. To address this question, we have identified two uncharacterized proteins, FAP45 and FAP52, as microtubule inner proteins (MIPs) in Chlamydomonas. These proteins are conserved among eukaryotes with motile cilia. Using cryo-electron tomography (cryo-ET) and high-speed atomic force microscopy (HS-AFM), we show that lack of these proteins leads to a loss of inner protrusions in B-tubules and less stable microtubules. These protrusions are located near the inner junctions of doublet microtubules and lack of both FAP52 and a known inner junction protein FAP20 results in detachment of the B-tubule from the A-tubule, as well as flagellar shortening. These results demonstrate that FAP45 and FAP52 bind to the inside of microtubules and stabilize ciliary axonemes.
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Biere N, Ghaffar M, Doebbe A, Jäger D, Rothe N, Friedrich BM, Hofestädt R, Schreiber F, Kruse O, Sommer B. Heuristic Modeling and 3D Stereoscopic Visualization of a Chlamydomonas reinhardtii Cell. J Integr Bioinform 2018; 15:/j/jib.2018.15.issue-2/jib-2018-0003/jib-2018-0003.xml. [PMID: 30001212 PMCID: PMC6167046 DOI: 10.1515/jib-2018-0003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/29/2018] [Indexed: 11/15/2022] Open
Abstract
The structural modeling and representation of cells is a complex task as different microscopic, spectroscopic and other information resources have to be combined to achieve a three-dimensional representation with high accuracy. Moreover, to provide an appropriate spatial representation of the cell, a stereoscopic 3D (S3D) visualization is favorable. In this work, a structural cell model is created by combining information from various light microscopic and electron microscopic images as well as from publication-related data. At the mesoscopic level each cell component is presented with special structural and visual properties; at the molecular level a cell membrane composition and the underlying modeling method are discussed; and structural information is correlated with those at the functional level (represented by simplified energy-producing metabolic pathways). The organism used as an example is the unicellular Chlamydomonas reinhardtii, which might be important in future alternative energy production processes. Based on the 3D model, an educative S3D animation was created which was shown at conferences. The complete workflow was accomplished by using the open source 3D modeling software Blender. The discussed project including the animation is available from: http://Cm5.CELLmicrocosmos.org.
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Affiliation(s)
- Niklas Biere
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld, Germany
| | - Mehmood Ghaffar
- Bio-/Medical Informatics Department, Faculty of Technology, Bielefeld University, Bielefeld, Germany
| | - Anja Doebbe
- Algae Biotechnology and Bioenergy, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Daniel Jäger
- Algae Biotechnology and Bioenergy, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Nils Rothe
- Bio-/Medical Informatics Department, Faculty of Technology, Bielefeld University, Bielefeld, Germany
| | - Benjamin M. Friedrich
- Biological Algorithms Group, Center for Advancing Electronics Dresden, Technical University Dresden, Dresden, Germany
| | - Ralf Hofestädt
- Bio-/Medical Informatics Department, Faculty of Technology, Bielefeld University, Bielefeld, Germany
| | - Falk Schreiber
- Computational Life Sciences, Department of Computer and Information Science, University of Konstanz, Konstanz, Germany
- Faculty of Information Technology, Monash University, Melbourne, Australia
| | - Olaf Kruse
- Algae Biotechnology and Bioenergy, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Björn Sommer
- Computational Life Sciences, Department of Computer and Information Science, University of Konstanz, Konstanz, Germany
- Faculty of Information Technology, Monash University, Melbourne, Australia
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Horst NA, Reski R. Microscopy of Physcomitrella patens sperm cells. PLANT METHODS 2017; 13:33. [PMID: 28491120 PMCID: PMC5424408 DOI: 10.1186/s13007-017-0186-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 05/02/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Archegoniates (bryophytes, ferns and gymnosperms), such as the moss Physcomitrella patens, possess freely motile sperm cells (spermatozoids) which reach the egg cell via surface water. Although these motile flagellated sperm cells are a traditional botanical subject, they have not been thoroughly analysed in the flagship non-seed plant model species P. patens. Protocols are required to determine the behaviour of wild type sperms as a prerequisite for future research such as the characterization of mutants or factors that influence sperm number, morphology, viability and motility. RESULTS Here, we present protocols for the observation of fixed, as well as live sperms utilizing a standard microscope at intermediate magnifications. Fixed samples can be used for the fast assessment of sperm number and morphology. To determine functionality, the observation of live sperms is required. Protocols for determining both sperm motility and viability are provided, allowing both parameters to be distinguished. CONCLUSIONS These step-by-step protocols are particularly useful for researchers so far not familiar with the analysis of motile gametes and are meant to aid the establishment and improvement of these analyses in order to stimulate research on spermatogenesis in the moss model species P. patens.
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Affiliation(s)
- Nelly A. Horst
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
- BIOSS – Centre for Biological Signalling Studies, University of Freiburg, Schaenzlestr. 18, 79104 Freiburg, Germany
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