1
|
Tutol J, Ong WSY, Phelps SM, Peng W, Goenawan H, Dodani SC. Engineering the ChlorON Series: Turn-On Fluorescent Protein Sensors for Imaging Labile Chloride in Living Cells. ACS CENTRAL SCIENCE 2024; 10:77-86. [PMID: 38292617 PMCID: PMC10823515 DOI: 10.1021/acscentsci.3c01088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/02/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
Beyond its role as the "queen of electrolytes", chloride can also serve as an allosteric regulator or even a signaling ion. To illuminate this essential anion across such a spectrum of biological processes, researchers have relied on fluorescence imaging with genetically encoded sensors. In large part, these have been derived from the green fluorescent protein found in the jellyfish Aequorea victoria. However, a standalone sensor with a turn-on intensiometric response at physiological pH has yet to be reported. Here, we address this technology gap by building on our discovery of the anion-sensitive fluorescent protein mNeonGreen (mNG). The targeted engineering of two non-coordinating residues, namely K143 and R195, in the chloride binding pocket of mNG coupled with an anion walking screening and selection strategy resulted in the ChlorON sensors: ChlorON-1 (K143W/R195L), ChlorON-2 (K143R/R195I), and ChlorON-3 (K143R/R195L). In vitro spectroscopy revealed that all three sensors display a robust turn-on fluorescence response to chloride (20- to 45-fold) across a wide range of affinities (Kd ≈ 30-285 mM). We further showcase how this unique sensing mechanism can be exploited to directly image labile chloride transport with spatial and temporal resolution in a cell model overexpressing the cystic fibrosis transmembrane conductance regulator. Building from this initial demonstration, we anticipate that the ChlorON technology will have broad utility, accelerating the path forward for fundamental and translational aspects of chloride biology.
Collapse
Affiliation(s)
- Jasmine
N. Tutol
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Whitney S. Y. Ong
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Shelby M. Phelps
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Weicheng Peng
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Helen Goenawan
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Sheel C. Dodani
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| |
Collapse
|
2
|
Xu X, Qiu K, Tian Z, Aryal C, Rowan F, Chen R, Sun Y, Diao J. Probing the dynamic crosstalk of lysosomes and mitochondria with structured illumination microscopy. Trends Analyt Chem 2023; 169:117370. [PMID: 37928815 PMCID: PMC10621629 DOI: 10.1016/j.trac.2023.117370] [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] [Indexed: 11/07/2023]
Abstract
Structured illumination microscopy (SIM) is a super-resolution technology for imaging living cells and has been used for studying the dynamics of lysosomes and mitochondria. Recently, new probes and analyzing methods have been developed for SIM imaging, enabling the quantitative analysis of these subcellular structures and their interactions. This review provides an overview of the working principle and advances of SIM, as well as the organelle-targeting principles and types of fluorescence probes, including small molecules, metal complexes, nanoparticles, and fluorescent proteins. Additionally, quantitative methods based on organelle morphology and distribution are outlined. Finally, the review provides an outlook on the current challenges and future directions for improving the combination of SIM imaging and image analysis to further advance the study of organelles. We hope that this review will be useful for researchers working in the field of organelle research and help to facilitate the development of SIM imaging and analysis techniques.
Collapse
Affiliation(s)
- Xiuqiong Xu
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Kangqiang Qiu
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Zhiqi Tian
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Chinta Aryal
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Fiona Rowan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Rui Chen
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Yujie Sun
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| |
Collapse
|
3
|
Petrich A, Aji AK, Dunsing V, Chiantia S. Benchmarking of novel green fluorescent proteins for the quantification of protein oligomerization in living cells. PLoS One 2023; 18:e0285486. [PMID: 37535571 PMCID: PMC10399874 DOI: 10.1371/journal.pone.0285486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/25/2023] [Indexed: 08/05/2023] Open
Abstract
Protein-protein-interactions play an important role in many cellular functions. Quantitative non-invasive techniques are applied in living cells to evaluate such interactions, thereby providing a broader understanding of complex biological processes. Fluorescence fluctuation spectroscopy describes a group of quantitative microscopy approaches for the characterization of molecular interactions at single cell resolution. Through the obtained molecular brightness, it is possible to determine the oligomeric state of proteins. This is usually achieved by fusing fluorescent proteins (FPs) to the protein of interest. Recently, the number of novel green FPs has increased, with consequent improvements to the quality of fluctuation-based measurements. The photophysical behavior of FPs is influenced by multiple factors (including photobleaching, protonation-induced "blinking" and long-lived dark states). Assessing these factors is critical for selecting the appropriate fluorescent tag for live cell imaging applications. In this work, we focus on novel green FPs that are extensively used in live cell imaging. A systematic performance comparison of several green FPs in living cells under different pH conditions using Number & Brightness (N&B) analysis and scanning fluorescence correlation spectroscopy was performed. Our results show that the new FP Gamillus exhibits higher brightness at the cost of lower photostability and fluorescence probability (pf), especially at lower pH. mGreenLantern, on the other hand, thanks to a very high pf, is best suited for multimerization quantification at neutral pH. At lower pH, mEGFP remains apparently the best choice for multimerization investigation. These guidelines provide the information needed to plan quantitative fluorescence microscopy involving these FPs, both for general imaging or for protein-protein-interactions quantification via fluorescence fluctuation-based methods.
Collapse
Affiliation(s)
- Annett Petrich
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Amit Koikkarah Aji
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Valentin Dunsing
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
- Aix-Marseille University, CNRS, UMR 7288, IBDM, Turing Center for Living Systems, Marseille, France
| | - Salvatore Chiantia
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| |
Collapse
|
4
|
Ong WSY, Ji K, Pathiranage V, Maydew C, Baek K, Villones RLE, Meloni G, Walker AR, Dodani SC. Rational Design of the β-Bulge Gate in a Green Fluorescent Protein Accelerates the Kinetics of Sulfate Sensing. Angew Chem Int Ed Engl 2023; 62:e202302304. [PMID: 37059690 PMCID: PMC10330437 DOI: 10.1002/anie.202302304] [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: 02/14/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/16/2023]
Abstract
Detection of anions in complex aqueous media is a fundamental challenge with practical utility that can be addressed by supramolecular chemistry. Biomolecular hosts such as proteins can be used and adapted as an alternative to synthetic hosts. Here, we report how the mutagenesis of the β-bulge residues (D137 and W138) in mNeonGreen, a bright, monomeric fluorescent protein, unlocks and tunes the anion preference at physiological pH for sulfate, resulting in the turn-off sensor SulfOFF-1. This unprecedented sensing arises from an enhancement in the kinetics of binding, largely driven by position 138. In line with these data, molecular dynamics (MD) simulations capture how the coordinated entry and gating of sulfate into the β-barrel is eliminated upon mutagenesis to facilitate binding and fluorescence quenching.
Collapse
Affiliation(s)
- Whitney S. Y. Ong
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| | - Ke Ji
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| | - Vishaka Pathiranage
- Department of Chemistry, Wayne State University, 42 W. Warren Ave. Detroit, MI 48202, USA
| | - Caden Maydew
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| | - Kiheon Baek
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| | - Rhiza Lyne E. Villones
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| | - Alice R. Walker
- Department of Chemistry, Wayne State University, 42 W. Warren Ave. Detroit, MI 48202, USA
| | - Sheel C. Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080-3021, USA
| |
Collapse
|
5
|
Geethakumari AM, Ahmed WS, Rasool S, Fatima A, Nasir Uddin SM, Aouida M, Biswas KH. A genetically encoded BRET-based SARS-CoV-2 M pro protease activity sensor. Commun Chem 2022; 5:117. [PMID: 36187754 PMCID: PMC9516532 DOI: 10.1038/s42004-022-00731-2] [Citation(s) in RCA: 6] [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: 03/03/2022] [Accepted: 09/07/2022] [Indexed: 01/27/2023] Open
Abstract
The main protease, Mpro, is critical for SARS-CoV-2 replication and an appealing target for designing anti-SARS-CoV-2 agents. Therefore, there is a demand for the development of improved sensors to monitor its activity. Here, we report a pair of genetically encoded, bioluminescence resonance energy transfer (BRET)-based sensors for detecting Mpro proteolytic activity in live cells as well as in vitro. The sensors were generated by sandwiching peptides containing the Mpro N-terminal autocleavage sites, either AVLQSGFR (short) or KTSAVLQSGFRKME (long), in between the mNeonGreen and NanoLuc proteins. Co-expression of the sensors with Mpro in live cells resulted in their cleavage while mutation of the critical C145 residue (C145A) in Mpro completely abrogated their cleavage. Additionally, the sensors recapitulated the inhibition of Mpro by the well-characterized pharmacological agent GC376. Further, in vitro assays with the BRET-based Mpro sensors revealed a molecular crowding-mediated increase in the rate of Mpro activity and a decrease in the inhibitory potential of GC376. The sensors developed here will find direct utility in studies related to drug discovery targeting the SARS-CoV-2 Mpro and functional genomics application to determine the effect of sequence variation in Mpro.
Collapse
Affiliation(s)
- Anupriya M. Geethakumari
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Wesam S. Ahmed
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Saad Rasool
- Division of Genomics and Precision Medicine, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Asma Fatima
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - S. M. Nasir Uddin
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Mustapha Aouida
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| | - Kabir H. Biswas
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, 34110 Qatar
| |
Collapse
|
6
|
Galiani S, Reglinski K, Carravilla P, Barbotin A, Urbančič I, Ott J, Sehr J, Sezgin E, Schneider F, Waithe D, Hublitz P, Schliebs W, Erdmann R, Eggeling C. Diffusion and interaction dynamics of the cytosolic peroxisomal import receptor PEX5. BIOPHYSICAL REPORTS 2022; 2:None. [PMID: 36299769 PMCID: PMC9586885 DOI: 10.1016/j.bpr.2022.100055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/24/2022] [Indexed: 11/18/2022]
Abstract
Cellular functions rely on proper actions of organelles such as peroxisomes. These organelles rely on the import of proteins from the cytosol. The peroxisomal import receptor PEX5 takes up target proteins in the cytosol and transports them to the peroxisomal matrix. However, its cytosolic molecular interactions have so far not directly been disclosed. Here, we combined advanced optical microscopy and spectroscopy techniques such as fluorescence correlation spectroscopy and stimulated emission depletion microscopy with biochemical tools to present a detailed characterization of the cytosolic diffusion and interaction dynamics of PEX5. Among other features, we highlight a slow diffusion of PEX5, independent of aggregation or target binding, but associated with cytosolic interaction partners via its N-terminal domain. This sheds new light on the functionality of the receptor in the cytosol as well as highlighting the potential of using complementary microscopy tools to decipher molecular interactions in the cytosol by studying their diffusion dynamics.
Collapse
Affiliation(s)
- S. Galiani
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Wolfson Imaging Centre, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - K. Reglinski
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Leibniz-Institute of Photonic Technologies e.V., Jena, Germany
- Institute of Applied Optic and Biophysics, Friedrich-Schiller University Jena, Jena, Germany
- University Hospital Jena, Jena, Germany
| | - P. Carravilla
- Leibniz-Institute of Photonic Technologies e.V., Jena, Germany
- Institute of Applied Optic and Biophysics, Friedrich-Schiller University Jena, Jena, Germany
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, Spain
| | - A. Barbotin
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - I. Urbančič
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Laboratory of Biophysics, Condensed Matter Physics Department, Jožef Stefan Institute, Ljubljana, Slovenia
| | - J. Ott
- Institute of Biochemistry and Pathobiochemistry, Systems Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - J. Sehr
- Institute of Biochemistry and Pathobiochemistry, Systems Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - E. Sezgin
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, Solna, Sweden
| | - F. Schneider
- Kennedy Institute for Rheumatology, University of Oxford, Oxford, UK
| | - D. Waithe
- Wolfson Imaging Centre, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- WIMM Centre for Computational Biology , MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - P. Hublitz
- WIMM Genome Engineering Services, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - W. Schliebs
- Institute of Biochemistry and Pathobiochemistry, Systems Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - R. Erdmann
- Institute of Biochemistry and Pathobiochemistry, Systems Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - C. Eggeling
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Wolfson Imaging Centre, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Leibniz-Institute of Photonic Technologies e.V., Jena, Germany
- Institute of Applied Optic and Biophysics, Friedrich-Schiller University Jena, Jena, Germany
- Jena Center for Soft Matter (JCSM), Jena, Germany
| |
Collapse
|
7
|
Torres Cabán C, Yang M, Lai C, Yang L, Subach FV, Smith BO, Piatkevich KD, Boyden ES. Tuning the Sensitivity of Genetically Encoded Fluorescent Potassium Indicators through Structure-Guided and Genome Mining Strategies. ACS Sens 2022; 7:1336-1346. [PMID: 35427452 PMCID: PMC9150168 DOI: 10.1021/acssensors.1c02201] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 03/09/2022] [Indexed: 12/31/2022]
Abstract
Genetically encoded potassium indicators lack optimal binding affinity for monitoring intracellular dynamics in mammalian cells. Through structure-guided design and genome mining of potassium binding proteins, we developed green fluorescent potassium indicators with a broad range of binding affinities. KRaION1 (K+ ratiometric indicator for optical imaging based on mNeonGreen 1), based on the insertion of a potassium binding protein, Kbp, from E. coli (Ec-Kbp) into the fluorescent protein mNeonGreen, exhibits an isotonically measured Kd of 69 ± 10 mM (mean ± standard deviation used throughout). We identified Ec-Kbp's binding site using NMR spectroscopy to detect protein-thallium scalar couplings and refined the structure of Ec-Kbp in its potassium-bound state. Guided by this structure, we modified KRaION1, yielding KRaION1/D9N and KRaION2, which exhibit isotonically measured Kd's of 138 ± 21 and 96 ± 9 mM. We identified four Ec-Kbp homologues as potassium binding proteins, which yielded indicators with isotonically measured binding affinities in the 39-112 mM range. KRaIONs functioned in HeLa cells, but the Kd values differed from the isotonically measured case. We found that, by tuning the experimental conditions, Kd values could be obtained that were consistent in vitro and in vivo. We thus recommend characterizing potassium indicator Kd in the physiological context of interest before application.
Collapse
Affiliation(s)
- Cristina
C. Torres Cabán
- McGovern
Institute for Brain Research, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Biological Engineering, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Media Arts & Sciences, MIT, Cambridge, Massachusetts 02139, United States
| | - Minghan Yang
- School
of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
- Westlake
Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China
- Institute
of Basic Medical Sciences, Westlake Institute
for Advanced Study, Hangzhou, Zhejiang 310024, China
- College
of Physics, Jilin University, Changchun, Jilin 130012, China
| | - Cuixin Lai
- School
of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
- Westlake
Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China
- Institute
of Basic Medical Sciences, Westlake Institute
for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Lina Yang
- School
of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
- Westlake
Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China
- Institute
of Basic Medical Sciences, Westlake Institute
for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Fedor V. Subach
- Complex
of NBICS Technologies, National Research
Center “Kurchatov Institute”, Moscow 123182, Russia
| | - Brian O. Smith
- Institute
of Molecular, Cell & Systems Biology, College of Medical Veterinary
& Life Sciences, University of Glasgow, Glasgow G128QQ, United Kingdom
| | - Kiryl D. Piatkevich
- School
of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
- Westlake
Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China
- Institute
of Basic Medical Sciences, Westlake Institute
for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Edward S. Boyden
- McGovern
Institute for Brain Research, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Biological Engineering, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Media Arts & Sciences, MIT, Cambridge, Massachusetts 02139, United States
- Koch
Institute for Integrative Cancer Research, MIT, Cambridge, Massachusetts 02139, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, United States
- Department
of Brain and Cognitive Sciences, MIT, Cambridge, Massachusetts 02139, United States
- K.
Lisa Yang Center for Bionics, MIT, Cambridge, Massachusetts 02139, United States
- Center
for Neurobiological Engineering, MIT, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
8
|
Mukherjee S, Jimenez R. Photophysical Engineering of Fluorescent Proteins: Accomplishments and Challenges of Physical Chemistry Strategies. J Phys Chem B 2022; 126:735-750. [DOI: 10.1021/acs.jpcb.1c05629] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Srijit Mukherjee
- JILA, University of Colorado at Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado at Boulder, 215 UCB, Boulder, Colorado 80309, United States
| | - Ralph Jimenez
- JILA, University of Colorado at Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado at Boulder, 215 UCB, Boulder, Colorado 80309, United States
| |
Collapse
|
9
|
Fricke PM, Lürkens M, Hünnefeld M, Sonntag CK, Bott M, Davari MD, Polen T. Highly tunable TetR-dependent target gene expression in the acetic acid bacterium Gluconobacter oxydans. Appl Microbiol Biotechnol 2021; 105:6835-6852. [PMID: 34448898 PMCID: PMC8426231 DOI: 10.1007/s00253-021-11473-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 11/27/2022]
Abstract
Abstract For the acetic acid bacterium (AAB) Gluconobacter oxydans only recently the first tight system for regulatable target gene expression became available based on the heterologous repressor-activator protein AraC from Escherichia coli and the target promoter ParaBAD. In this study, we tested pure repressor-based TetR- and LacI-dependent target gene expression in G. oxydans by applying the same plasmid backbone and construction principles that we have used successfully for the araC-ParaBAD system. When using a pBBR1MCS-5-based plasmid, the non-induced basal expression of the Tn10-based TetR-dependent expression system was extremely low. This allowed calculated induction ratios of up to more than 3500-fold with the fluorescence reporter protein mNeonGreen (mNG). The induction was highly homogeneous and tunable by varying the anhydrotetracycline concentration from 10 to 200 ng/mL. The already strong reporter gene expression could be doubled by inserting the ribosome binding site AGGAGA into the 3’ region of the Ptet sequence upstream from mNG. Alternative plasmid constructs used as controls revealed a strong influence of transcription terminators and antibiotics resistance gene of the plasmid backbone on the resulting expression performance. In contrast to the TetR-Ptet-system, pBBR1MCS-5-based LacI-dependent expression from PlacUV5 always exhibited some non-induced basal reporter expression and was therefore tunable only up to 40-fold induction by IPTG. The leakiness of PlacUV5 when not induced was independent of potential read-through from the lacI promoter. Protein-DNA binding simulations for pH 7, 6, 5, and 4 by computational modeling of LacI, TetR, and AraC with DNA suggested a decreased DNA binding of LacI when pH is below 6, the latter possibly causing the leakiness of LacI-dependent systems hitherto tested in AAB. In summary, the expression performance of the pBBR1MCS-5-based TetR-Ptet system makes this system highly suitable for applications in G. oxydans and possibly in other AAB. Key Points • A pBBR1MCS-5-based TetR-Ptet system was tunable up to more than 3500-fold induction. • A pBBR1MCS-5-based LacI-PlacUV5 system was leaky and tunable only up to 40-fold. • Modeling of protein-DNA binding suggested decreased DNA binding of LacI at pH < 6. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-021-11473-x.
Collapse
Affiliation(s)
- Philipp Moritz Fricke
- Forschungszentrum Jülich GmbH, IBG-1: Biotechnology, Institute of Bio- and Geosciences, 52425 Jülich, Germany
| | - Martha Lürkens
- RWTH Aachen University, Institute of Biotechnology, Worringerweg 3, 52074 Aachen, Germany
| | - Max Hünnefeld
- Forschungszentrum Jülich GmbH, IBG-1: Biotechnology, Institute of Bio- and Geosciences, 52425 Jülich, Germany
| | - Christiane K. Sonntag
- Forschungszentrum Jülich GmbH, IBG-1: Biotechnology, Institute of Bio- and Geosciences, 52425 Jülich, Germany
| | - Michael Bott
- Forschungszentrum Jülich GmbH, IBG-1: Biotechnology, Institute of Bio- and Geosciences, 52425 Jülich, Germany
| | - Mehdi D. Davari
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
| | - Tino Polen
- Forschungszentrum Jülich GmbH, IBG-1: Biotechnology, Institute of Bio- and Geosciences, 52425 Jülich, Germany
| |
Collapse
|
10
|
Urbančič I, Schiffelers L, Jenkins E, Gong W, Santos AM, Schneider F, O'Brien-Ball C, Vuong MT, Ashman N, Sezgin E, Eggeling C. Aggregation and mobility of membrane proteins interplay with local lipid order in the plasma membrane of T cells. FEBS Lett 2021; 595:2127-2146. [PMID: 34160065 DOI: 10.1002/1873-3468.14153] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/07/2021] [Accepted: 06/18/2021] [Indexed: 01/17/2023]
Abstract
To disentangle the elusive lipid-protein interactions in T-cell activation, we investigate how externally imposed variations in mobility of key membrane proteins (T-cell receptor [TCR], kinase Lck, and phosphatase CD45) affect the local lipid order and protein colocalisation. Using spectral imaging with polarity-sensitive membrane probes in model membranes and live Jurkat T cells, we find that partial immobilisation of proteins (including TCR) by aggregation or ligand binding changes their preference towards a more ordered lipid environment, which can recruit Lck. Our data suggest that the cellular membrane is poised to modulate the frequency of protein encounters upon alterations of their mobility, for example in ligand binding, which offers new mechanistic insight into the involvement of lipid-mediated interactions in membrane-hosted signalling events.
Collapse
Affiliation(s)
- Iztok Urbančič
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Jožef Stefan Institute, Ljubljana, Slovenia
| | - Lisa Schiffelers
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Edward Jenkins
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Weijian Gong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Ana Mafalda Santos
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Falk Schneider
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | | | - Mai Tuyet Vuong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Nicole Ashman
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Erdinc Sezgin
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Christian Eggeling
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
| |
Collapse
|
11
|
Fricke PM, Link T, Gätgens J, Sonntag C, Otto M, Bott M, Polen T. A tunable L-arabinose-inducible expression plasmid for the acetic acid bacterium Gluconobacter oxydans. Appl Microbiol Biotechnol 2020; 104:9267-9282. [PMID: 32974745 PMCID: PMC7567684 DOI: 10.1007/s00253-020-10905-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 01/21/2023]
Abstract
Abstract The acetic acid bacterium (AAB) Gluconobacter oxydans incompletely oxidizes a wide variety of carbohydrates and is therefore used industrially for oxidative biotransformations. For G. oxydans, no system was available that allows regulatable plasmid-based expression. We found that the l-arabinose-inducible PBAD promoter and the transcriptional regulator AraC from Escherichia coli MC4100 performed very well in G. oxydans. The respective pBBR1-based plasmids showed very low basal expression of the reporters β-glucuronidase and mNeonGreen, up to 480-fold induction with 1% l-arabinose, and tunability from 0.1 to 1% l-arabinose. In G. oxydans 621H, l-arabinose was oxidized by the membrane-bound glucose dehydrogenase, which is absent in the multi-deletion strain BP.6. Nevertheless, AraC-PBAD performed similar in both strains in the exponential phase, indicating that a gene knockout is not required for application of AraC-PBAD in wild-type G. oxydans strains. However, the oxidation product arabinonic acid strongly contributed to the acidification of the growth medium in 621H cultures during the stationary phase, which resulted in drastically decreased reporter activities in 621H (pH 3.3) but not in BP.6 cultures (pH 4.4). These activities could be strongly increased quickly solely by incubating stationary cells in d-mannitol-free medium adjusted to pH 6, indicating that the reporters were hardly degraded yet rather became inactive. In a pH-controlled bioreactor, these reporter activities remained high in the stationary phase (pH 6). Finally, we created a multiple cloning vector with araC-PBAD based on pBBR1MCS-5. Together, we demonstrated superior functionality and good tunability of an AraC-PBAD system in G. oxydans that could possibly also be used in other AAB. Key points • We found the AraC-PBADsystem from E. coli MC4100 was well tunable in G. oxydans. • In the absence of AraC orl-arabinose, expression from PBADwas extremely low. • This araC-PBADsystem could also be fully functional in other acetic acid bacteria. Electronic supplementary material The online version of this article (10.1007/s00253-020-10905-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Philipp Moritz Fricke
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Tobias Link
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Jochem Gätgens
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Christiane Sonntag
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Maike Otto
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Michael Bott
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Tino Polen
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.
| |
Collapse
|
12
|
Khosla A, Rodriguez‐Furlan C, Kapoor S, Van Norman JM, Nelson DC. A series of dual-reporter vectors for ratiometric analysis of protein abundance in plants. PLANT DIRECT 2020; 4:e00231. [PMID: 32582876 PMCID: PMC7306620 DOI: 10.1002/pld3.231] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/10/2020] [Accepted: 05/13/2020] [Indexed: 05/06/2023]
Abstract
Ratiometric reporter systems enable comparisons of the abundance of a protein of interest, or "target," relative to a reference protein. Both proteins are encoded on a single transcript but are separated during translation. This arrangement bypasses the potential for discordant expression that can arise when the target and reference proteins are encoded by separate genes. We generated a set of 18 Gateway-compatible vectors termed pRATIO that combine a variety of promoters, fluorescent, and bioluminescent reporters, and 2A "self-cleaving" peptides. These constructs are easily modified to produce additional combinations or introduce new reporter proteins. We found that mScarlet-I provides the best signal-to-noise ratio among several fluorescent reporter proteins during transient expression experiments in Nicotiana benthamiana. Firefly and Gaussia luciferase also produce high signal-to-noise in N. benthamiana. As proof of concept, we used this system to investigate whether degradation of the receptor KAI2 after karrikin treatment is influenced by its subcellular localization. KAI2 is normally found in the cytoplasm and the nucleus of plant cells. In N. benthamiana, karrikin-induced degradation of KAI2 was only observed when it was retained in the nucleus. These vectors are tools to easily monitor in vivo the abundance of a protein that is transiently expressed in plants, and will be particularly useful for investigating protein turnover in response to different stimuli.
Collapse
Affiliation(s)
- Aashima Khosla
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCAUSA
| | | | - Suraj Kapoor
- Department of GeneticsUniversity of GeorgiaAthensGAUSA
| | | | - David C. Nelson
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCAUSA
| |
Collapse
|
13
|
Jin X, Hapsari ND, Lee S, Jo K. DNA binding fluorescent proteins as single-molecule probes. Analyst 2020; 145:4079-4095. [DOI: 10.1039/d0an00218f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNA binding fluorescent proteins are useful probes for a broad range of biological applications.
Collapse
Affiliation(s)
- Xuelin Jin
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
| | - Natalia Diyah Hapsari
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
- Chemistry Education Program
| | - Seonghyun Lee
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
| | - Kyubong Jo
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology
- Sogang University
- Seoul
- Republic of Korea
| |
Collapse
|
14
|
Tutol JN, Kam HC, Dodani SC. Identification of mNeonGreen as a pH-Dependent, Turn-On Fluorescent Protein Sensor for Chloride. Chembiochem 2019; 20:1759-1765. [PMID: 30843313 DOI: 10.1002/cbic.201900147] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Indexed: 11/06/2022]
Abstract
Chloride-sensitive fluorescent proteins generated from laboratory evolution have a characteristic tyrosine residue that interacts with a chloride ion and π-stacks with the chromophore. However, the engineered yellow-green fluorescent protein mNeonGreen lacks this interaction but still binds chloride, as seen in a recently reported crystal structure. Based on its unique coordination sphere, we were curious if chloride could influence the optical properties of mNeonGreen. Here, we present the structure-guided identification and spectroscopic characterization of mNeonGreen as a turn-on fluorescent protein sensor for chloride. Our results show that chloride binding lowers the chromophore pKa and shifts the equilibrium away from the weakly fluorescent phenol form to the highly fluorescent phenolate form, resulting in a pH-dependent, turn-on fluorescence response. Moreover, through mutagenesis, we link this sensing mechanism to a non-coordinating residue in the chloride binding pocket. This discovery sets the stage to further engineer mNeonGreen as a new fluorescent protein-based tool for imaging cellular chloride.
Collapse
Affiliation(s)
- Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| | - Hiu C Kam
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| |
Collapse
|
15
|
Meiresonne NY, Consoli E, Mertens LM, Chertkova AO, Goedhart J, den Blaauwen T. Superfolder mTurquoise2 ox optimized for the bacterial periplasm allows high efficiency in vivo FRET of cell division antibiotic targets. Mol Microbiol 2019; 111:1025-1038. [PMID: 30648295 PMCID: PMC6850650 DOI: 10.1111/mmi.14206] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2019] [Indexed: 11/30/2022]
Abstract
Fluorescent proteins (FPs) are of vital importance to biomedical research. Many of the currently available fluorescent proteins do not fluoresce when expressed in non-native environments, such as the bacterial periplasm. This strongly limits the options for applications that employ multiple FPs, such as multiplex imaging and Förster resonance energy transfer (FRET). To address this issue, we have engineered a new cyan fluorescent protein based on mTurquoise2 (mTq2). The new variant is dubbed superfolder turquoise2ox (sfTq2ox ) and is able to withstand challenging, oxidizing environments. sfTq2ox has improved folding capabilities and can be expressed in the periplasm at higher concentrations without toxicity. This was tied to the replacement of native cysteines that may otherwise form promiscuous disulfide bonds. The improved sfTq2ox has the same spectroscopic properties as mTq2, that is, high fluorescence lifetime and quantum yield. The sfTq2ox -mNeongreen FRET pair allows the detection of periplasmic protein-protein interactions with energy transfer rates exceeding 40%. Employing the new FRET pair, we show the direct interaction of two essential periplasmic cell division proteins FtsL and FtsB and disrupt it by mutations, paving the way for in vivo antibiotic screening. SIGNIFICANCE: The periplasmic space of Gram-negative bacteria contains many regulatory, transport and cell wall-maintaining proteins. A preferred method to investigate these proteins in vivo is by the detection of fluorescent protein fusions. This is challenging since most fluorescent proteins do not fluoresce in the oxidative environment of the periplasm. We assayed popular fluorescent proteins for periplasmic functionality and describe key factors responsible for periplasmic fluorescence. Using this knowledge, we engineered superfolder mTurquoise2ox (sfTq2ox ), a new cyan fluorescent protein, capable of bright fluorescence in the periplasm. We show that our improvements come without a trade-off from its parent mTurquoise2. Employing sfTq2ox as FRET donor, we show the direct in vivo interaction and disruption of unique periplasmic antibiotic targets FtsB and FtsL.
Collapse
Affiliation(s)
- Nils Y. Meiresonne
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Elisa Consoli
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Laureen M.Y. Mertens
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Anna O. Chertkova
- Molecular Cytology and van Leeuwenhoek Centre for Advanced MicroscopySwammerdam Institute for Life Sciences, University of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Joachim Goedhart
- Molecular Cytology and van Leeuwenhoek Centre for Advanced MicroscopySwammerdam Institute for Life Sciences, University of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Tanneke den Blaauwen
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| |
Collapse
|
16
|
Lemke SB, Weidemann T, Cost AL, Grashoff C, Schnorrer F. A small proportion of Talin molecules transmit forces at developing muscle attachments in vivo. PLoS Biol 2019; 17:e3000057. [PMID: 30917109 PMCID: PMC6453563 DOI: 10.1371/journal.pbio.3000057] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 04/08/2019] [Accepted: 03/08/2019] [Indexed: 11/19/2022] Open
Abstract
Cells in developing organisms are subjected to particular mechanical forces that shape tissues and instruct cell fate decisions. How these forces are sensed and transmitted at the molecular level is therefore an important question, one that has mainly been investigated in cultured cells in vitro. Here, we elucidate how mechanical forces are transmitted in an intact organism. We studied Drosophila muscle attachment sites, which experience high mechanical forces during development and require integrin-mediated adhesion for stable attachment to tendons. Therefore, we quantified molecular forces across the essential integrin-binding protein Talin, which links integrin to the actin cytoskeleton. Generating flies expressing 3 Förster resonance energy transfer (FRET)-based Talin tension sensors reporting different force levels between 1 and 11 piconewton (pN) enabled us to quantify physiologically relevant molecular forces. By measuring primary Drosophila muscle cells, we demonstrate that Drosophila Talin experiences mechanical forces in cell culture that are similar to those previously reported for Talin in mammalian cell lines. However, in vivo force measurements at developing flight muscle attachment sites revealed that average forces across Talin are comparatively low and decrease even further while attachments mature and tissue-level tension remains high. Concomitantly, the Talin concentration at attachment sites increases 5-fold as quantified by fluorescence correlation spectroscopy (FCS), suggesting that only a small proportion of Talin molecules are mechanically engaged at any given time. Reducing Talin levels at late stages of muscle development results in muscle–tendon rupture in the adult fly, likely as a result of active muscle contractions. We therefore propose that a large pool of adhesion molecules is required to share high tissue forces. As a result, less than 15% of the molecules experience detectable forces at developing muscle attachment sites at the same time. Our findings define an important new concept of how cells can adapt to changes in tissue mechanics to prevent mechanical failure in vivo. The protein Talin links the transmembrane cell adhesion molecule integrin to the actin cytoskeleton. Quantitative FRET-based force measurements across Talin in vivo reveal that only few Talin molecules are under force during the development of muscle attachment sites. Cells in our body are constantly exposed to mechanical forces, which they need to sense and react to. In previous studies, fluorescent force sensors were developed to demonstrate that individual proteins in adhesion structures of a cell experience forces in the piconewton (pN) range. However, these cells were analyzed in isolation in an artificial plastic or glass environment. Here, we explored forces on adhesion proteins in their natural environment within a developing animal and used the muscle–tendon tissue in the fruit fly Drosophila as a model system. We made genetically modified fly lines with force sensors or controls inserted into the gene that produces the essential adhesion protein Talin. Using these force sensor flies, we found that only a small proportion of all the Talin proteins (<15%) present at developing muscle–tendon attachments experience detectable forces at the same time. Nevertheless, a large amount of Talin is accumulated at these attachments during fly development. We found that this large Talin pool is important to prevent rupture of the muscle–tendon connection in adult flies that produce high muscle forces during flight. In conclusion, we demonstrated that a large pool of Talin proteins is required for stable muscle–tendon attachment, likely with the individual Talin molecules dynamically sharing the mechanical load.
Collapse
Affiliation(s)
- Sandra B. Lemke
- Max Planck Institute of Biochemistry, Martinsried, Germany
- * E-mail: (FS); (CG); (SBL)
| | | | - Anna-Lena Cost
- Max Planck Institute of Biochemistry, Martinsried, Germany
- University of Münster, Institute for Molecular Cell Biology, Münster, Germany
| | - Carsten Grashoff
- Max Planck Institute of Biochemistry, Martinsried, Germany
- University of Münster, Institute for Molecular Cell Biology, Münster, Germany
- * E-mail: (FS); (CG); (SBL)
| | - Frank Schnorrer
- Max Planck Institute of Biochemistry, Martinsried, Germany
- Aix Marseille University, CNRS, IBDM, Marseille, France
- * E-mail: (FS); (CG); (SBL)
| |
Collapse
|