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Kandabashi D, Kawano M, Izutani S, Harada H, Tominaga T, Hori M. HCN channels are essential for the escape response of Paramecium. J Eukaryot Microbiol 2024:e13057. [PMID: 39198998 DOI: 10.1111/jeu.13057] [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: 04/09/2024] [Revised: 08/09/2024] [Accepted: 08/13/2024] [Indexed: 09/01/2024]
Abstract
When mechanical stimulation was applied to free swimming Paramecium, forward swimming velocity transiently increased due to activation of the posterior mechanosensory channels. The behavior response, known as "escape response," requires membrane hyperpolarization and the activation of K-channel type adenylate cyclases. Our hypothesis is that this escape response also involves activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. HCN channels are activated by hyperpolarization and are modulated by cyclic nucleotides such as cAMP and cGMP. They play a critical role in many excitable cells in higher animals. If HCN channels act in Paramecium, this should help to enhance and prolong hyperpolarization, thereby increasing the swimming speed of Paramecium. This study used RNAi to examine the role of the HCN channel 1 in the escape responses by generating hcn1-gene knockdown cells (hcn1-KD). These cells showed reduced mechanically-stimulated escape responses and a lack of cGMP-dependent increases in swimming speed. Electrophysiological experiments demonstrated reduced hyperpolarization upon injection of large negative currents in hcn1-KD cells. This is consistent with a decrease in HCN1 channel activity and changes in the escape response. These findings suggest that HCN1 channels are K+ channels that regulate the escape response of Paramecium by amplifying the hyperpolarizations elicited by posterior mechanical stimulation.
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Affiliation(s)
| | - Mutsumi Kawano
- Faculty of Science, Yamaguchi University, Yamaguchi, Japan
| | | | - Hiyori Harada
- Faculty of Science, Yamaguchi University, Yamaguchi, Japan
| | - Takashi Tominaga
- Institute of Neuroscience, Tokushima Bunri University, Sanuki, Kagawa, Japan
| | - Manabu Hori
- Faculty of Science, Yamaguchi University, Yamaguchi, Japan
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Oshima D, Yoshida M, Saga K, Ito N, Tsuji M, Isu A, Watanabe N, Wakabayashi KI, Yoshimura K. Mechanoresponses mediated by the TRP11 channel in cilia of Chlamydomonas reinhardtii. iScience 2023; 26:107926. [PMID: 37790279 PMCID: PMC10543168 DOI: 10.1016/j.isci.2023.107926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/15/2023] [Accepted: 09/12/2023] [Indexed: 10/05/2023] Open
Abstract
Cilia are organelles involved in motility and sensory transduction, but how these two functions coexist has not been elucidated in depth. Here, the involvement of the ciliary transient receptor potential (TRP) channel TRP11 in mechanoresponses is studied in Chlamydomonas reinhardtii using a TRP11-knockout mutant. The mutant has defects in the conversion of the bending mode of the cilium from forward to reverse when tapped with a glass rod, the detachment of cilia when shear is applied, the increase in ciliary beat frequency upon application of mechanical agitation by vortex mixing, and the initiation of gliding while both cilia are attached in opposite directions to a glass surface. These observations indicate that TRP11 can perceive mechanical stimuli with distinct intensities and durations and induce various types of ciliary responses.
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Affiliation(s)
- Daichi Oshima
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Megumi Yoshida
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Kosuke Saga
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Neo Ito
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Miyu Tsuji
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Atsuko Isu
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Nobuo Watanabe
- Department of Bio-Science and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Ken-ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Department of Industrial Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
| | - Kenjiro Yoshimura
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
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Hori M, Tominaga T, Ishida M, Kawano M. RNA interference reveals the escape response mechanism of Paramecium to mechanical stimulation. Biophys Physicobiol 2023; 20:e200025. [PMID: 37867561 PMCID: PMC10587447 DOI: 10.2142/biophysico.bppb-v20.0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/29/2023] [Indexed: 10/24/2023] Open
Abstract
In Paramecium, a mechanical stimulus applied to the posterior portion of the cell causes a transient increase in membrane permeability to potassium ions, transiently rendering the membrane in a hyperpolarized state. Hyperpolarization causes a transient increase in Cyclic adenosine monophosphate (cAMP) concentration in the cilia, resulting in a transient fast-forward swimming of the cell. Schultz and coworkers (1992) reported that a unique adenylate cyclase (AC)-coupled potassium channel is involved in the reaction underlying this response, which is known as the "escape response." However, the AC responsible for this reaction remains to be identified. Moreover, the molecular linkage between mechanoreception and AC activation has not been elucidated adequately. Currently, we can perform an efficient and simple gene-knockdown technique in Paramecium using RNA interference (RNAi). Paramecium is one of the several model organisms for which whole-genome sequences have been elucidated. The RNAi technique can be applied to whole genome sequences derived from the Paramecium database (ParameciumDB) to investigate the types of proteins that elicit specific biological responses and compare them with those of other model organisms. In this review, we describe the applications of the RNAi technique in elucidating the molecular mechanism underlying the escape response and identifying the AC involved in this reaction. The findings of this study highlight the advantages of the RNAi technique and ParameciumDB.
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Affiliation(s)
- Manabu Hori
- Department of Biology, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan
| | - Takashi Tominaga
- Institute of Neuroscience, Tokushima Bunri University, Sanuki, Kagawa 769-2193, Japan
| | - Masaki Ishida
- School of Science Education, Nara University of Education, Nara 630-8528, Japan
| | - Mutsumi Kawano
- Department of Biology, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan
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