1
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Rahman T, Patel S. Recent developments in probing the levels and flux of selected organellar cations as well as organellar mechanosensitivity. Curr Opin Chem Biol 2025; 87:102600. [PMID: 40319567 DOI: 10.1016/j.cbpa.2025.102600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2024] [Revised: 04/01/2025] [Accepted: 04/07/2025] [Indexed: 05/07/2025]
Abstract
Electrochemical gradients exist not only across the plasma membrane (PM) but also across membranes of organelles. Various endomembrane-localised ion channels and transporters have been identified, the activity of which is critical for organellar (and also cellular) ionic homeostasis that underpins diverse cellular processes. Aberrant organellar ion flux underlies several diseases, identifying organellar channels and transporters as potential drug targets. Therefore, the need for probing the functions of these proteins in situ cannot be overemphasised. The acidic interior of a few organelles as well as the dynamic nature of most organelles historically presented challenges for reliable estimation of luminal ionic concentrations. But there have been significant methodological and technical advancements by now, allowing measurement of levels of specific ions within these organelles as well as their flux across endomembranes with increasing precision. Evidence also continues to amass reporting mechanosensitivity of the endomembranes and its physiological significance. Here we highlight some recent developments in tools and techniques for measuring the levels and movement of some selected organellar cations as well as organellar mechanosensitivity.
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Affiliation(s)
- Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
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2
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Lane BJ, Dionysopoulou M, Yan N, Lippiat JD, Muench SP, Pliotas C. The mechanosensitive channel YbiO has a conductance equivalent to the largest gated pore. Structure 2025; 33:652-662.e3. [PMID: 39919733 DOI: 10.1016/j.str.2025.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2024] [Revised: 12/13/2024] [Accepted: 01/13/2025] [Indexed: 02/09/2025]
Abstract
Bacterial mechanosensitive channels are divided into large (MscL) and small (MscS-like) conductance families. The function of MscS and MscL is to protect cells against osmotic shock by acting as pressure safety valves. Within the MscS-like family, E. coli encodes much larger channels, such as YbiO, MscK, and MscM, but their physiological role remains unclear. Compared to MscL their conductances are reported as 3-10 times lower. We show that YbiO can achieve a conductance of ∼3 nS, and an equivalent pore opening of > 25 Å in diameter, equaling the known largest gated pore, MscL. We determine a cryoelectron microscopy (cryo-EM) structure of YbiO in a sub-open conformation, demonstrating the existence of multiple substates. One substate is consistent with the pore opening extent of our structure and the other matches states previously thought to resemble full openings. Our findings demonstrate surprising capabilities, hinting at new physiological roles for YbiO and potentially other MscS-like channels.
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Affiliation(s)
- Benjamin J Lane
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; Aston Institute for Membrane Excellence, Aston University, Birmingham B4 7ET, UK
| | - Mariangela Dionysopoulou
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Nana Yan
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Stephen P Muench
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Christos Pliotas
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK; Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK.
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3
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Chen Q. Regulation of Yeast Cytokinesis by Calcium. J Fungi (Basel) 2025; 11:278. [PMID: 40278099 PMCID: PMC12028594 DOI: 10.3390/jof11040278] [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: 12/28/2024] [Revised: 03/21/2025] [Accepted: 03/22/2025] [Indexed: 04/26/2025] Open
Abstract
The role of calcium, an essential secondary messenger, in cell division remains an outstanding question in cell biology despite several significant findings over the past few decades. Among them is the landmark discovery of intracellular calcium waves during cytokinesis, the last stage of cell division, in fish cells. Nevertheless, subsequent studies have been largely unable to determine the underlying molecular mechanism of these cytokinetic transients. At the center of this stalemate stands two challenging questions, how these calcium transients rise and what they do during cytokinesis. Yeast, despite its proven prowess as a model organism to study cell cycle, has not drawn much interest in addressing these questions. However, the recent discovery of cytokinetic calcium spikes in the fission yeast Schizosaccharomyces pombe has provided novel insights into how calcium regulates cytokinesis. In this review, I will primarily focus on our current understanding of the molecular mechanism of cytokinetic calcium transients in yeast cells. First, I will briefly recount the discovery of cytokinetic calcium transients in animal cells. This will be followed by an introduction to the intracellular calcium homeostasis. Next, I will discuss yeast cytokinetic calcium spikes, the ion channel Pkd2 that promotes these spikes, and the potential molecular targets of these spikes. I will also compare the calcium regulation of cytokinesis between yeast and animal cells. I will conclude by presenting a few critical questions in our continued quest to understand how calcium regulates cytokinesis.
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Affiliation(s)
- Qian Chen
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
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4
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Townson J, Progida C. The emerging roles of the endoplasmic reticulum in mechanosensing and mechanotransduction. J Cell Sci 2025; 138:JCS263503. [PMID: 39976266 DOI: 10.1242/jcs.263503] [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] [Indexed: 02/21/2025] Open
Abstract
Cells are continuously subjected to physical and chemical cues from the extracellular environment, and sense and respond to mechanical cues via mechanosensation and mechanotransduction. Although the role of the cytoskeleton in these processes is well known, the contribution of intracellular membranes has been long neglected. Recently, it has become evident that various organelles play active roles in both mechanosensing and mechanotransduction. In this Review, we focus on mechanosensitive roles of the endoplasmic reticulum (ER), the functions of which are crucial for maintaining cell homeostasis. We discuss the effects of mechanical stimuli on interactions between the ER, the cytoskeleton and other organelles; the role of the ER in intracellular Ca2+ signalling via mechanosensitive channels; and how the unfolded protein response and lipid homeostasis contribute to mechanosensing. The expansive structure of the ER positions it as a key intracellular communication hub, and we additionally explore how this may be leveraged to transduce mechanical signals around the cell. By synthesising current knowledge, we aim to shed light on the emerging roles of the ER in cellular mechanosensing and mechanotransduction.
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Affiliation(s)
- Jonathan Townson
- Department of Biosciences, University of Oslo, Blindernveien 31, 0316 Oslo, Norway
| | - Cinzia Progida
- Department of Biosciences, University of Oslo, Blindernveien 31, 0316 Oslo, Norway
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5
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Lacroix JJ, Wijerathne TD. PIEZO channels as multimodal mechanotransducers. Biochem Soc Trans 2025; 53:BST20240419. [PMID: 39936392 PMCID: PMC12010695 DOI: 10.1042/bst20240419] [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: 10/30/2024] [Revised: 01/09/2025] [Accepted: 01/10/2025] [Indexed: 02/13/2025]
Abstract
All living beings experience a wide range of endogenous and exogenous mechanical forces. The ability to detect these forces and rapidly convert them into specific biological signals is essential to a wide range of physiological processes. In vertebrates, these fundamental tasks are predominantly achieved by two related mechanosensitive ion channels called PIEZO1 and PIEZO2. PIEZO channels are thought to sense mechanical forces through flexible transmembrane blade-like domains. Structural studies indeed show that these mechanosensory domains adopt a curved conformation in a resting membrane but become flattened in a membrane under tension, promoting an open state. Yet, recent studies suggest the intriguing possibility that distinct mechanical stimuli activate PIEZO channels through discrete molecular rearrangements of these domains. In addition, biological signals downstream of PIEZO channel activation vary as a function of the mechanical stimulus and of the cellular context. These unique features could explain how PIEZOs confer cells the ability to differentially interpret a complex landscape of mechanical cues.
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Affiliation(s)
- Jérôme J Lacroix
- Department of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, U.S.A
| | - Tharaka D Wijerathne
- Department of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, U.S.A
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6
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Li K, Jan YN. Experimental tools and emerging principles of organellar mechanotransduction. Trends Cell Biol 2025:S0962-8924(24)00279-4. [PMID: 39828483 DOI: 10.1016/j.tcb.2024.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2024] [Revised: 12/21/2024] [Accepted: 12/24/2024] [Indexed: 01/22/2025]
Abstract
Mechanotransduction is the process by which cells detect mechanical forces and convert them into biochemical or electrical signals. This process occurs across various cellular compartments, including the plasma membrane, cytoskeleton, and intracellular organelles. While research has focused mainly on force sensing at the plasma membrane, the mechanisms and significance of intracellular mechanotransduction are just beginning to be understood. This review summarizes current techniques for studying organellar mechanobiology, and highlights advances in our understanding of the mechanosensitive events occurring in organelles such as the endoplasmic reticulum (ER), Golgi apparatus, and endolysosomes. Additionally, some open questions and promising directions are identified for future research.
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Affiliation(s)
- Kai Li
- Institute for Medical Physiology, Chinese Institutes for Medical Research, Beijing, 100069, China; School of Basic Medicine, Capital Medical University, Beijing, 100069, China
| | - Yuh Nung Jan
- Department of Physiology, University of California at San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA 94158, USA.
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Evangelisti E, Govers F. Roadmap to Success: How Oomycete Plant Pathogens Invade Tissues and Deliver Effectors. Annu Rev Microbiol 2024; 78:493-512. [PMID: 39227351 DOI: 10.1146/annurev-micro-032421-121423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Filamentous plant pathogens threaten global food security and ecosystem resilience. In recent decades, significant strides have been made in deciphering the molecular basis of plant-pathogen interactions, especially the interplay between pathogens' molecular weaponry and hosts' defense machinery. Stemming from interdisciplinary investigations into the infection cell biology of filamentous plant pathogens, recent breakthrough discoveries have provided a new impetus to the field. These advances include the biophysical characterization of a novel invasion mechanism (i.e., naifu invasion) and the unraveling of novel effector secretion routes. On the plant side, progress includes the identification of components of cellular networks involved in the uptake of intracellular effectors. This exciting body of research underscores the pivotal role of logistics management by the pathogen throughout the infection cycle, encompassing the precolonization stages up to tissue invasion. More insight into these logistics opens new avenues for developing environmentally friendly crop protection strategies in an era marked by an imperative to reduce the use of agrochemicals.
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Affiliation(s)
- Edouard Evangelisti
- Current affiliation: Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France;
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, The Netherlands;
| | - Francine Govers
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, The Netherlands;
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8
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Mu B, Rutkowski DM, Grenci G, Vavylonis D, Zhang D. Ca 2+-dependent vesicular and non-vesicular lipid transfer controls hypoosmotic plasma membrane expansion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.20.619261. [PMID: 39484559 PMCID: PMC11527000 DOI: 10.1101/2024.10.20.619261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/03/2024]
Abstract
Robust coordination of surface and volume changes is critical for cell integrity. Few studies have elucidated the plasma membrane (PM) remodeling events during cell surface and volume alteration, especially regarding PM sensing and its subsequent rearrangements. Here, using fission yeast protoplasts, we reveal a Ca2+-dependent mechanism for membrane addition that ensures PM integrity and allows its expansion during acute hypoosmotic cell swelling. We show that MscS-like mechanosensitive channels activated by PM tension control extracellular Ca2+ influx, which triggers direct lipid transfer at endoplasmic reticulum (ER)-PM contact sites by conserved extended-synaptotagmins and accelerates exocytosis, enabling PM expansion necessary for osmotic equilibrium. Defects in any of these key events result in rapid protoplast rupture upon severe hypotonic shock. Our numerical simulations of hypoosmotic expansion further propose a cellular strategy that combines instantaneous non-vesicular lipid transfer with bulk exocytic membrane delivery to maintain PM integrity for dramatic cell surface/volume adaptation.
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Affiliation(s)
- Baicong Mu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604, Singapore
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | | | - Gianluca Grenci
- Mechanobiology Institute (MBI), National University of Singapore, 5A Engineering Drive 1, Singapore 117411
| | | | - Dan Zhang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604, Singapore
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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9
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Li K, Guo Y, Wang Y, Zhu R, Chen W, Cheng T, Zhang X, Jia Y, Liu T, Zhang W, Jan LY, Jan YN. Drosophila TMEM63 and mouse TMEM63A are lysosomal mechanosensory ion channels. Nat Cell Biol 2024; 26:393-403. [PMID: 38388853 PMCID: PMC10940159 DOI: 10.1038/s41556-024-01353-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 01/10/2024] [Indexed: 02/24/2024]
Abstract
Cells sense physical forces and convert them into electrical or chemical signals, a process known as mechanotransduction. Whereas extensive studies focus on mechanotransduction at the plasma membrane, little is known about whether and how intracellular organelles sense mechanical force and the physiological functions of organellar mechanosensing. Here we identify the Drosophila TMEM63 (DmTMEM63) ion channel as an intrinsic mechanosensor of the lysosome, a major degradative organelle. Endogenous DmTMEM63 proteins localize to lysosomes, mediate lysosomal mechanosensitivity and modulate lysosomal morphology and function. Tmem63 mutant flies exhibit impaired lysosomal degradation, synaptic loss, progressive motor deficits and early death, with some of these mutant phenotypes recapitulating symptoms of TMEM63-associated human diseases. Importantly, mouse TMEM63A mediates lysosomal mechanosensitivity in Neuro-2a cells, indicative of functional conservation in mammals. Our findings reveal DmTMEM63 channel function in lysosomes and its physiological roles in vivo and provide a molecular basis to explore the mechanosensitive process in subcellular organelles.
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Affiliation(s)
- Kai Li
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Yanmeng Guo
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Yayu Wang
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Ruijun Zhu
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Wei Chen
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Tong Cheng
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Xiaofan Zhang
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Yinjun Jia
- School of Life Sciences, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, China
| | - Ting Liu
- School of Life Sciences, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, China
| | - Wei Zhang
- School of Life Sciences, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, China
| | - Lily Yeh Jan
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Yuh Nung Jan
- Department of Physiology, University of California at San Francisco, San Francisco, CA, USA.
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA.
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10
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Nakayama Y, Rohde PR, Martinac B. "Force-From-Lipids" Dependence of the MscCG Mechanosensitive Channel Gating on Anionic Membranes. Microorganisms 2023; 11:microorganisms11010194. [PMID: 36677485 PMCID: PMC9861469 DOI: 10.3390/microorganisms11010194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/15/2023] Open
Abstract
Mechanosensory transduction in Corynebacterium glutamicum plays a major role in glutamate efflux for industrial MSG, whose production depends on the activation of MscCG-type mechanosensitive channels. Dependence of the MscCG channel activation by membrane tension on the membrane lipid content has to date not been functionally characterized. Here, we report the MscCG channel patch clamp recording from liposomes fused with C. glutamicum membrane vesicles as well as from proteoliposomes containing the purified MscCG protein. Our recordings demonstrate that mechanosensitivity of MscCG channels depends significantly on the presence of negatively charged lipids in the proteoliposomes. MscCG channels in liposome preparations fused with native membrane vesicles exhibited the activation threshold similar to the channels recorded from C. glutamicum giant spheroplasts. In comparison, the activation threshold of the MscCG channels reconstituted into azolectin liposomes was higher than the activation threshold of E. coli MscL, which is gated by membrane tension close to the bilayer lytic tension. The spheroplast-like activation threshold was restored when the MscCG channels were reconstituted into liposomes made of E. coli polar lipid extract. In liposomes made of polar lipids mixed with synthetic phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin, the activation threshold of MscCG was significantly reduced compared to the activation threshold recorded in azolectin liposomes, which suggests the importance of anionic lipids for the channel mechanosensitivity. Moreover, the micropipette aspiration technique combined with patch fluorometry demonstrated that membranes containing anionic phosphatidylglycerol are softer than membranes containing only polar non-anionic phosphatidylcholine and phosphatidylethanolamine. The difference in mechanosensitivity between C. glutamicum MscCG and canonical MscS of E. coli observed in proteoliposomes explains the evolutionary tuning of the force from lipids sensing in various bacterial membrane environments.
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Affiliation(s)
- Yoshitaka Nakayama
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney 2010, Australia
- Faculty of Medicine, St Vincent’s Clinical School, The University of New South Wales, Sydney 2010, Australia
| | - Paul R. Rohde
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney 2010, Australia
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney 2010, Australia
- Faculty of Medicine, St Vincent’s Clinical School, The University of New South Wales, Sydney 2010, Australia
- Correspondence: ; Tel.: +61-2-9295-8743
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11
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Flegler VJ, Rasmussen T, Böttcher B. How Functional Lipids Affect the Structure and Gating of Mechanosensitive MscS-like Channels. Int J Mol Sci 2022; 23:ijms232315071. [PMID: 36499396 PMCID: PMC9739000 DOI: 10.3390/ijms232315071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/04/2022] Open
Abstract
The ability to cope with and adapt to changes in the environment is essential for all organisms. Osmotic pressure is a universal threat when environmental changes result in an imbalance of osmolytes inside and outside the cell which causes a deviation from the normal turgor. Cells have developed a potent system to deal with this stress in the form of mechanosensitive ion channels. Channel opening releases solutes from the cell and relieves the stress immediately. In bacteria, these channels directly sense the increased membrane tension caused by the enhanced turgor levels upon hypoosmotic shock. The mechanosensitive channel of small conductance, MscS, from Escherichia coli is one of the most extensively studied examples of mechanically stimulated channels. Different conformational states of this channel were obtained in various detergents and membrane mimetics, highlighting an intimate connection between the channel and its lipidic environment. Associated lipids occupy distinct locations and determine the conformational states of MscS. Not all these features are preserved in the larger MscS-like homologues. Recent structures of homologues from bacteria and plants identify common features and differences. This review discusses the current structural and functional models for MscS opening, as well as the influence of certain membrane characteristics on gating.
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12
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Dionysopoulou M, Yan N, Wang B, Pliotas C, Diallinas G. Genetic and cellular characterization of MscS-like putative channels in the filamentous fungus Aspergillus nidulans. Channels (Austin) 2022; 16:148-158. [PMID: 35941834 PMCID: PMC9367656 DOI: 10.1080/19336950.2022.2098661] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mechanosensitive ion channels are integral membrane proteins ubiquitously present in bacteria, archaea, and eukarya. They act as molecular sensors of mechanical stress to serve vital functions such as touch, hearing, osmotic pressure, proprioception and balance, while their malfunction is often associated with pathologies. Amongst them, the structurally distinct MscL and MscS channels from bacteria are the most extensively studied. MscS-like channels have been found in plants and Schizosaccharomyces pombe, where they regulate intracellular Ca2+ and cell volume under hypo-osmotic conditions. Here we characterize two MscS-like putative channels, named MscA and MscB, from the model filamentous fungus Aspergillus nidulans. Orthologues of MscA and MscB are present in most fungi, including relative plant and animal pathogens. MscA/MscB and other fungal MscS-like proteins share the three transmembrane helices and the extended C-terminal cytosolic domain that form the structural fingerprint of MscS-like channels with at least three additional transmembrane segments than Escherichia coli MscS. We show that MscA and MscB localize in Endoplasmic Reticulum and the Plasma Membrane, respectively, whereas their overexpression leads to increased CaCl2 toxicity or/and reduction of asexual spore formation. Our findings contribute to understanding the role of MscS-like channels in filamentous fungi and relative pathogens.
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Affiliation(s)
- Mariangela Dionysopoulou
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, LS2 9JT, Leeds, United Kingdom.,Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15784 Athens, Greece
| | - Nana Yan
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, LS2 9JT, Leeds, United Kingdom
| | - Bolin Wang
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, LS2 9JT, Leeds, United Kingdom
| | - Christos Pliotas
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, LS2 9JT, Leeds, United Kingdom
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15784 Athens, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, 70013 Heraklion, Greece
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Poddar A, Hsu YY, Zhang F, Shamma A, Kreais Z, Muller C, Malla M, Ray A, Liu AP, Chen Q. Membrane stretching activates calcium permeability of a putative channel Pkd2 during fission yeast cytokinesis. Mol Biol Cell 2022; 33:ar134. [PMID: 36200871 PMCID: PMC9727806 DOI: 10.1091/mbc.e22-07-0248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Pkd2 is the fission yeast homologue of polycystins. This putative ion channel localizes to the plasma membrane. It is required for the expansion of cell volume during interphase growth and cytokinesis, the last step of cell division. However, the channel activity of Pkd2 remains untested. Here, we examined the calcium permeability and mechanosensitivity of Pkd2 through in vitro reconstitution and calcium imaging of pkd2 mutant cells. Pkd2 was translated and inserted into the lipid bilayers of giant unilamellar vesicles using a cell-free expression system. The reconstituted Pkd2 permeated calcium when the membrane was stretched via hypoosmotic shock. In vivo, inactivation of Pkd2 through a temperature-sensitive mutation pkd2-B42 reduced the average intracellular calcium level by 34%. Compared with the wild type, the hypomorphic mutation pkd2-81KD reduced the amplitude of hypoosmotic shock-triggered calcium spikes by 59%. During cytokinesis, mutations of pkd2 reduced the calcium spikes, accompanying cell separation and the ensuing membrane stretching, by 60%. We concluded that fission yeast polycystin Pkd2 allows calcium influx when activated by membrane stretching, representing a likely mechanosensitive channel that contributes to the cytokinetic calcium spikes.
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Affiliation(s)
- Abhishek Poddar
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Yen-Yu Hsu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Faith Zhang
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Abeda Shamma
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606
| | - Zachary Kreais
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606
| | - Clare Muller
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Mamata Malla
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Aniruddha Ray
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109,*Address correspondence to: Qian Chen (); Allen Liu ()
| | - Qian Chen
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606,*Address correspondence to: Qian Chen (); Allen Liu ()
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14
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Municio-Diaz C, Muller E, Drevensek S, Fruleux A, Lorenzetti E, Boudaoud A, Minc N. Mechanobiology of the cell wall – insights from tip-growing plant and fungal cells. J Cell Sci 2022; 135:280540. [DOI: 10.1242/jcs.259208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ABSTRACT
The cell wall (CW) is a thin and rigid layer encasing the membrane of all plant and fungal cells. It ensures mechanical integrity by bearing mechanical stresses derived from large cytoplasmic turgor pressure, contacts with growing neighbors or growth within restricted spaces. The CW is made of polysaccharides and proteins, but is dynamic in nature, changing composition and geometry during growth, reproduction or infection. Such continuous and often rapid remodeling entails risks of enhanced stress and consequent damages or fractures, raising the question of how the CW detects and measures surface mechanical stress and how it strengthens to ensure surface integrity? Although early studies in model fungal and plant cells have identified homeostatic pathways required for CW integrity, recent methodologies are now allowing the measurement of pressure and local mechanical properties of CWs in live cells, as well as addressing how forces and stresses can be detected at the CW surface, fostering the emergence of the field of CW mechanobiology. Here, using tip-growing cells of plants and fungi as case study models, we review recent progress on CW mechanosensation and mechanical regulation, and their implications for the control of cell growth, morphogenesis and survival.
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Affiliation(s)
- Celia Municio-Diaz
- Université de Paris, CNRS, Institut Jacques Monod 1 , F-75006 Paris , France
- Equipe Labellisée LIGUE Contre le Cancer 2 , 75013 Paris , France
| | - Elise Muller
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Stéphanie Drevensek
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Antoine Fruleux
- LPTMS, CNRS, Université Paris-Saclay 4 , 91405 Orsay , France
| | - Enrico Lorenzetti
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Arezki Boudaoud
- LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris 3 , 91128 Palaiseau Cedex , France
| | - Nicolas Minc
- Université de Paris, CNRS, Institut Jacques Monod 1 , F-75006 Paris , France
- Equipe Labellisée LIGUE Contre le Cancer 2 , 75013 Paris , France
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15
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Guichard M, Thomine S, Frachisse JM. Mechanotransduction in the spotlight of mechano-sensitive channels. CURRENT OPINION IN PLANT BIOLOGY 2022; 68:102252. [PMID: 35772372 DOI: 10.1016/j.pbi.2022.102252] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/06/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
The study of mechanosensitive channels (MS) in living organisms has progressed considerably over the past two decades. The understanding of their roles in mechanosensation and mechanotransduction was consecrated by the awarding of the Nobel Prize in 2021 to A. Patapoutian for his discoveries on the role of MS channels in mechanoperception in humans. In this review, we first summarize the fundamental properties of MS channels and their mode of operation. Then in a second step, we provide an update on the knowledge on the families of MS channels identified in plants and the roles and functions that have been attributed to them.
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Affiliation(s)
- Marjorie Guichard
- Institute of Cell and Interaction Biology, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Sébastien Thomine
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Jean-Marie Frachisse
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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16
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OzTracs: Optical Osmolality Reporters Engineered from Mechanosensitive Ion Channels. Biomolecules 2022; 12:biom12060787. [PMID: 35740912 PMCID: PMC9221499 DOI: 10.3390/biom12060787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/18/2022] [Accepted: 06/02/2022] [Indexed: 02/01/2023] Open
Abstract
Interactions between physical forces and membrane proteins underpin many forms of environmental sensation and acclimation. Microbes survive osmotic stresses with the help of mechanically gated ion channels and osmolyte transporters. Plant mechanosensitive ion channels have been shown to function in defense signaling. Here, we engineered genetically encoded osmolality sensors (OzTracs) by fusing fluorescent protein spectral variants to the mechanosensitive ion channels MscL from E. coli or MSL10 from A. thaliana. When expressed in yeast cells, the OzTrac sensors reported osmolality changes as a proportional change in the emission ratio of the two fluorescent protein domains. Live-cell imaging revealed an accumulation of fluorescent sensors in internal aggregates, presumably derived from the endomembrane system. Thus, OzTrac sensors serve as osmolality-dependent reporters through an indirect mechanism, such as effects on molecular crowding or fluorophore solvation.
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17
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Cells under pressure: how yeast cells respond to mechanical forces. Trends Microbiol 2022; 30:495-510. [PMID: 35000797 DOI: 10.1016/j.tim.2021.11.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/31/2021] [Accepted: 11/08/2021] [Indexed: 11/23/2022]
Abstract
In their natural habitats, unicellular fungal microbes are exposed to a myriad of mechanical cues such as shear forces from fluid flow, osmotic changes, and contact forces arising from microbial expansion in confined niches. While the rigidity of the cell wall is critical to withstand such external forces and balance high internal turgor pressure, it poses mechanical challenges during physiological processes such as cell growth, division, and mating that require cell wall remodeling. Thus, even organisms as simple as yeast have evolved complex signaling networks to sense and respond to intrinsic and extrinsic mechanical forces. In this review, we summarize the type and origin of mechanical forces experienced by unicellular yeast and discuss how these forces reorganize cell polarity and how pathogenic fungi exploit polarized assemblies to track weak spots in host tissues for successful penetration. We then describe mechanisms of force-sensing by conserved sets of mechanosensors. Finally, we elaborate downstream mechanotransduction mechanisms that orchestrate appropriate cellular responses, leading to improved mechanical fitness.
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18
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MCAs in Arabidopsis are Ca 2+-permeable mechanosensitive channels inherently sensitive to membrane tension. Nat Commun 2021; 12:6074. [PMID: 34667173 PMCID: PMC8526687 DOI: 10.1038/s41467-021-26363-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 10/02/2021] [Indexed: 02/05/2023] Open
Abstract
Mechanosensitive (MS) ion channels respond to mechanical stress and convert it into intracellular electric and ionic signals. Five MS channel families have been identified in plants, including the Mid1-Complementing Activity (MCA) channel; however, its activation mechanisms have not been elucidated in detail. We herein demonstrate that the MCA2 channel is a Ca2+-permeable MS channel that is directly activated by membrane tension. The N-terminal 173 residues of MCA1 and MCA2 were synthesized in vitro, purified, and reconstituted into artificial liposomal membranes. Liposomes reconstituted with MCA1(1-173) or MCA2(1-173) mediate Ca2+ influx and the application of pressure to the membrane reconstituted with MCA2(1-173) elicits channel currents. This channel is also activated by voltage. Blockers for MS channels inhibit activation by stretch, but not by voltage. Since MCA proteins are found exclusively in plants, these results suggest that MCA represent plant-specific MS channels that open directly with membrane tension. Mechanosensitive ion channels convert mechanical stimuli into intracellular electric and ionic signals. Here the authors show that Arabidopsis MCA2 is a Ca2+-permeable mechanosensitive channel that is directly activated by membrane tension.
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19
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Moe-Lange J, Gappel NM, Machado M, Wudick MM, Sies CSA, Schott-Verdugo SN, Bonus M, Mishra S, Hartwig T, Bezrutczyk M, Basu D, Farmer EE, Gohlke H, Malkovskiy A, Haswell ES, Lercher MJ, Ehrhardt DW, Frommer WB, Kleist TJ. Interdependence of a mechanosensitive anion channel and glutamate receptors in distal wound signaling. SCIENCE ADVANCES 2021; 7:eabg4298. [PMID: 34516872 PMCID: PMC8442888 DOI: 10.1126/sciadv.abg4298] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Glutamate has dual roles in metabolism and signaling; thus, signaling functions must be isolatable and distinct from metabolic fluctuations, as seen in low-glutamate domains at synapses. In plants, wounding triggers electrical and calcium (Ca2+) signaling, which involve homologs of mammalian glutamate receptors. The hydraulic dispersal and squeeze-cell hypotheses implicate pressure as a key component of systemic signaling. Here, we identify the stretch-activated anion channel MSL10 as necessary for proper wound-induced electrical and Ca2+ signaling. Wound gene induction, genetics, and Ca2+ imaging indicate that MSL10 acts in the same pathway as the glutamate receptor–like proteins (GLRs). Analogous to mammalian NMDA glutamate receptors, GLRs may serve as coincidence detectors gated by the combined requirement for ligand binding and membrane depolarization, here mediated by stretch activation of MSL10. This study provides a molecular genetic basis for a role of mechanical signal perception and the transmission of long-distance electrical and Ca2+ signals in plants.
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Affiliation(s)
- Jacob Moe-Lange
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Department of Plant Biology, Carnegie Science, Stanford, CA 94305, USA
| | - Nicoline M. Gappel
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Mackenzie Machado
- Department of Plant Biology, Carnegie Science, Stanford, CA 94305, USA
| | - Michael M. Wudick
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Cosima S. A. Sies
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Stephan N. Schott-Verdugo
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Centro de Bioinformática y Simulación Molecular (CBSM), Facultad de Ingeniería, Universidad de Talca, 2 Norte 685, CL-3460000 Talca, Chile
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Bioinformatics), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52425 Jülich, Germany
| | - Michele Bonus
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Swastik Mishra
- Computational Cell Biology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Thomas Hartwig
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Margaret Bezrutczyk
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Debarati Basu
- NSF Center for Engineering Mechanobiology, Department of Biology, Washington University in St. Louis, Box 1137, One Brookings Drive, St. Louis, MO 63130, USA
| | - Edward E. Farmer
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Bioinformatics), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52425 Jülich, Germany
| | - Andrey Malkovskiy
- Department of Plant Biology, Carnegie Science, Stanford, CA 94305, USA
| | - Elizabeth S. Haswell
- NSF Center for Engineering Mechanobiology, Department of Biology, Washington University in St. Louis, Box 1137, One Brookings Drive, St. Louis, MO 63130, USA
| | - Martin J. Lercher
- Computational Cell Biology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - David W. Ehrhardt
- Department of Plant Biology, Carnegie Science, Stanford, CA 94305, USA
| | - Wolf B. Frommer
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8601, Japan
- Corresponding author.
| | - Thomas J. Kleist
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
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20
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Cyclodextrins increase membrane tension and are universal activators of mechanosensitive channels. Proc Natl Acad Sci U S A 2021; 118:2104820118. [PMID: 34475213 DOI: 10.1073/pnas.2104820118] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 07/29/2021] [Indexed: 11/18/2022] Open
Abstract
The bacterial mechanosensitive channel of small conductance (MscS) has been extensively studied to understand how mechanical forces are converted into the conformational changes that underlie mechanosensitive (MS) channel gating. We showed that lipid removal by β-cyclodextrin can mimic membrane tension. Here, we show that all cyclodextrins (CDs) can activate reconstituted Escherichia coli MscS, that MscS activation by CDs depends on CD-mediated lipid removal, and that the CD amount required to gate MscS scales with the channel's sensitivity to membrane tension. Importantly, cholesterol-loaded CDs do not activate MscS. CD-mediated lipid removal ultimately causes MscS desensitization, which we show is affected by the lipid environment. While many MS channels respond to membrane forces, generalized by the "force-from-lipids" principle, their different molecular architectures suggest that they use unique ways to convert mechanical forces into conformational changes. To test whether CDs can also be used to activate other MS channels, we chose to investigate the mechanosensitive channel of large conductance (MscL) and demonstrate that CDs can also activate this structurally unrelated channel. Since CDs can open the least tension-sensitive MS channel, MscL, they should be able to open any MS channel that responds to membrane tension. Thus, CDs emerge as a universal tool for the structural and functional characterization of unrelated MS channels.
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21
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Pivato M, Ballottari M. Chlamydomonas reinhardtii cellular compartments and their contribution to intracellular calcium signalling. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5312-5335. [PMID: 34077536 PMCID: PMC8318260 DOI: 10.1093/jxb/erab212] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/11/2021] [Indexed: 05/12/2023]
Abstract
Calcium (Ca2+)-dependent signalling plays a well-characterized role in the response to different environmental stimuli, in both plant and animal cells. In the model organism for green algae, Chlamydomonas reinhardtii, Ca2+ signals were reported to have a crucial role in different physiological processes, such as stress responses, photosynthesis, and flagella functions. Recent reports identified the underlying components of the Ca2+ signalling machinery at the level of specific subcellular compartments and reported in vivo imaging of cytosolic Ca2+ concentration in response to environmental stimuli. The characterization of these Ca2+-related mechanisms and proteins in C. reinhardtii is providing knowledge on how microalgae can perceive and respond to environmental stimuli, but also on how this Ca2+ signalling machinery has evolved. Here, we review current knowledge on the cellular mechanisms underlying the generation, shaping, and decoding of Ca2+ signals in C. reinhardtii, providing an overview of the known and possible molecular players involved in the Ca2+ signalling of its different subcellular compartments. The advanced toolkits recently developed to measure time-resolved Ca2+ signalling in living C. reinhardtii cells are also discussed, suggesting how they can improve the study of the role of Ca2+ signals in the cellular response of microalgae to environmental stimuli.
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Affiliation(s)
- Matteo Pivato
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Matteo Ballottari
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
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22
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Dave N, Cetiner U, Arroyo D, Fonbuena J, Tiwari M, Barrera P, Lander N, Anishkin A, Sukharev S, Jimenez V. A novel mechanosensitive channel controls osmoregulation, differentiation, and infectivity in Trypanosoma cruzi. eLife 2021; 10:67449. [PMID: 34212856 PMCID: PMC8282336 DOI: 10.7554/elife.67449] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/01/2021] [Indexed: 12/19/2022] Open
Abstract
The causative agent of Chagas disease undergoes drastic morphological and biochemical modifications as it passes between hosts and transitions from extracellular to intracellular stages. The osmotic and mechanical aspects of these cellular transformations are not understood. Here we identify and characterize a novel mechanosensitive channel in Trypanosoma cruzi (TcMscS) belonging to the superfamily of small-conductance mechanosensitive channels (MscS). TcMscS is activated by membrane tension and forms a large pore permeable to anions, cations, and small osmolytes. The channel changes its location from the contractile vacuole complex in epimastigotes to the plasma membrane as the parasites develop into intracellular amastigotes. TcMscS knockout parasites show significant fitness defects, including increased cell volume, calcium dysregulation, impaired differentiation, and a dramatic decrease in infectivity. Our work provides mechanistic insights into components supporting pathogen adaptation inside the host, thus opening the exploration of mechanosensation as a prerequisite for protozoan infectivity.
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Affiliation(s)
- Noopur Dave
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Ugur Cetiner
- Department of Biology, University of Maryland, College Park, United States
| | - Daniel Arroyo
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Joshua Fonbuena
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Megna Tiwari
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Patricia Barrera
- Departmento de Biología, Facultad de Ciencias Exactas y Naturales, Instituto de Histologia y Embriologia IHEM-CONICET, Facultad de Medicina, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Noelia Lander
- Department of Biological Sciences, University of Cincinnati, Cincinnati, United States
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, United States
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, United States
| | - Veronica Jimenez
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
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23
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Squizani ED, Reuwsaat JC, Motta H, Tavanti A, Kmetzsch L. Calcium: a central player in Cryptococcus biology. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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Helliwell KE, Kleiner FH, Hardstaff H, Chrachri A, Gaikwad T, Salmon D, Smirnoff N, Wheeler GL, Brownlee C. Spatiotemporal patterns of intracellular Ca 2+ signalling govern hypo-osmotic stress resilience in marine diatoms. THE NEW PHYTOLOGIST 2021; 230:155-170. [PMID: 33486789 DOI: 10.1111/nph.17162] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 12/11/2020] [Indexed: 05/15/2023]
Abstract
Diatoms are globally important phytoplankton that dominate coastal and polar-ice assemblages. These environments exhibit substantial changes in salinity over dynamic spatiotemporal regimes. Rapid sensory systems are vital to mitigate the harmful consequences of osmotic stress. Population-based analyses have suggested that Ca2+ signalling is involved in diatom osmotic sensing. However, mechanistic insight of the role of osmotic Ca2+ signalling is limited. Here, we show that Phaeodactylum Ca2+ elevations are essential for surviving hypo-osmotic shock. Moreover, employing novel single-cell imaging techniques we have characterised real-time Ca2+ signalling responses in single diatom cells to environmental osmotic perturbations. We observe that intracellular spatiotemporal patterns of osmotic-induced Ca2+ elevations encode vital information regarding the nature of the osmotic stimulus. Localised Ca2+ signals evoked by mild or gradual hypo-osmotic shocks are propagated globally from the apical cell tips, enabling fine-tuned cell volume regulation across the whole cell. Finally, we demonstrate that diatoms adopt Ca2+ -independent and dependent mechanisms for osmoregulation. We find that efflux of organic osmolytes occurs in a Ca2+ -independent manner, but this response is insufficient to mitigate cell damage during hypo-osmotic shock. By comparison, Ca2+ -dependent signalling is necessary to prevent cell bursting via precise coordination of K+ transport, and therefore is likely to underpin survival in dynamic osmotic environments.
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Affiliation(s)
- Katherine E Helliwell
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Friedrich H Kleiner
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - Hayley Hardstaff
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Abdul Chrachri
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Trupti Gaikwad
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Deborah Salmon
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Glen L Wheeler
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Colin Brownlee
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
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25
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Nakayama Y. Corynebacterium glutamicum Mechanosensing: From Osmoregulation to L-Glutamate Secretion for the Avian Microbiota-Gut-Brain Axis. Microorganisms 2021; 9:201. [PMID: 33478007 PMCID: PMC7835871 DOI: 10.3390/microorganisms9010201] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/18/2022] Open
Abstract
After the discovery of Corynebacterium glutamicum from avian feces-contaminated soil, its enigmatic L-glutamate secretion by corynebacterial MscCG-type mechanosensitive channels has been utilized for industrial monosodium glutamate production. Bacterial mechanosensitive channels are activated directly by increased membrane tension upon hypoosmotic downshock; thus; the physiological significance of the corynebacterial L-glutamate secretion has been considered as adjusting turgor pressure by releasing cytoplasmic solutes. In this review, we present information that corynebacterial mechanosensitive channels have been evolutionally specialized as carriers to secrete L-glutamate into the surrounding environment in their habitats rather than osmotic safety valves. The lipid modulation activation of MscCG channels in L-glutamate production can be explained by the "Force-From-Lipids" and "Force-From-Tethers" mechanosensing paradigms and differs significantly from mechanical activation upon hypoosmotic shock. The review also provides information on the search for evidence that C. glutamicum was originally a gut bacterium in the avian host with the aim of understanding the physiological roles of corynebacterial mechanosensing. C. glutamicum is able to secrete L-glutamate by mechanosensitive channels in the gut microbiota and help the host brain function via the microbiota-gut-brain axis.
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Affiliation(s)
- Yoshitaka Nakayama
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; ; Tel.: +61-2-9295-8744
- St Vincent’s Clinical School, Faculty of Medicine, The University of New South Wales, Darlinghurst, NSW 2010, Australia
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26
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Phuyal S, Baschieri F. Endomembranes: Unsung Heroes of Mechanobiology? Front Bioeng Biotechnol 2020; 8:597721. [PMID: 33195167 PMCID: PMC7642594 DOI: 10.3389/fbioe.2020.597721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/05/2020] [Indexed: 12/18/2022] Open
Abstract
Mechanical stimuli have profound effects on the cellular architecture and functions. Over the past two decades, considerable progress has been made in unraveling the molecular machineries that confer cells the ability to sense and transduce mechanical input into biochemical signals. This has resulted in the identification of several force-sensing proteins or mechanically activated ion channels distributed throughout most cell types, whereby the plasma membrane, cytoskeleton, and the nucleus have garnered much attention. Although organelles from the endomembrane system make up significant portion of cell volume and play pivotal roles in the spatiotemporal distribution of signaling molecules, they have received surprisingly little attention in mechanobiology. In this mini-review, we summarize results that document participation of the endomembrane system in sensing and responding to mechanical cues.
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Affiliation(s)
- Santosh Phuyal
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Francesco Baschieri
- Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif, France
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27
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Cox CD, Bavi N, Martinac B. Biophysical Principles of Ion-Channel-Mediated Mechanosensory Transduction. Cell Rep 2020; 29:1-12. [PMID: 31577940 DOI: 10.1016/j.celrep.2019.08.075] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/09/2019] [Accepted: 08/22/2019] [Indexed: 01/12/2023] Open
Abstract
Recent rapid progress in the field of mechanobiology has been driven by novel emerging tools and methodologies and growing interest from different scientific disciplines. Specific progress has been made toward understanding how cell mechanics is linked to intracellular signaling and the regulation of gene expression in response to a variety of mechanical stimuli. There is a direct link between the mechanoreceptors at the cell surface and intracellular biochemical signaling, which in turn controls downstream effector molecules. Among the mechanoreceptors in the cell membrane, mechanosensitive (MS) ion channels are essential for the ultra-rapid (millisecond) transduction of mechanical stimuli into biologically relevant signals. The three decades of research on mechanosensitive channels resulted in the formulation of two basic principles of mechanosensitive channel gating: force-from-lipids and force-from-filament. In this review, we revisit the biophysical principles that underlie the innate force-sensing ability of mechanosensitive channels as contributors to the force-dependent evolution of life forms.
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Affiliation(s)
- Charles D Cox
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Navid Bavi
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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Lee NS, Yoon CW, Wang Q, Moon S, Koo KM, Jung H, Chen R, Jiang L, Lu G, Fernandez A, Chow RH, Weitz AC, Salvaterra PM, Pinaud F, Shung KK. Focused Ultrasound Stimulates ER Localized Mechanosensitive PANNEXIN-1 to Mediate Intracellular Calcium Release in Invasive Cancer Cells. Front Cell Dev Biol 2020; 8:504. [PMID: 32656213 PMCID: PMC7325310 DOI: 10.3389/fcell.2020.00504] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/27/2020] [Indexed: 12/18/2022] Open
Abstract
Focused ultrasound (FUS) is a rapidly developing stimulus technology with the potential to uncover novel mechanosensory dependent cellular processes. Since it is non-invasive, it holds great promise for future therapeutic applications in patients used either alone or as a complement to boost existing treatments. For example, FUS stimulation causes invasive but not non-invasive cancer cell lines to exhibit marked activation of calcium signaling pathways. Here, we identify the membrane channel PANNEXIN1 (PANX1) as a mediator for activation of calcium signaling in invasive cancer cells. Knockdown of PANX1 decreases calcium signaling in invasive cells, while PANX1 overexpression enhances calcium elevations in non-invasive cancer cells. We demonstrate that FUS may directly stimulate mechanosensory PANX1 localized in endoplasmic reticulum to evoke calcium release from internal stores. This process does not depend on mechanosensory stimulus transduction through an intact cytoskeleton and does not depend on plasma membrane localized PANX1. Plasma membrane localized PANX1, however, plays a different role in mediating the spread of intercellular calcium waves via ATP release. Additionally, we show that FUS stimulation evokes cytokine/chemokine release from invasive cancer cells, suggesting that FUS could be an important new adjuvant treatment to improve cancer immunotherapy.
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Affiliation(s)
- Nan Sook Lee
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Chi Woo Yoon
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Qing Wang
- Guangdong Provincial Key Laboratory of Medical Image Processing, School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Sunho Moon
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Kweon Mo Koo
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Hayong Jung
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Ruimin Chen
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Laiming Jiang
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Gengxi Lu
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Antony Fernandez
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Robert H Chow
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, United States
| | - Andrew C Weitz
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Paul M Salvaterra
- Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA, United States
| | - Fabien Pinaud
- Department of Biological Sciences, Chemistry and Physics & Astronomy, University of Southern California, Los Angeles, CA, United States
| | - K Kirk Shung
- Ultrasonic Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
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Characterizing the mechanosensitive response of Paraburkholderia graminis membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183176. [PMID: 31923411 DOI: 10.1016/j.bbamem.2020.183176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 12/10/2019] [Accepted: 01/02/2020] [Indexed: 11/23/2022]
Abstract
Bacterial mechanosensitive channels gate in response to membrane tension, driven by shifts in environmental osmolarity. The mechanosensitive channels of small conductance (MscS) and large conductance (MscL) from Escherichia coli (Ec) gate in response to mechanical force applied to the membrane. Ec-MscS is the foundational member of the MscS superfamily of ion channels, a diverse family with at least fifteen subfamilies identified by homology to the pore lining helix of Ec-MscS, as well as significant diversity on the N- and C-termini. The MscL family of channels are homologous to Ec-MscL. In a rhizosphere associated bacterium, Paraburkholderia graminis C4D1M, mechanosensitive channels are essential for cell survival during changing osmotic environments such as a rainstorm. Utilizing bioinformatics, we predicted six MscS superfamily members and a single MscL homologue. The MscS superfamily members fall into at least three subfamilies: bacterial cyclic nucleotide gated, multi-TM, and extended N-terminus. Osmotic downshock experiments show that wildtype P. graminis cells contain a survival mechanism that prevents cell lysis in response to hypoosmotic shock. To determine if this rescue is due to mechanosensitive channels, we developed a method to create giant spheroplasts of P. graminis to explore the single channel response to applied mechanical tension. Patch clamp electrophysiology on these spheroplasts shows two unique conductances: MscL-like and MscS-like. These conductances are due to likely three unique proteins. This indicates that channels that gate in response to mechanical tension are present in the membrane. Here, we report the first single channel evidence of mechanosensitive ion channels from P. graminis membranes.
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Martinac B, Nikolaev YA, Silvani G, Bavi N, Romanov V, Nakayama Y, Martinac AD, Rohde P, Bavi O, Cox CD. Cell membrane mechanics and mechanosensory transduction. CURRENT TOPICS IN MEMBRANES 2020; 86:83-141. [DOI: 10.1016/bs.ctm.2020.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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A Mechanosensitive Channel Governs Lipid Flippase-Mediated Echinocandin Resistance in Cryptococcus neoformans. mBio 2019; 10:mBio.01952-19. [PMID: 31822582 PMCID: PMC6904872 DOI: 10.1128/mbio.01952-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Echinocandins show fungicidal activity against common invasive mycoses but are ineffective against cryptococcosis. The underlying mechanism for echinocandin resistance in Cryptococcus neoformans remains poorly understood but has been shown to involve Cdc50, the regulatory subunit of lipid flippase. In a forward genetic screen for cdc50Δ suppressor mutations that are caspofungin resistant, we identified Crm1 (caspofungin resistant mutation 1), a homolog of mechanosensitive channel proteins, and showed that crm1Δ restored caspofungin resistance in cdc50Δ cells. Caspofungin-treated cdc50Δ cells exhibited abnormally high intracellular calcium levels ([Ca2+]c) and heightened activation of the calcineurin pathway. Deletion of CRM1 in the cdc50Δ background normalized the abnormally high [Ca2+]c. Cdc50 interacts with Crm1 to maintain cellular calcium homeostasis. Analysis of chitin/chitosan content showed that deleting CRM1 reversed the decreased chitosan production of cdc50Δ cells. Together, these results demonstrate that Cdc50 and Crm1 regulation of the calcineurin pathway and cytoplasmic calcium homeostasis may underlie caspofungin resistance in C. neoformans IMPORTANCE Cryptococcus neoformans is the leading cause of fungal meningitis, accounting for ∼15% of HIV/AIDS-related deaths, but treatment options for cryptococcosis are limited. Echinocandins are the newest fungicidal drug class introduced but are ineffective in treating cryptococcosis. Our previous study identified the lipid flippase subunit Cdc50 as a contributor to echinocandin resistance in C. neoformans Here, we further elucidated the mechanism of Cdc50-mediated caspofungin drug resistance. We discovered that Cdc50 interacts with the mechanosensitive calcium channel protein Crm1 to regulate calcium homeostasis and caspofungin resistance via calcium/calcineurin signaling. These results provide novel insights into echinocandin resistance in this pathogen, which may lead to new treatment options, as well as inform echinocandin resistance mechanisms in other fungal organisms and, hence, advance our understanding of modes of antifungal drug susceptibility and resistance.
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Systematic mapping of cell wall mechanics in the regulation of cell morphogenesis. Proc Natl Acad Sci U S A 2019; 116:13833-13838. [PMID: 31235592 DOI: 10.1073/pnas.1820455116] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Walled cells of plants, fungi, and bacteria come with a large range of shapes and sizes, which are ultimately dictated by the mechanics of their cell wall. This stiff and thin polymeric layer encases the plasma membrane and protects the cells mechanically by opposing large turgor pressure derived mechanical stresses. To date, however, we still lack a quantitative understanding for how local and/or global mechanical properties of the wall support cell morphogenesis. Here, we combine subresolution imaging and laser-mediated wall relaxation to quantitate subcellular values of wall thickness (h) and bulk elastic moduli (Y) in large populations of live mutant cells and in conditions affecting cell diameter in the rod-shaped model fission yeast. We find that lateral wall stiffness, defined by the surface modulus, σ = hY, robustly scales with cell diameter. This scaling is valid across tens of mutants spanning various functions-within the population of individual isogenic strains, along single misshaped cells, and even across the fission yeasts clade. Dynamic modulations of cell diameter by chemical and/or mechanical means suggest that the cell wall can rapidly adapt its surface mechanics, rendering stretched wall portions stiffer than unstretched ones. Size-dependent wall stiffening constrains diameter definition and limits size variations; it may also provide an efficient means to keep elastic strains in the wall below failure strains, potentially promoting cell survival. This quantitative set of data impacts our current understanding of the mechanics of cell walls and its contribution to morphogenesis.
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Nakayama Y, Hashimoto KI, Sawada Y, Sokabe M, Kawasaki H, Martinac B. Corynebacterium glutamicum mechanosensitive channels: towards unpuzzling "glutamate efflux" for amino acid production. Biophys Rev 2018; 10:1359-1369. [PMID: 30209745 PMCID: PMC6233337 DOI: 10.1007/s12551-018-0452-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022] Open
Abstract
Corynebacterium glutamicum has been utilized for industrial amino acid production, especially for monosodium glutamate (MSG), the food-additive for the "UMAMI" category of taste sensation, which is one of the five human basic tastes. Glutamate export from these cells is facilitated by the opening of mechanosensitive channels in the cell membrane within the bacterial cell envelope following specific treatments, such as biotin limitation, addition of Tween 40 or penicillin. A long-unsolved puzzle still remains how and why C. glutamicum mechanosensitive channels are activated by these treatments to export glutamate. Unlike mechanosensitive channels in other bacteria, these channels are not simply osmotic safety valves that prevent these bacteria from bursting upon a hypo-osmotic shock. They also function as metabolic valves to continuously release glutamate as components of a pump-and-leak mechanism regulating the cellular turgor pressure. Recent studies have demonstrated that the opening of the mechanosensitive channel, MscCG, mainly facilitates the efflux of glutamate and not of other amino acids and that the "force-from-lipids" gating mechanism of channels also applies to the MscCG channel. The bacterial types of mechanosensitive channels are found in cell-walled organisms from bacteria to land plants, where their physiological functions have been specialized beyond their basic function in bacterial osmoregulation. In the case of the C. glutamicum MscCG channels, they have evolved to function as specialized glutamate exporters.
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Affiliation(s)
- Yoshitaka Nakayama
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia.
| | - Ken-Ichi Hashimoto
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Yasuyuki Sawada
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Hisashi Kawasaki
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW, 2010, Australia
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Nakayama Y, Komazawa K, Bavi N, Hashimoto KI, Kawasaki H, Martinac B. Evolutionary specialization of MscCG, an MscS-like mechanosensitive channel, in amino acid transport in Corynebacterium glutamicum. Sci Rep 2018; 8:12893. [PMID: 30150671 PMCID: PMC6110860 DOI: 10.1038/s41598-018-31219-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/14/2018] [Indexed: 11/09/2022] Open
Abstract
MscCG, a mechanosensitive channel of Corynebacterium glutamicum provides a major export mechanism for glutamate in this Gram-positive bacterium, which has for many years been used for industrial production of glutamate and other amino acids. The functional characterization of MscCG is therefore, of great significance to understand its conductive properties for different amino acids. Here we report the first successful giant spheroplast preparation of C. glutamicum amenable to the patch clamp technique, which enabled us to investigate mechanosensitive channel activities of MscCG in the native membrane of this bacterium. Single channel recordings from these spheroplasts revealed the presence of three types of mechanosensitive channels, MscCG, MscCG2, and CgMscL, which differ largely from each other in their conductance and mechanosensitivity. MscCG has a relatively small conductance of ~340 pS followed by an intermediate MscCG2 conductance of ~1.0 nS and comparably very large conductance of 3.7 nS exhibited by CgMscL. By applying Laplace's law, we determined that very moderate membrane tension of ~5.5 mN/m was required for half activation of MscCG compared to ~12 mN/m required for half activation of both MscCG2 and CgMscL. Furthermore, by combining the micropipette aspiration technique with molecular dynamics simulations we measured mechanical properties of the C. glutamicum membrane, whose area elasticity module of KA ≈ 15 mN/m is characteristic of a very soft membrane compared to the three times larger area expansion modulus of KA ≈ 44 mN/m of the more elastic E. coli membrane. Moreover, we demonstrate that the "soft" properties of the C. glutamicum membrane have a significant impact on the MscCG gating characterized by a strong voltage-dependent hysteresis in the membrane of C. glutamicum compared to a complete absence of the hysteresis in the E. coli cell membrane. We thus propose that MscCG has evolved and adapted as an MscS-like channel to the mechanical properties of the C. glutamicum membrane enabling the channel to specialize in transport of amino acids such as glutamate, which are major osmolytes helping the bacterial cells survive extreme osmotic stress.
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Affiliation(s)
- Yoshitaka Nakayama
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia
| | - Kosuke Komazawa
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Navid Bavi
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia.,St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Darlinghurst, NSW, 2010, Australia.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Ken-Ichi Hashimoto
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Hisashi Kawasaki
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia. .,St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Darlinghurst, NSW, 2010, Australia.
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Maksaev G, Shoots JM, Ohri S, Haswell ES. Nonpolar residues in the presumptive pore-lining helix of mechanosensitive channel MSL10 influence channel behavior and establish a nonconducting function. PLANT DIRECT 2018; 2:e00059. [PMID: 30506019 PMCID: PMC6261518 DOI: 10.1002/pld3.59] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Mechanosensitive (MS) ion channels provide a universal mechanism for sensing and responding to increased membrane tension. MscS-like (MSL) 10 is a relatively well-studied MS ion channel from Arabidopsis thaliana that is implicated in cell death signaling. The relationship between the amino acid sequence of MSL10 and its conductance, gating tension, and opening and closing kinetics remains unstudied. Here, we identify several nonpolar residues in the presumptive pore-lining transmembrane helix of MSL10 (TM6) that contribute to these basic channel properties. F553 and I554 are essential for wild type channel conductance and the stability of the open state. G556, a glycine residue located at a predicted kink in TM6, is essential for channel conductance. The increased tension sensitivity of MSL10 compared to close homolog MSL8 may be attributed to F563, but other channel characteristics appear to be dictated by more global differences in structure. Finally, MSL10 F553V and MSL10 G556V provided the necessary tools to establish that MSL10's ability to trigger cell death is independent of its ion channel function.
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Affiliation(s)
- Grigory Maksaev
- Department of Biology and Center for Engineering MechanoBiologyWashington University in Saint LouisSaint LouisMissouri
- Present address:
Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability DiseasesWashington University School of MedicineSaint LouisMO
| | - Jennette M. Shoots
- Department of Biology and Center for Engineering MechanoBiologyWashington University in Saint LouisSaint LouisMissouri
| | - Simran Ohri
- Department of Biology and Center for Engineering MechanoBiologyWashington University in Saint LouisSaint LouisMissouri
| | - Elizabeth S. Haswell
- Department of Biology and Center for Engineering MechanoBiologyWashington University in Saint LouisSaint LouisMissouri
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Fletcher J, Griffiths L, Caspari T. Nutrient Limitation Inactivates Mrc1-to-Cds1 Checkpoint Signalling in Schizosaccharomyces pombe. Cells 2018; 7:cells7020015. [PMID: 29473861 PMCID: PMC5850103 DOI: 10.3390/cells7020015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 01/27/2023] Open
Abstract
The S. pombe checkpoint kinase, Cds1, protects the integrity of stalled DNA replication forks after its phosphorylation at threonine-11 by Rad3 (ATR). Modified Cds1 associates through its N-terminal forkhead-associated domain (FHA)-domain with Mrc1 (Claspin) at stalled forks. We report here that nutrient starvation results in post-translational changes to Cds1 and the loss of Mrc1. A drop in glucose after a down-shift from 3% to 0.1–0.3%, or when cells enter the stationary phase, triggers a sharp decline in Mrc1 and the accumulation of insoluble Cds1. Before this transition, Cds1 is transiently activated and phosphorylated by Rad3 when glucose levels fall. Because this coincides with the phosphorylation of histone 2AX at S129 by Rad3, an event that occurs towards the end of every unperturbed S phase, we suggest that a glucose limitation promotes the exit from the S phase. Since nitrogen starvation also depletes Mrc1 while Cds1 is post-translationally modified, we suggest that nutrient limitation is the general signal that promotes exit from S phase before it inactivates the Mrc1–Cds1 signalling component. Why Cds1 accumulates in resting cells while its activator Mrc1 declines is, as yet, unclear but suggests a novel function of Cds1 in non-replicating cells.
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Affiliation(s)
- Jessica Fletcher
- School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK.
- Medical School, Swansea University, Swansea SA2 8PP, UK.
| | - Liam Griffiths
- School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK.
| | - Thomas Caspari
- School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK.
- Postgraduate Doctoral Studies, Paracelsus Medical University, 5020 Salzburg, Austria.
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Abstract
Mechanosensitive (MS) channels protect bacteria against hypo-osmotic shock and fulfil additional functions. Hypo-osmotic shock leads to high turgor pressure that can cause cell rupture and death. MS channels open under these conditions and release unspecifically solutes and consequently the turgor pressure. They can recognise the raised pressure via the increased tension in the cell membrane. Currently, a better understanding how MS channels can sense tension on molecular level is developing because the interaction of the lipid bilayer with the channel is being investigated in detail. The MS channel of large conductance (MscL) and of small conductance (MscS) have been distinguished and studied in molecular detail. In addition, larger channels were found that contain a homologous region corresponding to MscS so that MscS represents a family of channels. Often several members of this family are present in a species. The importance of this family is underlined by the fact that members can be found not only in bacteria but also in higher organisms. While MscL and MscS have been studied for years in particular by electrophysiology, mutagenesis, molecular dynamics, X-ray crystallography and other biophysical techniques, only recently more details are emerging about other members of the MscS-family.
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Abstract
Bacteria represent one of the most evolutionarily successful groups of organisms to inhabit Earth. Their world is awash with mechanical cues, probably the most ancient form of which are osmotic forces. As a result, they have developed highly robust mechanosensors in the form of bacterial mechanosensitive (MS) channels. These channels are essential in osmoregulation, and in this setting, provide one of the simplest paradigms for the study of mechanosensory transduction. We explore the past, present, and future of bacterial MS channels, including the alternate mechanosensory roles that they may play in complex microbial communities. Central to all of these functions is their ability to change conformation in response to mechanical stimuli. We discuss their gating according to the force-from-lipids principle and its applicability to eukaryotic MS channels. This includes the new paradigms emerging for bilayer-mediated channel mechanosensitivity and how this molecular detail may provide advances in both industry and medicine.
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Affiliation(s)
- Charles D Cox
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia; , , .,St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Navid Bavi
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia; , , .,St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia; , , .,St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
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Bickerton P, Sello S, Brownlee C, Pittman JK, Wheeler GL. Spatial and temporal specificity of Ca 2+ signalling in Chlamydomonas reinhardtii in response to osmotic stress. THE NEW PHYTOLOGIST 2016; 212:920-933. [PMID: 27516045 PMCID: PMC5111745 DOI: 10.1111/nph.14128] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/25/2016] [Indexed: 05/06/2023]
Abstract
Ca2+ -dependent signalling processes enable plants to perceive and respond to diverse environmental stressors, such as osmotic stress. A clear understanding of the role of spatiotemporal Ca2+ signalling in green algal lineages is necessary in order to understand how the Ca2+ signalling machinery has evolved in land plants. We used single-cell imaging of Ca2+ -responsive fluorescent dyes in the unicellular green alga Chlamydomonas reinhardtii to examine the specificity of spatial and temporal dynamics of Ca2+ elevations in the cytosol and flagella in response to salinity and osmotic stress. We found that salt stress induced a single Ca2+ elevation that was modulated by the strength of the stimulus and originated in the apex of the cell, spreading as a fast Ca2+ wave. By contrast, hypo-osmotic stress induced a series of repetitive Ca2+ elevations in the cytosol that were spatially uniform. Hypo-osmotic stimuli also induced Ca2+ elevations in the flagella that occurred independently from those in the cytosol. Our results indicate that the requirement for Ca2+ signalling in response to osmotic stress is conserved between land plants and green algae, but the distinct spatial and temporal dynamics of osmotic Ca2+ elevations in C. reinhardtii suggest important mechanistic differences between the two lineages.
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Affiliation(s)
- Peter Bickerton
- Marine Biological AssociationCitadel HillPlymouthPL1 2PBUK
- Faculty of Life SciencesUniversity of ManchesterOxford RoadManchesterM13 9PTUK
| | - Simone Sello
- Marine Biological AssociationCitadel HillPlymouthPL1 2PBUK
- Department of BiologyUniversity of PadovaVia U. Bassi 58/B35131PadovaItaly
| | - Colin Brownlee
- Marine Biological AssociationCitadel HillPlymouthPL1 2PBUK
- School of Ocean and Earth ScienceUniversity of SouthamptonSouthamptonSO14 3ZHUK
| | - Jon K. Pittman
- Faculty of Life SciencesUniversity of ManchesterOxford RoadManchesterM13 9PTUK
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40
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Cox CD, Bavi N, Martinac B. Origin of the Force: The Force-From-Lipids Principle Applied to Piezo Channels. CURRENT TOPICS IN MEMBRANES 2016; 79:59-96. [PMID: 28728824 DOI: 10.1016/bs.ctm.2016.09.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Piezo channels are a ubiquitously expressed, principal type of molecular force sensor in eukaryotes. They enable cells to decode a myriad of physical stimuli and are essential components of numerous mechanosensory processes. Central to their physiological role is the ability to change conformation in response to mechanical force. Here we discuss the evolutionary origin of Piezo in relation to other MS channels in addition to the force that gates Piezo channels. In particular, we discuss whether Piezo channels are inherently mechanosensitive in accordance with the force-from-lipid paradigm which has been firmly established for bacterial MS channels and two-pore domain K+ (K2P) channels. We also discuss the evidence supporting a reliance on or direct interaction with structural scaffold proteins of the cytoskeleton and extracellular matrix according to the force-from-filament principle. In doing so, we explain the false dichotomy that these distinctions represent. We also discuss the possible unifying models that shed light on channel mechanosensitivity at the molecular level.
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Affiliation(s)
- C D Cox
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
| | - N Bavi
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
| | - B Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
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Abstract
Mechanical forces will have been omnipresent since the origin of life, and living organisms have evolved mechanisms to sense, interpret, and respond to mechanical stimuli. The cardiovascular system in general, and the heart in particular, is exposed to constantly changing mechanical signals, including stretch, compression, bending, and shear. The heart adjusts its performance to the mechanical environment, modifying electrical, mechanical, metabolic, and structural properties over a range of time scales. Many of the underlying regulatory processes are encoded intracardially and are, thus, maintained even in heart transplant recipients. Although mechanosensitivity of heart rhythm has been described in the medical literature for over a century, its molecular mechanisms are incompletely understood. Thanks to modern biophysical and molecular technologies, the roles of mechanical forces in cardiac biology are being explored in more detail, and detailed mechanisms of mechanotransduction have started to emerge. Mechano-gated ion channels are cardiac mechanoreceptors. They give rise to mechano-electric feedback, thought to contribute to normal function, disease development, and, potentially, therapeutic interventions. In this review, we focus on acute mechanical effects on cardiac electrophysiology, explore molecular candidates underlying observed responses, and discuss their pharmaceutical regulation. From this, we identify open research questions and highlight emerging technologies that may help in addressing them.
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Affiliation(s)
- Rémi Peyronnet
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.)
| | - Jeanne M Nerbonne
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.)
| | - Peter Kohl
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.).
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42
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Nguyen TTT, Lim YJ, Fan MHM, Jackson RA, Lim KK, Ang WH, Ban KHK, Chen ES. Calcium modulation of doxorubicin cytotoxicity in yeast and human cells. Genes Cells 2016; 21:226-40. [DOI: 10.1111/gtc.12346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/29/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Thi Thuy Trang Nguyen
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- National University Health System; Singapore
| | - Ying Jun Lim
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- National University Health System; Singapore
| | - Melanie Hui Min Fan
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- National University Health System; Singapore
| | - Rebecca A. Jackson
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
| | - Kim Kiat Lim
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- National University Health System; Singapore
| | - Wee Han Ang
- Department of Chemistry; Faculty of Science; National University of Singapore; Singapore
| | - Kenneth Hon Kim Ban
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- National University Health System; Singapore
| | - Ee Sin Chen
- Department of Biochemistry; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
- National University Health System; Singapore
- NUS Graduate School of Science & Engineering; National University of Singapore; Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI); Life Sciences Institute; National University of Singapore; Singapore
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43
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The impact of the C-terminal domain on the gating properties of MscCG from Corynebacterium glutamicum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:130-8. [PMID: 26494188 DOI: 10.1016/j.bbamem.2015.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/14/2015] [Accepted: 10/17/2015] [Indexed: 11/20/2022]
Abstract
The mechanosensitive (MS) channel MscCG from the soil bacterium Corynebacterium glutamicum functions as a major glutamate exporter. MscCG belongs to a subfamily of the bacterial MscS-like channels, which play an important role in osmoregulation. To understand the structural and functional features of MscCG, we investigated the role of the carboxyl-terminal domain, whose relevance for the channel gating has been unknown. The chimeric channel MscS-(C-MscCG), which is a fusion protein between the carboxyl terminal domain of MscCG and the MscS channel, was examined by the patch clamp technique. We found that the chimeric channel exhibited MS channel activity in Escherichia coli spheroplasts characterized by a lower activation threshold and slow closing compared to MscS. The chimeric channel MscS-(C-MscCG) was successfully reconstituted into azolectin liposomes and exhibited gating hysteresis in a voltage-dependent manner, especially at high pipette voltages. Moreover, the channel remained open after releasing pipette pressure at membrane potentials physiologically relevant for C. glutamicum. This contribution to the gating hysteresis of the C-terminal domain of MscCG confers to the channel gating properties highly suitable for release of intracellular solutes.
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44
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Mechanics and morphogenesis of fission yeast cells. Curr Opin Microbiol 2015; 28:36-45. [PMID: 26291501 DOI: 10.1016/j.mib.2015.07.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/15/2015] [Accepted: 07/17/2015] [Indexed: 12/11/2022]
Abstract
The integration of biochemical and biomechanical elements is at the heart of morphogenesis. While animal cells are relatively soft objects which shape and mechanics is mostly regulated by cytoskeletal networks, walled cells including those of plants, fungi and bacteria are encased in a rigid cell wall which resist high internal turgor pressure. How these particular mechanical properties may influence basic cellular processes, such as growth, shape and division remains poorly understood. Recent work using the model fungal cell fission yeast, Schizosaccharomyces pombe, highlights important contribution of cell mechanics to various morphogenesis processes. We envision this genetically tractable system to serve as a novel standard for the mechanobiology of walled cell.
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45
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Rasmussen T, Rasmussen A, Singh S, Galbiati H, Edwards MD, Miller S, Booth IR. Properties of the Mechanosensitive Channel MscS Pore Revealed by Tryptophan Scanning Mutagenesis. Biochemistry 2015; 54:4519-30. [PMID: 26126964 PMCID: PMC4519979 DOI: 10.1021/acs.biochem.5b00294] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Bacterial mechanosensitive channels
gate when the transmembrane
turgor rises to levels that compromise the structural integrity of
the cell wall. Gating creates a transient large diameter pore that
allows hydrated solutes to pass from the cytoplasm at rates close
to those of diffusion. In the closed conformation, the channel limits
transmembrane solute movement, even that of protons. In the MscS crystal
structure (Protein Data Bank entry 2oau), a narrow, hydrophobic opening is visible
in the crystal structure, and it has been proposed that a vapor lock
created by the hydrophobic seals, L105 and L109, is the barrier to
water and ions. Tryptophan scanning mutagenesis has proven to be a
highly valuable tool for the analysis of channel structure. Here Trp
residues were introduced along the pore-forming TM3a helix and in
selected other parts of the protein. Mutants were investigated for
their expression, stability, and activity and as fluorescent probes
of the physical properties along the length of the pore. Most Trp
mutants were expressed at levels similar to that of the parent (MscS
YFF) and were stable as heptamers in detergent in the presence and
absence of urea. Fluorescence data suggest a long hydrophobic region
with low accessibility to aqueous solvents, extending from L105/L109
to G90. Steady-state fluorescence anisotropy data are consistent with
significant homo-Förster resonance energy transfer between
tryptophan residues from different subunits within the narrow pore.
The data provide new insights into MscS structure and gating.
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Affiliation(s)
- Tim Rasmussen
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Akiko Rasmussen
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Shivani Singh
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Heloisa Galbiati
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Michelle D Edwards
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Samantha Miller
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Ian R Booth
- †School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom.,‡Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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46
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Rigamonti M, Groppi S, Belotti F, Ambrosini R, Filippi G, Martegani E, Tisi R. Hypotonic stress-induced calcium signaling in Saccharomyces cerevisiae involves TRP-like transporters on the endoplasmic reticulum membrane. Cell Calcium 2015; 57:57-68. [DOI: 10.1016/j.ceca.2014.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 12/05/2014] [Accepted: 12/06/2014] [Indexed: 11/28/2022]
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47
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Booth IR, Miller S, Müller A, Lehtovirta-Morley L. The evolution of bacterial mechanosensitive channels. Cell Calcium 2014; 57:140-50. [PMID: 25591932 DOI: 10.1016/j.ceca.2014.12.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 12/16/2014] [Accepted: 12/17/2014] [Indexed: 01/17/2023]
Abstract
Mechanosensitive channels are ubiquitous and highly studied. However, the evolution of the bacterial channels remains enigmatic. It can be argued that mechanosensitivity might be a feature of all membrane proteins with some becoming progressively less sensitive to membrane tension over the course of evolution. Bacteria and archaea exhibit two main classes of channels, MscS and MscL. Present day channels suggest that the evolution of MscL may be highly constrained, whereas MscS has undergone elaboration via gene fusion (and potentially gene fission) events to generate a diversity of channel structures. Some of these channel variants are constrained to a small number of genera or species. Some are only found in higher organisms. Only exceptionally have these diverse channels been investigated in any detail. In this review we consider both the processes that might have led to the evolved complexity but also some of the methods exploiting the explosion of genome sequences to understand (and/or track) their distribution. The role of MscS-related channels in calcium-mediated cell biology events is considered.
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Affiliation(s)
- Ian R Booth
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
| | - Samantha Miller
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
| | - Axel Müller
- Division of Chemistry and Chemical Engineering, Broad Institute, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
| | - Laura Lehtovirta-Morley
- Institute of Biological and Environmental Sciences, Cruikshank Building, University of Aberdeen, St Machar Drive, Aberdeen AB24 3UU, UK.
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48
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Hamilton ES, Schlegel AM, Haswell ES. United in diversity: mechanosensitive ion channels in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2014; 66:113-37. [PMID: 25494462 PMCID: PMC4470482 DOI: 10.1146/annurev-arplant-043014-114700] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Mechanosensitive (MS) ion channels are a common mechanism for perceiving and responding to mechanical force. This class of mechanoreceptors is capable of transducing membrane tension directly into ion flux. In plant systems, MS ion channels have been proposed to play a wide array of roles, from the perception of touch and gravity to the osmotic homeostasis of intracellular organelles. Three families of plant MS ion channels have been identified: the MscS-like (MSL), Mid1-complementing activity (MCA), and two-pore potassium (TPK) families. Channels from these families vary widely in structure and function, localize to multiple cellular compartments, and conduct chloride, calcium, and/or potassium ions. However, they are still likely to represent only a fraction of the MS ion channel diversity in plant systems.
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Affiliation(s)
- Eric S. Hamilton
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| | - Angela M. Schlegel
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| | - Elizabeth S. Haswell
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
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49
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Cisneros-Barroso E, Yance-Chávez T, Kito A, Sugiura R, Gómez-Hierro A, Giménez-Zaragoza D, Aligue R. Negative feedback regulation of calcineurin-dependent Prz1 transcription factor by the CaMKK-CaMK1 axis in fission yeast. Nucleic Acids Res 2014; 42:9573-87. [PMID: 25081204 PMCID: PMC4150787 DOI: 10.1093/nar/gku684] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Calcium signals trigger the translocation of the Prz1 transcription factor from the cytoplasm to the nucleus. The process is regulated by the calcium-activated phosphatase calcineurin, which activates Prz1 thereby maintaining active transcription during calcium signalling. When calcium signalling ceases, Prz1 is inactivated by phosphorylation and exported to the cytoplasm. In budding yeast and mammalian cells, different kinases have been reported to counter calcineurin activity and regulate nuclear export. Here, we show that the Ca(2+)/calmodulin-dependent kinase Cmk1 is first phosphorylated and activated by the newly identified kinase CaMKK2 homologue, Ckk2, in response to Ca(2+). Then, active Cmk1 binds, phosphorylates and inactivates Prz1 transcription activity whilst at the same time cmk1 expression is enhanced by Prz1 in response to Ca(2+). Furthermore, Cdc25 phosphatase is also phosphorylated by Cmk1, inducing cell cycle arrest in response to an increase in Ca(2+). Moreover, cmk1 deletion shows a high tolerance to chronic exposure to Ca(2+), due to the lack of cell cycle inhibition and elevated Prz1 activity. This work reveals that Cmk1 kinase activated by the newly identified Ckk2 counteracts calcineurin function by negatively regulating Prz1 activity which in turn is involved in activating cmk1 gene transcription. These results are the first insights into Cmk1 and Ckk2 function in Schizosaccharomyces pombe.
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Affiliation(s)
- Eugenia Cisneros-Barroso
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona 08036, Catalunya, Spain
| | - Tula Yance-Chávez
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona 08036, Catalunya, Spain
| | - Ayako Kito
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka 577-8502, Japan
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka 577-8502, Japan
| | - Alba Gómez-Hierro
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona 08036, Catalunya, Spain
| | - David Giménez-Zaragoza
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona 08036, Catalunya, Spain
| | - Rosa Aligue
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona 08036, Catalunya, Spain
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50
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Nakayama Y, Hirata A, Iida H. Mechanosensitive channels Msy1 and Msy2 are required for maintaining organelle integrity upon hypoosmotic shock in Schizosaccharomyces pombe. FEMS Yeast Res 2014; 14:992-4. [PMID: 25041276 DOI: 10.1111/1567-1364.12181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 11/29/2022] Open
Abstract
The mechanosensitive channels, Mys1 and Msy2, in fission yeast are localized in the endoplasmic reticulum membrane and control cytoplasmic Ca(2+) levels in the hypoosmotic response. We here investigated changes in organellar structures with hypoosmotic shock using transmission electron microscopy. While msy1(-) and msy2(-) single mutant cells developed a number of swollen vacuoles following hypoosmotic shock, similar to wild-type cells, msy1(-) msy2(-) double mutant cells only had two abnormally large vacuoles and cracks between the inner and outer nuclear membranes. These results suggest that Msy1 and Msy2 may be involved in maintaining vacuole integrity and protecting the nuclear envelope upon hypoosmotic shock and also that these two channels are functionally complementary.
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Affiliation(s)
- Yoshitaka Nakayama
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
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