1
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Han Y, Hammerl J, Flemming FE, Schuergers N, Wilde A. A cyanobacterial chemotaxis-like system controls phototactic orientation via phosphorylation of two antagonistic response regulators. MICROLIFE 2024; 5:uqae012. [PMID: 38887653 PMCID: PMC11181946 DOI: 10.1093/femsml/uqae012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 05/14/2024] [Accepted: 05/25/2024] [Indexed: 06/20/2024]
Abstract
Photosynthetic cyanobacteria exhibit phototaxis, utilizing type IV pili (T4P) to navigate either toward or away from a light source. The Tax1 system is a chemotaxis-like signal transduction pathway that controls the switch in cell polarity, which is crucial for positive phototaxis in Synechocystis sp. PCC 6803. The system consists of the blue/green light sensor PixJ, which controls the histidine kinase PixL and two CheY-like response regulators, PixG and PixH. However, the molecular mechanism by which Tax1 regulates T4P activity and polarity is poorly understood. Here, we investigated the phosphotransfer between PixL and its cognate response regulators in vitro and analyzed the localization and function of wild-type and phosphorylation-deficient PixG and PixH during phototaxis. We found that both PixG and PixH are phosphorylated by PixL but have different roles in phototaxis regulation. Only phosphorylated PixG interacts with the T4P motor protein PilB1 and localizes to the leading cell pole under directional light, thereby promoting positive phototaxis. In contrast, PixH is a negative regulator of PixG phosphorylation and inhibits positive phototaxis. We also demonstrated that the C-terminal receiver domain of PixL is essential for positive phototaxis, and modulates the kinase activity of PixL. Our findings reveal the molecular basis of positive phototaxis regulation by the Tax1 system and provide insights into the division of labor between PatA-type and CheY-like response regulators in cyanobacterial chemotaxis-like systems. Furthermore, these findings highlight similarities in the regulation of movement direction during twitching motility in phototactic and chemotactic bacteria.
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Affiliation(s)
- Yu Han
- Molecular Genetics, Institute of Biology III, Schänzlestraße 1, University of Freiburg, 79104 Freiburg, Germany
| | - Jonas Hammerl
- Molecular Genetics, Institute of Biology III, Schänzlestraße 1, University of Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albertstr. 19A, University of Freiburg, Germany
| | - Felicitas E Flemming
- Molecular Genetics, Institute of Biology III, Schänzlestraße 1, University of Freiburg, 79104 Freiburg, Germany
| | - Nils Schuergers
- Molecular Genetics, Institute of Biology III, Schänzlestraße 1, University of Freiburg, 79104 Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics, Institute of Biology III, Schänzlestraße 1, University of Freiburg, 79104 Freiburg, Germany
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2
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Risser DD. Hormogonium Development and Motility in Filamentous Cyanobacteria. Appl Environ Microbiol 2023; 89:e0039223. [PMID: 37199640 PMCID: PMC10304961 DOI: 10.1128/aem.00392-23] [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: 05/19/2023] Open
Abstract
Filamentous cyanobacteria exhibit some of the greatest developmental complexity observed in the prokaryotic domain. This includes the ability to differentiate nitrogen-fixing cells known as heterocysts, spore-like akinetes, and hormogonia, which are specialized motile filaments capable of gliding on solid surfaces. Hormogonia and motility play critical roles in several aspects of the biology of filamentous cyanobacteria, including dispersal, phototaxis, the formation of supracellular structures, and the establishment of nitrogen-fixing symbioses with plants. While heterocyst development has been investigated extensively at the molecular level, much less is known about akinete or hormogonium development and motility. This is due, in part, to the loss of developmental complexity during prolonged laboratory culture in commonly employed model filamentous cyanobacteria. In this review, recent progress in understanding the molecular level regulation of hormogonium development and motility in filamentous cyanobacteria is discussed, with a focus on experiments performed using the genetically tractable model filamentous cyanobacterium Nostoc punctiforme, which retains the developmental complexity of field isolates.
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Affiliation(s)
- Douglas D. Risser
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado, USA
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3
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Song K, Tholen S, Baumgartner D, Schilling O, Hess WR. Isolation of intact and active FoF1 ATP synthase using a FLAG-tagged subunit from the cyanobacterium Synechocystis sp. PCC 6803. STAR Protoc 2022; 3:101623. [PMID: 36039073 PMCID: PMC9418591 DOI: 10.1016/j.xpro.2022.101623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The FoF1 ATP synthase (ATPase) is one of the most important protein complexes in energy metabolism. The isolation of functional ATPase complexes is fundamental to address questions about its assembly, regulation, and functions. This protocol describes the purification of intact and active ATPase from the model cyanobacterium Synechocystis sp. PCC 6803. Basis for purification is a 3×FLAG tag fused to the beta subunit. The ATPase is enzymatically active and its purity is demonstrated using mass spectrometry, denaturing, and blue-native PAGE. For complete details on the use and execution of this protocol, please refer to Song et al. (2022). A triple FLAG tag is fused to the beta subunit of ATP synthase to purify active ATPase Intact ATP synthase can be purified from the model cyanobacterium Synechocystis PAA gels and mass spectrometry can be utilized to assess the purity of the complex The prepared ATP synthase complexes are enzymatically active
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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4
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Koch M, Noonan AJC, Qiu Y, Dofher K, Kieft B, Mottahedeh S, Shastri M, Hallam SJ. The survivor strain: isolation and characterization of Phormidium yuhuli AB48, a filamentous phototactic cyanobacterium with biotechnological potential. Front Bioeng Biotechnol 2022; 10:932695. [PMID: 36046667 PMCID: PMC9420970 DOI: 10.3389/fbioe.2022.932695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Despite their recognized potential, current applications of cyanobacteria as microbial cell factories remain in early stages of development. This is partly due to the fact that engineered strains are often difficult to grow at scale. This technical challenge contrasts with the dense and highly productive cyanobacteria populations thriving in many natural environments. It has been proposed that the selection of strains pre-adapted for growth in industrial photobioreactors could enable more productive cultivation outcomes. Here, we described the initial morphological, physiological, and genomic characterization of Phormidium yuhuli AB48 isolated from an industrial photobioreactor environment. P. yuhuli AB48 is a filamentous phototactic cyanobacterium with a growth rate comparable to Synechocystis sp. PCC 6803. The isolate forms dense biofilms under high salinity and alkaline conditions and manifests a similar nutrient profile to Arthrospira platensis (Spirulina). We sequenced, assembled, and analyzed the P. yuhuli AB48 genome, the first closed circular isolate reference genome for a member of the Phormidium genus. We then used cultivation experiments in combination with proteomics and metabolomics to investigate growth characteristics and phenotypes related to industrial scale cultivation, including nitrogen and carbon utilization, salinity, and pH acclimation, as well as antibiotic resistance. These analyses provide insight into the biological mechanisms behind the desirable growth properties manifested by P. yuhuli AB48 and position it as a promising microbial cell factory for industrial-scale bioproduction[221, 1631].
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Affiliation(s)
- Moritz Koch
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Avery J. C. Noonan
- Genome Science and Technology Program, University of British Columbia, Vancouver, BC, Canada
- ECOSCOPE Training Program, University of British Columbia, Vancouver, BC, Canada
| | - Yilin Qiu
- Genome Science and Technology Program, University of British Columbia, Vancouver, BC, Canada
| | - Kalen Dofher
- Genome Science and Technology Program, University of British Columbia, Vancouver, BC, Canada
| | - Brandon Kieft
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | | | | | - Steven J. Hallam
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Genome Science and Technology Program, University of British Columbia, Vancouver, BC, Canada
- ECOSCOPE Training Program, University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, BC, Canada
- Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Steven J. Hallam,
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5
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Nakane D, Enomoto G, Bähre H, Hirose Y, Wilde A, Nishizaka T. Thermosynechococcus switches the direction of phototaxis by a c-di-GMP-dependent process with high spatial resolution. eLife 2022; 11:73405. [PMID: 35535498 PMCID: PMC9090330 DOI: 10.7554/elife.73405] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Many cyanobacteria, which use light as an energy source via photosynthesis, show directional movement towards or away from a light source. However, the molecular and cell biological mechanisms for switching the direction of movement remain unclear. Here, we visualized type IV pilus-dependent cell movement in the rod-shaped thermophilic cyanobacterium Thermosynechococcus vulcanus using optical microscopy at physiological temperature and light conditions. Positive and negative phototaxis were controlled on a short time scale of 1 min. The cells smoothly moved over solid surfaces towards green light, but the direction was switched to backward movement when we applied additional blue light illumination. The switching was mediated by three photoreceptors, SesA, SesB, and SesC, which have cyanobacteriochrome photosensory domains and synthesis/degradation activity of the bacterial second messenger cyclic dimeric GMP (c-di-GMP). Our results suggest that the decision-making process for directional switching in phototaxis involves light-dependent changes in the cellular concentration of c-di-GMP. Direct visualization of type IV pilus filaments revealed that rod-shaped cells can move perpendicular to the light vector, indicating that the polarity can be controlled not only by pole-to-pole regulation but also within-a-pole regulation. This study provides insights into previously undescribed rapid bacterial polarity regulation via second messenger signalling with high spatial resolution.
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Affiliation(s)
- Daisuke Nakane
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Gen Enomoto
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Heike Bähre
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Yuu Hirose
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi, Japan
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
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6
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A DnaK(Hsp70) Chaperone System Connects Type IV Pilus Activity to Polysaccharide Secretion in Cyanobacteria. mBio 2022; 13:e0051422. [PMID: 35420478 PMCID: PMC9239167 DOI: 10.1128/mbio.00514-22] [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] [Indexed: 11/24/2022] Open
Abstract
Surface motility powered by type IV pili (T4P) is widespread among bacteria, including the photosynthetic cyanobacteria. This form of movement typically requires the deposition of a motility-associated polysaccharide, and several studies indicate that there is complex coregulation of T4P motor activity and polysaccharide production, although a mechanistic understanding of this coregulation is not fully defined. Here, using a combination of genetic, comparative genomic, transcriptomic, protein-protein interaction, and cytological approaches in the model filamentous cyanobacterium N. punctiforme, we provided evidence that a DnaK-type chaperone system coupled the activity of the T4P motors to the production of the motility-associated hormogonium polysaccharide (HPS). The results from these studies indicated that DnaK1 and DnaJ3 along with GrpE comprised a chaperone system that interacted specifically with active T4P motors and was required to produce HPS. Genomic conservation in cyanobacteria and the conservation of the protein-protein interaction network in the model unicellular cyanobacterium Synechocystis sp. strain PCC 6803 imply that this system is conserved among nearly all motile cyanobacteria and provides a mechanism to coordinate polysaccharide secretion and T4P activity in these organisms.
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7
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Lamparter T, Babian J, Fröhlich K, Mielke M, Weber N, Wunsch N, Zais F, Schulz K, Aschmann V, Spohrer N, Krauß N. The involvement of type IV pili and the phytochrome CphA in gliding motility, lateral motility and photophobotaxis of the cyanobacterium Phormidium lacuna. PLoS One 2022; 17:e0249509. [PMID: 35085243 PMCID: PMC8794177 DOI: 10.1371/journal.pone.0249509] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 12/25/2021] [Indexed: 11/29/2022] Open
Abstract
Phormidium lacuna is a naturally competent, filamentous cyanobacterium that belongs to the order Oscillatoriales. The filaments are motile on agar and other surfaces and display rapid lateral movements in liquid culture. Furthermore, they exhibit a photophobotactic response, a phototactic response towards light that is projected vertically onto the area covered by the culture. However, the molecular mechanisms underlying these phenomena are unclear. We performed the first molecular studies on the motility of an Oscillatoriales member. We generated mutants in which a kanamycin resistance cassette (KanR) was integrated in the phytochrome gene cphA and in various genes of the type IV pilin apparatus. pilM, pilN, pilQ and pilT mutants were defective in gliding motility, lateral movements and photophobotaxis, indicating that type IV pili are involved in all three kinds of motility. pilB mutants were only partially blocked in terms of their responses. pilB is the proposed ATPase for expelling of the filament in type IV pili. The genome reveals proteins sharing weak pilB homology in the ATPase region, these might explain the incomplete phenotype. The cphA mutant revealed a significantly reduced photophobotactic response towards red light. Therefore, our results imply that CphA acts as one of several photophobotaxis photoreceptors or that it could modulate the photophobotaxis response.
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Affiliation(s)
- Tilman Lamparter
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
- * E-mail:
| | - Jennifer Babian
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Katrin Fröhlich
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Marion Mielke
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Nora Weber
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Nadja Wunsch
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Finn Zais
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Kevin Schulz
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Vera Aschmann
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Nina Spohrer
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
| | - Norbert Krauß
- Karlsruhe Institute of Technology KIT, Botanical Institute, Karlsruhe, Germany
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8
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Ye Y, Hao H, Xie C. Photomechanical crystalline materials: new developments, property tuning and applications. CrystEngComm 2022. [DOI: 10.1039/d2ce00203e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This highlight gives an overview of the mechanism development, property tuning and application exploration of photomechanical crystalline materials.
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Affiliation(s)
- Yang Ye
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China
| | - Hongxun Hao
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China
- National Collaborative Innovation Center of Chemistry Science and Engineering, Tianjin 300072, China
| | - Chuang Xie
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China
- National Collaborative Innovation Center of Chemistry Science and Engineering, Tianjin 300072, China
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9
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Han Y, Jakob A, Engel S, Wilde A, Nils S. PATAN-domain regulators interact with the Type IV pilus motor to control phototactic orientation in the cyanobacterium Synechocystis. Mol Microbiol 2021; 117:790-801. [PMID: 34936151 DOI: 10.1111/mmi.14872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022]
Abstract
Many prokaryotes show complex behaviors that require the intricate spatial and temporal organization of cellular protein machineries, leading to asymmetrical protein distribution and cell polarity. One such behavior is cyanobacterial phototaxis which relies on the dynamic localization of the Type IV pilus motor proteins in response to light. In the cyanobacterium Synechocystis, various signaling systems encompassing chemotaxis-related CheY- and PatA-like response regulators are critical players in switching between positive and negative phototaxis depending on the light intensity and wavelength. In this study, we show that PatA-type regulators evolved from chemosensory systems. Using fluorescence microscopy and yeast-two-hybrid analysis, we demonstrate that they localize to the inner membrane, where they interact with the N-terminal cytoplasmic domain of PilC and the pilus assembly ATPase PilB1. By separately expressing the subdomains of the response regulator PixE, we confirm that only the N-terminal PATAN domain interacts with PilB1, localizes to the membrane, and is sufficient to reverse phototactic orientation. These experiments established that the PATAN domain is the principal output domain of PatA-type regulators which we presume to modulate pilus extension by binding to the pilus motor components.
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Affiliation(s)
- Yu Han
- Molecular Genetics, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Annik Jakob
- Molecular Genetics, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Sophia Engel
- Molecular Genetics, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Schuergers Nils
- Molecular Genetics, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
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10
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Sugimoto Y, Masuda S. In vivo localization and oligomerization of PixD and PixE for controlling phototaxis in the cyanobacterium Synechocystis sp. PCC 6803. J GEN APPL MICROBIOL 2021; 67:54-58. [PMID: 33342920 DOI: 10.2323/jgam.2020.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Phototaxis is a phenomenon where cyanobacteria move toward a light source. Previous studies have shown that the blue-light-using-flavin (BLUF)-type photoreceptor PixD and the response regulator-like protein PixE control the phototaxis in the cyanobacterium Synechocystis sp. PCC 6803. The pixD-null mutant moves away from light, whereas WT, pixE mutant, and pixD pixE double mutant move toward the light. This indicates that PixE functions downstream of PixD and influences the direction of movement. However, it is still unclear how the light signal received by PixD is transmitted to PixE, and then subsequently transmitted to the type IV pili motor mechanism. Here, we investigated intracellular localization and oligomerization of PixD and PixE to elucidate mechanisms of phototaxis regulation. Blue-native PAGE analysis, coupled with western blotting, indicated that most PixD exist as a dimer in soluble fractions, whereas PixE localized in ~250 kDa and ~450 kDa protein complexes in membrane fractions. When blue-native PAGE was performed after illuminating the membrane fractions with blue light, PixE levels in the ~250 kDa and ~450 kDa complexes were reduced and increased, respectively. These results suggest that PixE, localized in the ~450 kDa complex, controls activity of the motor ATPase PilB1 to regulate pilus motility.
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Affiliation(s)
- Yuki Sugimoto
- Department of Life Science and Technology, Tokyo Institute of Technology
| | - Shinji Masuda
- Department of Life Science and Technology, Tokyo Institute of Technology
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11
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The cyanobacterial taxis protein HmpF regulates type IV pilus activity in response to light. Proc Natl Acad Sci U S A 2021; 118:2023988118. [PMID: 33723073 DOI: 10.1073/pnas.2023988118] [Citation(s) in RCA: 10] [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
Motility is ubiquitous in prokaryotic organisms including the photosynthetic cyanobacteria where surface motility powered by type 4 pili (T4P) is common and facilitates phototaxis to seek out favorable light environments. In cyanobacteria, chemotaxis-like systems are known to regulate motility and phototaxis. The characterized phototaxis systems rely on methyl-accepting chemotaxis proteins containing bilin-binding GAF domains capable of directly sensing light, and the mechanism by which they regulate the T4P is largely undefined. In this study we demonstrate that cyanobacteria possess a second, GAF-independent, means of sensing light to regulate motility and provide insight into how a chemotaxis-like system regulates the T4P motors. A combination of genetic, cytological, and protein-protein interaction analyses, along with experiments using the proton ionophore carbonyl cyanide m-chlorophenyl hydrazine, indicate that the Hmp chemotaxis-like system of the model filamentous cyanobacterium Nostoc punctiforme is capable of sensing light indirectly, possibly via alterations in proton motive force, and modulates direct interaction between the cyanobacterial taxis protein HmpF, and Hfq, PilT1, and PilT2 to regulate the T4P motors. Given that the Hmp system is widely conserved in cyanobacteria, and the finding from this study that orthologs of HmpF and T4P proteins from the distantly related model unicellular cyanobacterium Synechocystis sp. strain PCC6803 interact in a similar manner to their N. punctiforme counterparts, it is likely that this represents a ubiquitous means of regulating motility in response to light in cyanobacteria.
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12
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Conradi FD, Mullineaux CW, Wilde A. The Role of the Cyanobacterial Type IV Pilus Machinery in Finding and Maintaining a Favourable Environment. Life (Basel) 2020; 10:life10110252. [PMID: 33114175 PMCID: PMC7690835 DOI: 10.3390/life10110252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/18/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Type IV pili (T4P) are proteinaceous filaments found on the cell surface of many prokaryotic organisms and convey twitching motility through their extension/retraction cycles, moving cells across surfaces. In cyanobacteria, twitching motility is the sole mode of motility properly characterised to date and is the means by which cells perform phototaxis, the movement towards and away from directional light sources. The wavelength and intensity of the light source determine the direction of movement and, sometimes in concert with nutrient conditions, act as signals for some cyanobacteria to form mucoid multicellular assemblages. Formation of such aggregates or flocs represents an acclimation strategy to unfavourable environmental conditions and stresses, such as harmful light conditions or predation. T4P are also involved in natural transformation by exogenous DNA, secretion processes, and in cellular adaptation and survival strategies, further cementing the role of cell surface appendages. In this way, cyanobacteria are finely tuned by external stimuli to either escape unfavourable environmental conditions via phototaxis, exchange genetic material, and to modify their surroundings to fit their needs by forming multicellular assemblies.
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Affiliation(s)
- Fabian D. Conradi
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (F.D.C.); (C.W.M.)
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (F.D.C.); (C.W.M.)
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Schänzlestr. 1, 79104 Freiburg; Germany
- Correspondence:
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13
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Inago H, Sato R, Masuda S. Regulation of light-induced H + extrusion and uptake by cyanobacterial homologs of the plastidial FLAP1, DLDG1, and Ycf10 in Synechocystis sp. PCC6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148258. [PMID: 32619428 DOI: 10.1016/j.bbabio.2020.148258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 11/29/2022]
Abstract
Upon a dark-to-light transition, multiple species of cyanobacteria release a certain amount of H+ from the inside to the outside of their cells. Previous studies revealed the plasma membrane-localizing Proton exchange A (PxcA) is involved in the light-induced H+ extrusion in the cyanobacterium Synechocystis sp. PCC6803. Among oxygenic phototrophs, two PxcA homologs are conserved; they are the nuclear-encoded Day-length-dependent delayed-greening1 (DLDG1) and the plastid-encoded Ycf10 in Arabidopsis thaliana. We previously identified the putative DLDG1/Ycf10-interacting protein, Fluctuating-light acclimation protein1 (FLAP1), required for pH regulation in Arabidopsis chloroplasts. Synechocystis has PxcA and FLAP1 homologs designated here as PxcA like (PxcL) and FLAP1 homolog A (FlpA). Synechocystis mutants lacking pxcA, pxcL, and flpA were constructed and characterized to gain more insight into regulatory mechanisms of light-induced H+ extrusion in cyanobacteria. pH change kinetics of the extracellular solvent after shifting Synechocystis cells from dark to light indicated that PxcA is essential for the light-induced H+ extrusion, and both PxcA and PxcL were involved in H+ uptake. Mutational loss of flpA resulted in altered PxcA- and PxcL-dependent H+ efflux/influx activities, and the flpA-null mutant showed inhibited growth under dark-light cycles, indicating the importance of FlpA function for photosynthetic growth under fluctuating light. Collectively, these data suggest that PxcA is involved in H+ efflux immediately after light irradiation for the rapid formation of the H+ concentration gradient across the thylakoid membranes, PxcL is involved in H+ influx for activation of the Calvin-Benson-Bassham cycle, and FlpA controls the H+ transport under fluctuating light.
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Affiliation(s)
- Haruya Inago
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Ryoichi Sato
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Shinji Masuda
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
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14
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Chen Z, Li X, Tan X, Zhang Y, Wang B. Recent Advances in Biological Functions of Thick Pili in the Cyanobacterium Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2020; 11:241. [PMID: 32210999 PMCID: PMC7076178 DOI: 10.3389/fpls.2020.00241] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 02/17/2020] [Indexed: 05/05/2023]
Abstract
Cyanobacteria have evolved various strategies to sense and adapt to biotic and abiotic stresses including active movement. Motility in cyanobacteria utilizing the type IV pili (TFP) is useful to cope with changing environmental conditions. The model cyanobacterium Synechocystis sp. PCC 6803 (hereafter named Synechocystis) exhibits motility via TFP called thick pili, and uses it to seek out favorable light/nutrition or escape from unfavorable conditions. Recently, a number of studies on Synechocystis thick pili have been undertaken. Molecular approaches support the role of the pilin in motility, cell adhesion, metal utilization, and natural competence in Synechocystis. This review summarizes the most recent studies on the function of thick pili as well as their formation and regulation in this cyanobacterium.
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Affiliation(s)
- Zhuo Chen
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xitong Li
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xiaoming Tan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Yan Zhang
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
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