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Eria-Oliveira AS, Folacci M, Chassot AA, Fedou S, Thézé N, Zabelskii D, Alekseev A, Bamberg E, Gordeliy V, Sandoz G, Vivaudou M. Hijacking of internal calcium dynamics by intracellularly residing viral rhodopsins. Nat Commun 2024; 15:65. [PMID: 38167346 PMCID: PMC10761956 DOI: 10.1038/s41467-023-44548-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Rhodopsins are ubiquitous light-driven membrane proteins with diverse functions, including ion transport. Widely distributed, they are also coded in the genomes of giant viruses infecting phytoplankton where their function is not settled. Here, we examine the properties of OLPVR1 (Organic Lake Phycodnavirus Rhodopsin) and two other type 1 viral channelrhodopsins (VCR1s), and demonstrate that VCR1s accumulate exclusively intracellularly, and, upon illumination, induce calcium release from intracellular IP3-dependent stores. In vivo, this light-induced calcium release is sufficient to remote control muscle contraction in VCR1-expressing tadpoles. VCR1s natively confer light-induced Ca2+ release, suggesting a distinct mechanism for reshaping the response to light of virus-infected algae. The ability of VCR1s to photorelease calcium without altering plasma membrane electrical properties marks them as potential precursors for optogenetics tools, with potential applications in basic research and medicine.
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Affiliation(s)
- Ana-Sofia Eria-Oliveira
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
- Université Côte d'Azur, CNRS, INSERM, iBV, Nice, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Nice, France
- Fédération Hospitalo-Universitaire InovPain, Cote d'Azur University, University Hospital Center Nice, Nice, France
| | - Mathilde Folacci
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Nice, France
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Anne Amandine Chassot
- Université Côte d'Azur, CNRS, INSERM, iBV, Nice, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Nice, France
- Fédération Hospitalo-Universitaire InovPain, Cote d'Azur University, University Hospital Center Nice, Nice, France
| | - Sandrine Fedou
- Univ. Bordeaux, Inserm, BRIC, UMR, 1312, Bordeaux, France
| | - Nadine Thézé
- Univ. Bordeaux, Inserm, BRIC, UMR, 1312, Bordeaux, France
| | | | - Alexey Alekseev
- Advanced Optogenes Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Valentin Gordeliy
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
| | - Guillaume Sandoz
- Université Côte d'Azur, CNRS, INSERM, iBV, Nice, France.
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Nice, France.
- Fédération Hospitalo-Universitaire InovPain, Cote d'Azur University, University Hospital Center Nice, Nice, France.
| | - Michel Vivaudou
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France.
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Nice, France.
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2
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Shankar U, Lenka SK, Leigh Ackland M, Callahan DL. Review of the structures and functions of algal photoreceptors to optimize bioproduct production with novel bioreactor designs for strain improvement. Biotechnol Bioeng 2022; 119:2031-2045. [PMID: 35441370 DOI: 10.1002/bit.28116] [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: 11/19/2021] [Revised: 04/15/2022] [Accepted: 04/15/2022] [Indexed: 11/11/2022]
Abstract
Microalgae are important renewable feedstock to produce biodiesel and high-value chemicals. Different wavelengths of light influence the growth and metabolic activities of algae. Recent research has identified the light-sensing proteins called photoreceptors that respond to blue or red light. Structural elucidations of algal photoreceptors have gained momentum over recent years. These include channelrhodopsins, PHOT proteins, animal-like cryptochromes, blue-light sensors utilizing flavin-adenine dinucleotide (BLUF) proteins. Pulsing light has also been investigated as a means to optimize energy inputs into bioreactors. This review summarizes the current structural and functional basis of photoreceptor modulation to optimize the growth, production of carotenoids and other high-value metabolites from microalgae. The review also encompasses novel photobioreactor designs that implement different light regimes including light wavelengths and time to optimize algal growth and desired metabolite profiles for high-value products. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Uttara Shankar
- TERI-Deakin Nanobiotechnology Centre, The Energy and Resources Institute, Gurugram, Haryana, 122001, India.,Deakin University, Geelong, Australia. School of Life and Environmental Sciences, (Burwood Campus), Centre for Cellular and Molecular biology. 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Sangram K Lenka
- TERI-Deakin Nanobiotechnology Centre, The Energy and Resources Institute, Gurugram, Haryana, 122001, India.,Gujarat Biotechnology University, Gandhinagar, Gujarat, 382355, India
| | - M Leigh Ackland
- Deakin University, Geelong, Australia. School of Life and Environmental Sciences, (Burwood Campus), Centre for Cellular and Molecular biology. 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Damien L Callahan
- Deakin University, Geelong, Australia. School of Life and Environmental Sciences, (Burwood Campus), Centre for Cellular and Molecular biology. 221 Burwood Highway, Burwood, VIC, 3125, Australia
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3
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Panzer S, Zhang C, Konte T, Bräuer C, Diemar A, Yogendran P, Yu-Strzelczyk J, Nagel G, Gao S, Terpitz U. Modified Rhodopsins From Aureobasidium pullulans Excel With Very High Proton-Transport Rates. Front Mol Biosci 2021; 8:750528. [PMID: 34790700 PMCID: PMC8591190 DOI: 10.3389/fmolb.2021.750528] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/16/2021] [Indexed: 11/19/2022] Open
Abstract
Aureobasidium pullulans is a black fungus that can adapt to various stressful conditions like hypersaline, acidic, and alkaline environments. The genome of A. pullulans exhibits three genes coding for putative opsins ApOps1, ApOps2, and ApOps3. We heterologously expressed these genes in mammalian cells and Xenopus oocytes. Localization in the plasma membrane was greatly improved by introducing additional membrane trafficking signals at the N-terminus and the C-terminus. In patch-clamp and two-electrode-voltage clamp experiments, all three proteins showed proton pump activity with maximal activity in green light. Among them, ApOps2 exhibited the most pronounced proton pump activity with current amplitudes occasionally extending 10 pA/pF at 0 mV. Proton pump activity was further supported in the presence of extracellular weak organic acids. Furthermore, we used site-directed mutagenesis to reshape protein functions and thereby implemented light-gated proton channels. We discuss the difference to other well-known proton pumps and the potential of these rhodopsins for optogenetic applications.
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Affiliation(s)
- Sabine Panzer
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Chong Zhang
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Tilen Konte
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Ljubljana, Slovenia
| | - Celine Bräuer
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Anne Diemar
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Parathy Yogendran
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Jing Yu-Strzelczyk
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Georg Nagel
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Shiqiang Gao
- Department of Neurophysiology, Physiological Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Julius Maximilian University of Wuerzburg, Wuerzburg, Germany
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Salomé PA, Merchant SS. A Series of Fortunate Events: Introducing Chlamydomonas as a Reference Organism. THE PLANT CELL 2019; 31:1682-1707. [PMID: 31189738 PMCID: PMC6713297 DOI: 10.1105/tpc.18.00952] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 05/20/2019] [Accepted: 06/08/2019] [Indexed: 05/13/2023]
Abstract
The unicellular alga Chlamydomonas reinhardtii is a classical reference organism for studying photosynthesis, chloroplast biology, cell cycle control, and cilia structure and function. It is also an emerging model for studying sensory cilia, the production of high-value bioproducts, and in situ structural determination. Much of the early appeal of Chlamydomonas was rooted in its promise as a genetic system, but like other classic model organisms, this rise to prominence predated the discovery of the structure of DNA, whole-genome sequences, and molecular techniques for gene manipulation. The haploid genome of C. reinhardtii facilitates genetic analyses and offers many of the advantages of microbial systems applied to a photosynthetic organism. C. reinhardtii has contributed to our understanding of chloroplast-based photosynthesis and cilia biology. Despite pervasive transgene silencing, technological advances have allowed researchers to address outstanding lines of inquiry in algal research. The most thoroughly studied unicellular alga, C. reinhardtii, is the current standard for algal research, and although genome editing is still far from efficient and routine, it nevertheless serves as a template for other algae. We present a historical retrospective of the rise of C. reinhardtii to illuminate its past and present. We also present resources for current and future scientists who may wish to expand their studies to the realm of microalgae.
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Affiliation(s)
- Patrice A Salomé
- University of California, Los Angeles, Department of Chemistry and Biochemistry, Los Angeles, CA 90095
| | - Sabeeha S Merchant
- University of California, Los Angeles, Department of Chemistry and Biochemistry, Los Angeles, CA 90095
- University of California, Berkeley, Departments of Plant and Microbial Biology and Molecular and Cell Biology, Berkeley, CA 94720
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5
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Pick U, Zarka A, Boussiba S, Davidi L. A hypothesis about the origin of carotenoid lipid droplets in the green algae Dunaliella and Haematococcus. PLANTA 2019; 249:31-47. [PMID: 30470898 DOI: 10.1007/s00425-018-3050-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/14/2018] [Indexed: 05/20/2023]
Abstract
Hypercarotenogenesis in green algae evolved by mutation of PSY that increased its transcription at high light, disintegration of the eyespot in Dunaliella and acquisition of the capacity to export carotenoids from chloroplasts in Haematococcus. Carotenoids (Car) are lipid-soluble pigments synthesized in plants, algae, bacteria and fungi. Car have strong antioxidative properties and as such are utilized to reduce the danger of different diseases in humans. Two green microalgae are utilized as rich natural sources for Car: Dunaliella salina/bardawil accumulates 10% (w/w) β-carotene (βC), which is also pro-vitamin A, and Haematococcus pluvialis accumulates 4% (w/w) astaxanthin (Ast), the strongest antioxidant among Car. D. bardawil accumulates βC in plastoglobules within the chloroplast, whereas H. pluvialis deposits Ast in cytoplasmic lipid droplets (CLD). In this review we compare the hypercarotenogenic responses (HCR) in Dunaliella and in Haematococcus and try to outline hypothetical evolutionary pathways for its origin. We propose that a mutation in phytoene synthetase that increased its transcription level in response to high light stress had a pivotal role in the evolution of the HCR. Proteomic analyses indicated that in D. bardawil/salina the HCR evolved from dissociation and amplification of eyespot lipid globules. The more robust HCR in algae that accumulate carotenoids in CLD, such as H. pluvialis, required also acquisition of the capacity to export βC out of the chloroplast and its enzymatic conversion into Ast.
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Affiliation(s)
- Uri Pick
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100, Rehovot, Israel.
| | - Aliza Zarka
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, Beer-Sheva, 8499000, Israel
| | - Sammy Boussiba
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, Beer-Sheva, 8499000, Israel
| | - Lital Davidi
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-1569, USA
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6
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Greiner A, Kelterborn S, Evers H, Kreimer G, Sizova I, Hegemann P. Targeting of Photoreceptor Genes in Chlamydomonas reinhardtii via Zinc-Finger Nucleases and CRISPR/Cas9. THE PLANT CELL 2017; 29:2498-2518. [PMID: 28978758 PMCID: PMC5774583 DOI: 10.1105/tpc.17.00659] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/19/2017] [Accepted: 10/04/2017] [Indexed: 05/18/2023]
Abstract
The fast-growing biflagellated single-celled chlorophyte Chlamydomonas reinhardtii is the most widely used alga in basic research. The physiological functions of the 18 sensory photoreceptors are of particular interest with respect to Chlamydomonas development and behavior. Despite the demonstration of gene editing in Chlamydomonas in 1995, the isolation of mutants lacking easily ascertained newly acquired phenotypes remains problematic due to low DNA recombination efficiency. We optimized gene-editing protocols for several Chlamydomonas strains (including wild-type CC-125) using zinc-finger nucleases (ZFNs), genetically encoded CRISPR/associated protein 9 (Cas9) from Staphylococcus aureus and Streptococcus pyogenes, and recombinant Cas9 and developed protocols for rapidly isolating nonselectable gene mutants. Using this technique, we disrupted the photoreceptor genes COP1/2, COP3 (encoding channelrhodopsin 1 [ChR1]), COP4 (encoding ChR2), COP5, PHOT, UVR8, VGCC, MAT3, and aCRY and created the chr1 chr2 and uvr8 phot double mutants. Characterization of the chr1, chr2, and mat3 mutants confirmed the value of photoreceptor mutants for physiological studies. Genes of interest were disrupted in 5 to 15% of preselected clones (∼1 out of 4000 initial cells). Using ZFNs, genes were edited in a reliable, predictable manner via homologous recombination, whereas Cas9 primarily caused gene disruption via the insertion of cotransformed DNA. These methods should be widely applicable to research involving green algae.
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Affiliation(s)
- Andre Greiner
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, 10099 Berlin, Germany
| | - Simon Kelterborn
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, 10099 Berlin, Germany
| | - Heide Evers
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, 10099 Berlin, Germany
| | - Georg Kreimer
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Irina Sizova
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, 10099 Berlin, Germany
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, 10099 Berlin, Germany
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7
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Ahrazem O, Argandoña J, Castillo R, Rubio-Moraga Á, Gómez-Gómez L. Identification and Cloning of Differentially Expressed SOUL and ELIP Genes in Saffron Stigmas Using a Subtractive Hybridization Approach. PLoS One 2016; 11:e0168736. [PMID: 28030614 PMCID: PMC5193429 DOI: 10.1371/journal.pone.0168736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/05/2016] [Indexed: 12/31/2022] Open
Abstract
Using a subtractive hybridization approach, differentially expressed genes involved in the light response in saffron stigmas were identified. Twenty-two differentially expressed transcript-derived fragments were cloned and sequenced. Two of them were highly induced by light and had sequence similarity to early inducible proteins (ELIP) and SOUL heme-binding proteins. Using these sequences, we searched for other family members expressed in saffron stigma. ELIP and SOUL are represented by small gene families in saffron, with four and five members, respectively. The expression of these genes was analyzed during the development of the stigma and in light and dark conditions. ELIP transcripts were detected in all the developmental stages showing much higher expression levels in the developed stigmas of saffron and all were up-regulated by light but at different levels. By contrast, only one SOUL gene was up-regulated by light and was highly expressed in the stigma at anthesis. Both the ELIP and SOUL genes induced by light in saffron stigmas might be associated with the structural changes affecting the chromoplast of the stigma, as a result of light exposure, which promotes the development and increases the number of plastoglobules, specialized in the recruitment of specific proteins, which enables them to act in metabolite synthesis and disposal under changing environmental conditions and developmental stages.
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Affiliation(s)
- Oussama Ahrazem
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Javier Argandoña
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
| | | | - Ángela Rubio-Moraga
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Lourdes Gómez-Gómez
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
- * E-mail:
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8
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Kianianmomeni A, Hallmann A. Algal photoreceptors: in vivo functions and potential applications. PLANTA 2014; 239:1-26. [PMID: 24081482 DOI: 10.1007/s00425-013-1962-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 09/09/2013] [Indexed: 06/02/2023]
Abstract
Many algae, particularly microalgae, possess a sophisticated light-sensing system including photoreceptors and light-modulated signaling pathways to sense environmental information and secure the survival in a rapidly changing environment. Over the last couple of years, the multifaceted world of algal photobiology has enriched our understanding of the light absorption mechanisms and in vivo function of photoreceptors. Moreover, specific light-sensitive modules have already paved the way for the development of optogenetic tools to generate light switches for precise and spatial control of signaling pathways in individual cells and even in complex biological systems.
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Affiliation(s)
- Arash Kianianmomeni
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany,
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9
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Independent localization of plasma membrane and chloroplast components during eyespot assembly. EUKARYOTIC CELL 2013; 12:1258-70. [PMID: 23873865 DOI: 10.1128/ec.00111-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Like many algae, Chlamydomonas reinhardtii is phototactic, using two anterior flagella to swim toward light optimal for photosynthesis. The flagella are responsive to signals initiated at the photosensory eyespot, which comprises photoreceptors in the plasma membrane and layers of pigment granules in the chloroplast. Phototaxis depends on placement of the eyespot at a specific asymmetric location relative to the flagella, basal bodies, and bundles of two or four highly acetylated microtubules, termed rootlets, which extend from the basal bodies toward the posterior of the cell. Previous work has shown that the eyespot is disassembled prior to cell division, and new eyespots are assembled in daughter cells adjacent to the nascent four-membered rootlet associated with the daughter basal body (D4), but the chronology of these assembly events has not been determined. Here we use immunofluorescence microscopy to follow assembly and acetylation of the D4 rootlet, localization of individual eyespot components in the plasma membrane or chloroplast envelope, and flagellar emergence during and immediately following cell division. We find that the D4 rootlet is assembled before the initiation of eyespot assembly, which occurs within the same time frame as rootlet acetylation and flagellar outgrowth. Photoreceptors in the plasma membrane are correctly localized in eyespot mutant cells lacking pigment granule layers, and chloroplast components of the eyespot assemble in mutant cells in which photoreceptor localization is retarded. The data suggest that plasma membrane and chloroplast components of the eyespot are independently responsive to a cytoskeletal positioning cue.
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10
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Schulze T, Schreiber S, Iliev D, Boesger J, Trippens J, Kreimer G, Mittag M. The heme-binding protein SOUL3 of Chlamydomonas reinhardtii influences size and position of the eyespot. MOLECULAR PLANT 2013; 6:931-944. [PMID: 23180671 DOI: 10.1093/mp/sss137] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The flagellated green alga Chlamydomonas reinhardtii has a primitive visual system, the eyespot. It is situated at the cells equator and allows the cell to phototax. In a previous proteomic analysis of the eyespot, the SOUL3 protein was identified among 202 proteins. Here, we investigate the properties and functions of SOUL3. Heterologously expressed SOUL3 is able to bind specifically to hemin. In C. reinhardtii, SOUL3 is expressed at a constant level over the diurnal cycle, but forms protein complexes that differ in size during day and night phases. SOUL3 is primarily localized in the eyespot and it is situated in the pigment globule layer thereof. This is in contrast to the channelrhodopsin photoreceptors, which are localized in the plasma membrane region of the eyespot. Knockdown lines with a significantly reduced SOUL3 level are characterized by mislocalized eyespots, a decreased eyespot size, and alterations in phototactic behavior. Mislocalizations were either anterior or posterior and did not affect association with acetylated microtubules of the daughter four-membered rootlet. Our data suggest that SOUL3 is involved in the organization and placement of the eyespot within the cell.
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Affiliation(s)
- Thomas Schulze
- Institute of General Botany and Plant Physiology, Friedrich Schiller University Jena, 07743 Jena, Germany
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11
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Gunning P. BioArchitecture: the organization and regulation of biological space. BIOARCHITECTURE 2012; 2:200-3. [PMID: 23267413 PMCID: PMC3527313 DOI: 10.4161/bioa.22726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BioArchitecture is a term used to describe the organization and regulation of biological space. It applies to the principles which govern the structure of molecules, polymers and mutiprotein complexes, organelles, membranes and their organization in the cytoplasm and the nucleus. It also covers the integration of cells into their three dimensional environment at the level of cell-matrix, cell-cell interactions, integration into tissue/organ structure and function and finally into the structure of the organism. This review will highlight studies at all these levels which are providing a new way to think about the relationship between the organization of biological space and the function of biological systems.
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Affiliation(s)
- Peter Gunning
- School of Medical Sciences, University of New South Wales, Sydney, Australia.
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12
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Trippens J, Greiner A, Schellwat J, Neukam M, Rottmann T, Lu Y, Kateriya S, Hegemann P, Kreimer G. Phototropin influence on eyespot development and regulation of phototactic behavior in Chlamydomonas reinhardtii. THE PLANT CELL 2012; 24:4687-4702. [PMID: 23204408 PMCID: PMC3531860 DOI: 10.1105/tpc.112.103523] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/21/2012] [Accepted: 11/09/2012] [Indexed: 05/21/2023]
Abstract
The eyespot of Chlamydomonas reinhardtii is a light-sensitive organelle important for phototactic orientation of the alga. Here, we found that eyespot size is strain specific and downregulated in light. In a strain in which the blue light photoreceptor phototropin was deleted by homologous recombination, the light regulation of the eyespot size was affected. We restored this dysfunction in different phototropin complementation experiments. Complementation with the phototropin kinase fragment reduced the eyespot size, independent of light. Interestingly, overexpression of the N-terminal light, oxygen or voltage sensing domains (LOV1+LOV2) alone also affected eyespot size and phototaxis, suggesting that aside from activation of the kinase domain, they fulfill an independent signaling function in the cell. Moreover, phototropin is involved in adjusting the level of channelrhodopsin-1, the dominant primary receptor for phototaxis within the eyespot. Both the level of channelrhodopsin-1 at the onset of illumination and its steady state level during the light period are downregulated by phototropin, whereas the level of channelrhodopsin-2 is not significantly altered. Furthermore, a light intensity-dependent formation of a C-terminal truncated phototropin form was observed. We propose that phototropin is a light regulator of phototaxis that desensitizes the eyespot when blue light intensities increase.
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Affiliation(s)
- Jessica Trippens
- Department of Biology, Friedrich-Alexander-University, 91058 Erlangen, Germany
| | - Andre Greiner
- Institute for Experimental Biophysics, Humboldt University, 10115 Berlin, Germany
| | - Jana Schellwat
- Department of Biology, Friedrich-Alexander-University, 91058 Erlangen, Germany
| | - Martin Neukam
- Department of Biology, Friedrich-Alexander-University, 91058 Erlangen, Germany
| | - Theresa Rottmann
- Department of Biology, Friedrich-Alexander-University, 91058 Erlangen, Germany
| | - Yinghong Lu
- Institute for Experimental Biophysics, Humboldt University, 10115 Berlin, Germany
| | - Suneel Kateriya
- Department of Biochemistry, University of Delhi South Campus, 110021 Delhi, India
| | - Peter Hegemann
- Institute for Experimental Biophysics, Humboldt University, 10115 Berlin, Germany
| | - Georg Kreimer
- Department of Biology, Friedrich-Alexander-University, 91058 Erlangen, Germany
- Erlangen Center of Plant Science, Friedrich-Alexander-University, 91058 Erlangen, Germany
- Address correspondence to
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