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Rozanova S, Barkovits K, Nikolov M, Schmidt C, Urlaub H, Marcus K. Quantitative Mass Spectrometry-Based Proteomics: An Overview. Methods Mol Biol 2021; 2228:85-116. [PMID: 33950486 DOI: 10.1007/978-1-0716-1024-4_8] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In recent decades, mass spectrometry has moved more than ever before into the front line of protein-centered research. After being established at the qualitative level, the more challenging question of quantification of proteins and peptides using mass spectrometry has become a focus for further development. In this chapter, we discuss and review actual strategies and problems of the methods for the quantitative analysis of peptides, proteins, and finally proteomes by mass spectrometry. The common themes, the differences, and the potential pitfalls of the main approaches are presented in order to provide a survey of the emerging field of quantitative, mass spectrometry-based proteomics.
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Affiliation(s)
- Svitlana Rozanova
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for protein diagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Katalin Barkovits
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for protein diagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Miroslav Nikolov
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.,Hematology/Oncology, Department of Medicine II, Johann Wolfgang Goethe University, Frankfurt, Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany. .,Medical Proteome Analysis, Center for protein diagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany.
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52
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Radixin modulates the function of outer hair cell stereocilia. Commun Biol 2020; 3:792. [PMID: 33361775 PMCID: PMC7758333 DOI: 10.1038/s42003-020-01506-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 11/18/2020] [Indexed: 01/07/2023] Open
Abstract
The stereocilia of the inner ear sensory cells contain the actin-binding protein radixin, encoded by RDX. Radixin is important for hearing but remains functionally obscure. To determine how radixin influences hearing sensitivity, we used a custom rapid imaging technique to visualize stereocilia motion while measuring electrical potential amplitudes during acoustic stimulation. Radixin inhibition decreased sound-evoked electrical potentials. Other functional measures, including electrically induced sensory cell motility and sound-evoked stereocilia deflections, showed a minor amplitude increase. These unique functional alterations demonstrate radixin as necessary for conversion of sound into electrical signals at acoustic rates. We identified patients with RDX variants with normal hearing at birth who showed rapidly deteriorating hearing during the first months of life. This may be overlooked by newborn hearing screening and explained by multiple disturbances in postnatal sensory cells. We conclude radixin is necessary for ensuring normal conversion of sound to electrical signals in the inner ear. Sonal Prasad et al. identify several mutations in the radixin (RDX) gene that are associated with early-life hearing loss. Using a guinea pig model, they propose that radixin helps convert sound into electrical signals in the mature inner ear.
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Sichert A, Corzett CH, Schechter MS, Unfried F, Markert S, Becher D, Fernandez-Guerra A, Liebeke M, Schweder T, Polz MF, Hehemann JH. Verrucomicrobia use hundreds of enzymes to digest the algal polysaccharide fucoidan. Nat Microbiol 2020; 5:1026-1039. [PMID: 32451471 DOI: 10.1038/s41564-020-0720-2] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/06/2020] [Indexed: 12/16/2022]
Abstract
Brown algae are important players in the global carbon cycle by fixing carbon dioxide into 1 Gt of biomass annually, yet the fate of fucoidan-their major cell wall polysaccharide-remains poorly understood. Microbial degradation of fucoidans is slower than that of other polysaccharides, suggesting that fucoidans are more recalcitrant and may sequester carbon in the ocean. This may be due to the complex, branched and highly sulfated structure of fucoidans, which also varies among species of brown algae. Here, we show that 'Lentimonas' sp. CC4, belonging to the Verrucomicrobia, acquired a remarkably complex machinery for the degradation of six different fucoidans. The strain accumulated 284 putative fucoidanases, including glycoside hydrolases, sulfatases and carbohydrate esterases, which are primarily located on a 0.89-megabase pair plasmid. Proteomics reveals that these enzymes assemble into substrate-specific pathways requiring about 100 enzymes per fucoidan from different species of brown algae. These enzymes depolymerize fucoidan into fucose, which is metabolized in a proteome-costly bacterial microcompartment that spatially constrains the metabolism of the toxic intermediate lactaldehyde. Marine metagenomes and microbial genomes show that Verrucomicrobia including 'Lentimonas' are abundant and highly specialized degraders of fucoidans and other complex polysaccharides. Overall, the complexity of the pathways underscores why fucoidans are probably recalcitrant and more slowly degraded, since only highly specialized organisms can effectively degrade them in the ocean.
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Affiliation(s)
- Andreas Sichert
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Center for Marine Environmental Sciences, MARUM, University of Bremen, Bremen, Germany
| | - Christopher H Corzett
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | | | - Frank Unfried
- Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Stephanie Markert
- Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Dörte Becher
- Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Antonio Fernandez-Guerra
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Center for Marine Environmental Sciences, MARUM, University of Bremen, Bremen, Germany
- Lundbeck Foundation GeoGenetics Centre, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Manuel Liebeke
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Thomas Schweder
- Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Martin F Polz
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Jan-Hendrik Hehemann
- Max Planck Institute for Marine Microbiology, Bremen, Germany.
- Center for Marine Environmental Sciences, MARUM, University of Bremen, Bremen, Germany.
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Babenko VV, Ziganshin RH, Weise C, Dyachenko I, Shaykhutdinova E, Murashev AN, Zhmak M, Starkov V, Hoang AN, Tsetlin V, Utkin Y. Novel Bradykinin-Potentiating Peptides and Three-Finger Toxins from Viper Venom: Combined NGS Venom Gland Transcriptomics and Quantitative Venom Proteomics of the Azemiops feae Viper. Biomedicines 2020; 8:biomedicines8080249. [PMID: 32731454 PMCID: PMC7460416 DOI: 10.3390/biomedicines8080249] [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: 06/29/2020] [Revised: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 01/22/2023] Open
Abstract
Feae's viper Azemipos feae belongs to the Azemiopinae subfamily of the Viperidae family. The effects of Viperidae venoms are mostly coagulopathic with limited neurotoxicity manifested by phospholipases A2. From A. feae venom, we have earlier isolated azemiopsin, a novel neurotoxin inhibiting the nicotinic acetylcholine receptor. To characterize other A. feae toxins, we applied label-free quantitative proteomics, which revealed 120 unique proteins, the most abundant being serine proteinases and phospholipases A2. In total, toxins representing 14 families were identified, among which bradykinin-potentiating peptides with unique amino acid sequences possessed biological activity in vivo. The proteomic analysis revealed also basal (commonly known as non-conventional) three-finger toxins belonging to the group of those possessing neurotoxic activity. This is the first indication of the presence of three-finger neurotoxins in viper venom. In parallel, the transcriptomic analysis of venom gland performed by Illumina next-generation sequencing further revealed 206 putative venom transcripts. Together, the study unveiled the venom proteome and venom gland transciptome of A. feae, which in general resemble those of other snakes from the Viperidae family. However, new toxins not found earlier in viper venom and including three-finger toxins and unusual bradykinin-potentiating peptides were discovered.
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Affiliation(s)
- Vladislav V. Babenko
- Federal Research and Clinical Centre of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia;
| | - Rustam H. Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (R.H.Z.); (M.Z.); (V.S.); (V.T.)
| | - Christoph Weise
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany;
| | - Igor Dyachenko
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia; (I.D.); (E.S.); (A.N.M.)
| | - Elvira Shaykhutdinova
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia; (I.D.); (E.S.); (A.N.M.)
| | - Arkady N. Murashev
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia; (I.D.); (E.S.); (A.N.M.)
| | - Maxim Zhmak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (R.H.Z.); (M.Z.); (V.S.); (V.T.)
| | - Vladislav Starkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (R.H.Z.); (M.Z.); (V.S.); (V.T.)
| | - Anh Ngoc Hoang
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City 700000, Vietnam;
| | - Victor Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (R.H.Z.); (M.Z.); (V.S.); (V.T.)
| | - Yuri Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (R.H.Z.); (M.Z.); (V.S.); (V.T.)
- Correspondence: or ; Tel.: +7-495-336-6522
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The human liver matrisome - Proteomic analysis of native and fibrotic human liver extracellular matrices for organ engineering approaches. Biomaterials 2020; 257:120247. [PMID: 32739662 DOI: 10.1016/j.biomaterials.2020.120247] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 07/05/2020] [Accepted: 07/16/2020] [Indexed: 02/06/2023]
Abstract
The production of biomaterials that endow significant morphogenic and microenvironmental cues for the constitution of cell integration and regeneration remains a key challenge in the successful implementation of functional organ replacements. Despite the vast development in the production of biological and architecturally native matrices, the complex compositions and pivotal figures by which the human matrisome mediates many of its essential functions are yet to be defined. Here we present a thorough analysis of the native human liver proteomic landscape using decellularization and defatting protocols to create extracellular matrix scaffolds of natural origin that can further be used in both bottom-up and top-down approaches in tissue engineering based organ replacements. Furthermore, by analyzing human liver extracellular matrices in different stages of fibrosis and cirrhosis, we have identified distinct attributes of these tissues that could potentially be exploited therapeutically and thus require further investigation. The general experimental pipeline presented in this study is applicable to any type of tissue and can be widely used for different approaches in regenerative medicine and in the construction of novel biomaterials for organ engineering approaches.
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56
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Delan-Forino C, Spanos C, Rappsilber J, Tollervey D. Substrate specificity of the TRAMP nuclear surveillance complexes. Nat Commun 2020; 11:3122. [PMID: 32561742 PMCID: PMC7305330 DOI: 10.1038/s41467-020-16965-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 05/29/2020] [Indexed: 01/01/2023] Open
Abstract
During nuclear surveillance in yeast, the RNA exosome functions together with the TRAMP complexes. These include the DEAH-box RNA helicase Mtr4 together with an RNA-binding protein (Air1 or Air2) and a poly(A) polymerase (Trf4 or Trf5). To better determine how RNA substrates are targeted, we analyzed protein and RNA interactions for TRAMP components. Mass spectrometry identified three distinct TRAMP complexes formed in vivo. These complexes preferentially assemble on different classes of transcripts. Unexpectedly, on many substrates, including pre-rRNAs and pre-mRNAs, binding specificity is apparently conferred by Trf4 and Trf5. Clustering of mRNAs by TRAMP association shows co-enrichment for mRNAs with functionally related products, supporting the significance of surveillance in regulating gene expression. We compared binding sites of TRAMP components with multiple nuclear RNA binding proteins, revealing preferential colocalization of subsets of factors. TRF5 deletion reduces Mtr4 recruitment and increases RNA abundance for mRNAs specifically showing high Trf5 binding.
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Affiliation(s)
- Clémentine Delan-Forino
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
| | - Christos Spanos
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
| | - Juri Rappsilber
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355, Berlin, Germany
| | - David Tollervey
- Wellcome Center for Cell Biology, University of Edinburgh, Kings Buildings, Swann Building, Edinburgh, EH9 3BF, UK.
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57
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Song J, Patterson R, Metlagel Z, Krey JF, Hao S, Wang L, Ng B, Sazzed S, Kovacs J, Wriggers W, He J, Barr-Gillespie PG, Auer M. A cryo-tomography-based volumetric model of the actin core of mouse vestibular hair cell stereocilia lacking plastin 1. J Struct Biol 2020; 210:107461. [PMID: 31962158 PMCID: PMC7067663 DOI: 10.1016/j.jsb.2020.107461] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/11/2020] [Accepted: 01/14/2020] [Indexed: 12/11/2022]
Abstract
Electron cryo-tomography allows for high-resolution imaging of stereocilia in their native state. Because their actin filaments have a higher degree of order, we imaged stereocilia from mice lacking the actin crosslinker plastin 1 (PLS1). We found that while stereocilia actin filaments run 13 nm apart in parallel for long distances, there were gaps of significant size that were stochastically distributed throughout the actin core. Actin crosslinkers were distributed through the stereocilium, but did not occupy all possible binding sites. At stereocilia tips, protein density extended beyond actin filaments, especially on the side of the tip where a tip link is expected to anchor. Along the shaft, repeating density was observed that corresponds to actin-to-membrane connectors. In the taper region, most actin filaments terminated near the plasma membrane. The remaining filaments twisted together to make a tighter bundle than was present in the shaft region; the spacing between them decreased from 13 nm to 9 nm, and the apparent filament diameter decreased from 6.4 to 4.8 nm. Our models illustrate detailed features of distinct structural domains that are present within the stereocilium.
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Affiliation(s)
- Junha Song
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Roma Patterson
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Zoltan Metlagel
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jocelyn F Krey
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Samantha Hao
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Linshanshan Wang
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Brian Ng
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Salim Sazzed
- Department of Computer Science, Old Dominion University, Norfolk, VA, USA
| | - Julio Kovacs
- Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA, USA
| | - Willy Wriggers
- Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA, USA
| | - Jing He
- Department of Computer Science, Old Dominion University, Norfolk, VA, USA
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, USA.
| | - Manfred Auer
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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58
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Lai W, Li D, Wang Q, Nan X, Xiang Z, Ma Y, Liu Y, Chen J, Tian J, Fang Q. A Protein Corona Adsorbed to a Bacterial Magnetosome Affects Its Cellular Uptake. Int J Nanomedicine 2020; 15:1481-1498. [PMID: 32189964 PMCID: PMC7065717 DOI: 10.2147/ijn.s220082] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 01/24/2020] [Indexed: 01/01/2023] Open
Abstract
Purpose It is well known that when exposed to human blood plasma, nanoparticles are predominantly coated by a layer of proteins, forming a corona that will mediate the subsequent cell interactions. Magnetosomes are protein-rich membrane nanoparticles which are synthesized by magnetic bacteria; these have gained a lot of attention owing to their unique magnetic and biochemical characteristics. Nevertheless, whether bacterial magnetosomes have a corona after interacting with the plasma, and how such a corona affects nanoparticle–cell interactions is yet to be elucidated. The aim of this study was to characterize corona formation around a bacterial magnetosome and to assess the functional consequences. Methods Magnetosomes were isolated from the magnetotactic bacteria, M. gryphiswaldense (MSR-1). Size, morphology, and zeta potential were measured by transmission electron microscopy and dynamic light scattering. A quantitative characterization of plasma corona proteins was performed using LC-MS/MS. Protein absorption was further examined by circular dichroism and the effect of the corona on cellular uptake was investigated by microscopy and spectroscopy. Results Various serum proteins were found to be selectively adsorbed on the surface of the bacterial magnetosomes following plasma exposure, forming a corona. Compared to the pristine magnetosomes, the acquired corona promoted efficient cellular uptake by human vascular endothelial cells. Using a protein-interaction prediction method, we identified cell surface receptors that could potentially associate with abundant corona components. Of these, one abundant corona protein, ApoE, may be responsible for internalization of the magnetosome-corona complex through LDL receptor-mediated internalization. Conclusion Our findings provide clues as to the physiological response to magnetosomes and also reveal the corona composition of this membrane-coated nanomaterial after exposure to blood plasma.
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Affiliation(s)
- Wenjia Lai
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Dan Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Qingsong Wang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Xiaohui Nan
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Zhichu Xiang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yan Ma
- Aviation Service Department, Yantai Engineering & Technology College, Yantai 264000, People's Republic of China
| | - Ying Liu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Jiankui Chen
- Clinical Laboratory, Affiliated Hospital of Academy of Military Medical Sciences, Beijing 100071, People's Republic of China
| | - Jiesheng Tian
- State Key Laboratories for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, People's Republic of China
| | - Qiaojun Fang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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59
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Kovacs J, Song J, Auer M, He J, Hunter W, Wriggers W. Correction of Missing-Wedge Artifacts in Filamentous Tomograms by Template-Based Constrained Deconvolution. J Chem Inf Model 2020; 60:2626-2633. [PMID: 32045242 DOI: 10.1021/acs.jcim.9b01111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cryo-electron tomography maps often exhibit considerable noise and anisotropic resolution, due to the low-dose requirements and the missing wedge in Fourier space. These spurious features are visually unappealing and, more importantly, prevent an automated segmentation of geometric shapes, requiring a subjective and labor-intensive manual tracing. We developed a novel computational strategy for objectively denoising and correcting missing-wedge artifacts in homogeneous specimen areas of tomograms, where it is assumed that a template repeats itself across the volume under consideration, as happens in the case of filaments. In our deconvolution approach, we use a template and a map of corresponding template locations, allowing us to compensate for the information lost in the missing wedge. We applied the method to tomograms of actin-filament bundles of inner-ear stereocilia, which are critical for the senses of hearing and balance. In addition, we demonstrate that our method can be used for cell membrane detection.
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Affiliation(s)
- Julio Kovacs
- Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Junha Song
- Cell and Tissue Imaging, Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| | - Manfred Auer
- Cell and Tissue Imaging, Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| | - Jing He
- Department of Computer Science, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Wade Hunter
- Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Willy Wriggers
- Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529, United States
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60
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Exploration of the propagation of transpovirons within Mimiviridae reveals a unique example of commensalism in the viral world. ISME JOURNAL 2019; 14:727-739. [PMID: 31822788 PMCID: PMC7031253 DOI: 10.1038/s41396-019-0565-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 01/27/2023]
Abstract
Acanthamoeba-infecting Mimiviridae are giant viruses with dsDNA genome up to 1.5 Mb. They build viral factories in the host cytoplasm in which the nuclear-like virus-encoded functions take place. They are themselves the target of infections by 20-kb-dsDNA virophages, replicating in the giant virus factories and can also be found associated with 7-kb-DNA episomes, dubbed transpovirons. Here we isolated a virophage (Zamilon vitis) and two transpovirons respectively associated to B- and C-clade mimiviruses. We found that the virophage could transfer each transpoviron provided the host viruses were devoid of a resident transpoviron (permissive effect). If not, only the resident transpoviron originally isolated from the corresponding virus was replicated and propagated within the virophage progeny (dominance effect). Although B- and C-clade viruses devoid of transpoviron could replicate each transpoviron, they did it with a lower efficiency across clades, suggesting an ongoing process of adaptive co-evolution. We analysed the proteomes of host viruses and virophage particles in search of proteins involved in this adaptation process. This study also highlights a unique example of intricate commensalism in the viral world, where the transpoviron uses the virophage to propagate and where the Zamilon virophage and the transpoviron depend on the giant virus to replicate, without affecting its infectious cycle.
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Solga R, Behrens J, Ziemann A, Riou A, Berwanger C, Becker L, Garrett L, de Angelis MH, Fischer L, Coras R, Barkovits K, Marcus K, Mahabir E, Eichinger L, Schröder R, Noegel AA, Clemen CS. CRN2 binds to TIMP4 and MMP14 and promotes perivascular invasion of glioblastoma cells. Eur J Cell Biol 2019; 98:151046. [PMID: 31677819 DOI: 10.1016/j.ejcb.2019.151046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/13/2019] [Accepted: 09/30/2019] [Indexed: 12/21/2022] Open
Abstract
CRN2 is an actin filament binding protein involved in the regulation of various cellular processes including cell migration and invasion. CRN2 has been implicated in the malignant progression of different types of human cancer. We used CRN2 knock-out mice for analyses as well as for crossbreeding with a Tp53/Pten knock-out glioblastoma mouse model. CRN2 knock-out mice were subjected to a phenotyping screen at the German Mouse Clinic. Murine glioblastoma tissue specimens as well as cultured murine brain slices and glioblastoma cell lines were investigated by immunohistochemistry, immunofluorescence, and cell biological experiments. Protein interactions were studied by immunoprecipitation, pull-down, and enzyme activity assays. CRN2 knock-out mice displayed neurological and behavioural alterations, e.g. reduced hearing sensitivity, reduced acoustic startle response, hypoactivity, and less frequent urination. While glioblastoma mice with or without the additional CRN2 knock-out allele exhibited no significant difference in their survival rates, the increased levels of CRN2 in transplanted glioblastoma cells caused a higher tumour cell encasement of murine brain slice capillaries. We identified two important factors of the tumour microenvironment, the tissue inhibitor of matrix metalloproteinase 4 (TIMP4) and the matrix metalloproteinase 14 (MMP14, synonym: MT1-MMP), as novel binding partners of CRN2. All three proteins mutually interacted and co-localised at the front of lamellipodia, and CRN2 was newly detected in exosomes. On the functional level, we demonstrate that CRN2 increased the secretion of TIMP4 as well as the catalytic activity of MMP14. Our results imply that CRN2 represents a pro-invasive effector within the tumour cell microenvironment of glioblastoma multiforme.
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Affiliation(s)
- Roxana Solga
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Juliane Behrens
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Anja Ziemann
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Adrien Riou
- In-vivo NMR, Max Planck Institute for Metabolism Research, 50931, Cologne, Germany
| | - Carolin Berwanger
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany; Institute of Aerospace Medicine, German Aerospace Center (DLR), 51147, Cologne, Germany
| | - Lore Becker
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Centre Munich, German Research Centre for Environmental Health, 85764, Neuherberg, Germany
| | - Lillian Garrett
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Centre Munich, German Research Centre for Environmental Health, 85764, Neuherberg, Germany; Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Centre Munich, German Research Centre for Environmental Health, 85764, Neuherberg, Germany; Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, 85354, Freising, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Lisa Fischer
- Comparative Medicine, Center for Molecular Medicine Cologne, University of Cologne, 50931, Cologne, Germany
| | - Roland Coras
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Katalin Barkovits
- Medizinisches Proteom‑Center, Medical Faculty, Ruhr-University Bochum, 44801, Bochum, Germany
| | - Katrin Marcus
- Medizinisches Proteom‑Center, Medical Faculty, Ruhr-University Bochum, 44801, Bochum, Germany
| | - Esther Mahabir
- Comparative Medicine, Center for Molecular Medicine Cologne, University of Cologne, 50931, Cologne, Germany
| | - Ludwig Eichinger
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Rolf Schröder
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Angelika A Noegel
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany.
| | - Christoph S Clemen
- Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany; Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany; Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931, Cologne, Germany.
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62
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Wang X, He B, Shi J, Li Q, Zhu HJ. Comparative Proteomics Analysis of Human Liver Microsomes and S9 Fractions. Drug Metab Dispos 2019; 48:31-40. [PMID: 31699809 DOI: 10.1124/dmd.119.089235] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/30/2019] [Indexed: 01/09/2023] Open
Abstract
Human liver microsomes (HLM) and human liver S9 fractions (HLS9) are commonly used to study drug metabolism in vitro. However, a quantitative comparison of HLM and HLS9 proteomes is lacking, resulting in the arbitrary selection of one hepatic preparation over another and in difficulties with data interpretation. In this study, we applied a label-free global absolute quantitative proteomics method to the analysis of HLS9 and the corresponding HLM prepared from 102 individual human livers. A total of 3137 proteins were absolutely quantified, and 3087 of those were determined in both HLM and HLS9. Protein concentrations were highly correlated between the two hepatic preparations (R = 0.87, P < 0.0001). We reported the concentrations of 98 drug-metabolizing enzymes (DMEs) and 51 transporters, and demonstrated significant differences between their abundances in HLM and HLS9. We also revealed the protein-protein correlations among these DMEs and transporters and the sex effect on the HLM and HLS9 proteomes. Additionally, HLM and HLS9 displayed distinct expression patterns for protein markers of cytosol and various cellular organelles. Moreover, we evaluated the interindividual variability of three housekeeping proteins, and identified five proteins with low variation across individuals that have the potential to serve as new internal controls for western blot experiments. In summary, these results will lead to better understanding of data obtained from HLM and HLS9 and assist in in vitro-in vivo extrapolations. Knowing the differences between HLM and HLS9 also allows us to make better-informed decisions when choosing between these two hepatic preparations for in vitro drug metabolism studies. SIGNIFICANCE STATEMENT: This investigation revealed significant differences in protein concentrations of drug-metabolizing enzymes and transporters between human liver microsomes and S9 fractions. We also determined the protein-protein correlations among the drug-metabolizing enzymes and transporters and the sex effect on the proteomes of these two hepatic preparations. The results will help interpret data obtained from these two preparations and allow us to make more informed decisions when choosing between human liver microsomes and S9 fractions for in vitro drug metabolism studies.
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Affiliation(s)
- Xinwen Wang
- Department of Clinical Pharmacy, University of Michigan, Ann Arbor, Michigan (X.W., B.H., J.S., H.-J.Z.); and School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China (Q.L.)
| | - Bing He
- Department of Clinical Pharmacy, University of Michigan, Ann Arbor, Michigan (X.W., B.H., J.S., H.-J.Z.); and School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China (Q.L.)
| | - Jian Shi
- Department of Clinical Pharmacy, University of Michigan, Ann Arbor, Michigan (X.W., B.H., J.S., H.-J.Z.); and School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China (Q.L.)
| | - Qian Li
- Department of Clinical Pharmacy, University of Michigan, Ann Arbor, Michigan (X.W., B.H., J.S., H.-J.Z.); and School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China (Q.L.)
| | - Hao-Jie Zhu
- Department of Clinical Pharmacy, University of Michigan, Ann Arbor, Michigan (X.W., B.H., J.S., H.-J.Z.); and School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China (Q.L.)
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63
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Zhu Y, Scheibinger M, Ellwanger DC, Krey JF, Choi D, Kelly RT, Heller S, Barr-Gillespie PG. Single-cell proteomics reveals changes in expression during hair-cell development. eLife 2019; 8:50777. [PMID: 31682227 PMCID: PMC6855842 DOI: 10.7554/elife.50777] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/01/2019] [Indexed: 12/12/2022] Open
Abstract
Hearing and balance rely on small sensory hair cells that reside in the inner ear. To explore dynamic changes in the abundant proteins present in differentiating hair cells, we used nanoliter-scale shotgun mass spectrometry of single cells, each ~1 picoliter, from utricles of embryonic day 15 chickens. We identified unique constellations of proteins or protein groups from presumptive hair cells and from progenitor cells. The single-cell proteomes enabled the de novo reconstruction of a developmental trajectory using protein expression levels, revealing proteins that greatly increased in expression during differentiation of hair cells (e.g., OCM, CRABP1, GPX2, AK1, GSTO1) and those that decreased during differentiation (e.g., TMSB4X, AGR3). Complementary single-cell transcriptome profiling showed corresponding changes in mRNA during maturation of hair cells. Single-cell proteomics data thus can be mined to reveal features of cellular development that may be missed with transcriptomics.
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Affiliation(s)
- Ying Zhu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, United States
| | - Mirko Scheibinger
- Department of Otolaryngology Head and Neck Surgery, Stanford University, Stanford, United States
| | - Daniel Christian Ellwanger
- Department of Otolaryngology Head and Neck Surgery, Stanford University, Stanford, United States.,Genome Analysis Unit, Amgen Research, Amgen Inc, South San Francisco, United States
| | - Jocelyn F Krey
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, United States.,Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Dongseok Choi
- OHSU-PSU School of Public Health, Oregon Health & Science University, Portland, United States.,Graduate School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Ryan T Kelly
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, United States.,Department of Chemistry and Biochemistry, Brigham Young University, Provo, United States
| | - Stefan Heller
- Department of Otolaryngology Head and Neck Surgery, Stanford University, Stanford, United States
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, United States.,Vollum Institute, Oregon Health & Science University, Portland, United States
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64
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Israel S, Casser E, Drexler HCA, Fuellen G, Boiani M. A framework for TRIM21-mediated protein depletion in early mouse embryos: recapitulation of Tead4 null phenotype over three days. BMC Genomics 2019; 20:755. [PMID: 31638890 PMCID: PMC6805607 DOI: 10.1186/s12864-019-6106-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/13/2019] [Indexed: 12/17/2022] Open
Abstract
Background While DNA and RNA methods are routine to disrupt the expression of specific genes, complete understanding of developmental processes requires also protein methods, because: oocytes and early embryos accumulate proteins and these are not directly affected by DNA and RNA methods. When proteins in the oocyte encounter a specific antibody and the TRIpartite Motiv-containing 21 (TRIM21) ubiquitin-protein ligase, they can be committed to degradation in the proteasome, producing a transient functional knock-out that reveals the role of the protein. However, there are doubts about whether this targeted proteolysis could be successfully used to study mammalian development, because duration of the transient effect is unknown, and also because amounts of reagents delivered must be adequate in relation to the amount of target protein, which is unknown, too. Results We show that the mouse egg contains up to 1E-02 picomoles/protein, as estimated by mass spectrometry using the intensity-based absolute quantification (iBAQ) algorithm. However, the egg can only accommodate ≈1E-04 picomoles of antibody or TRIM21 without incurring toxic effects. Within this framework, we demonstrate that TRIM21-mediated protein depletion efficiently disrupts the embryonic process of trophectoderm formation, which critically depends on the TEA domain family member 4 (Tead4) gene. TEAD4 depletion starting at the 1-cell stage lasts for 3 days prior to a return of gene and protein expression to baseline. This time period is long enough to result in a phenotype entirely consistent with that of the published null mutation and RNA interference studies: significant underexpression of trophectodermal genes Cdx2 and Gata3 and strongly impaired ability of embryos to cavitate and implant in the uterus. Omics data are available via ProteomeXchange (PXD012613) and GEO (GSE124844). Conclusions TRIM21-mediated protein depletion can be an effective means to disrupt gene function in mouse development, provided the target gene is chosen carefully and the method is tuned accurately. The knowledge gathered in this study provides the basic know-how (prerequisites, requirements, limitations) to expedite the protein depletion of other genes besides Tead4.
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Affiliation(s)
- Steffen Israel
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany
| | - Ellen Casser
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany
| | - Hannes C A Drexler
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany
| | - Georg Fuellen
- Rostock University Medical Center, Institute for Biostatistics and Informatics in Medicine and Aging Research (IBIMA), Ernst-Heydemann-Strasse 8, 18057, Rostock, Germany
| | - Michele Boiani
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany.
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65
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Fecher C, Trovò L, Müller SA, Snaidero N, Wettmarshausen J, Heink S, Ortiz O, Wagner I, Kühn R, Hartmann J, Karl RM, Konnerth A, Korn T, Wurst W, Merkler D, Lichtenthaler SF, Perocchi F, Misgeld T. Cell-type-specific profiling of brain mitochondria reveals functional and molecular diversity. Nat Neurosci 2019; 22:1731-1742. [DOI: 10.1038/s41593-019-0479-z] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 07/25/2019] [Indexed: 12/21/2022]
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66
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Ryabinin VV, Ziganshin RH, Starkov VG, Tsetlin VI, Utkin YN. Intraspecific Variability in the Composition of the Venom from Monocled Cobra (Naja kaouthia). RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1068162019020109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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67
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Jen HI, Hill MC, Tao L, Sheng K, Cao W, Zhang H, Yu HV, Llamas J, Zong C, Martin JF, Segil N, Groves AK. Transcriptomic and epigenetic regulation of hair cell regeneration in the mouse utricle and its potentiation by Atoh1. eLife 2019; 8:e44328. [PMID: 31033441 PMCID: PMC6504235 DOI: 10.7554/elife.44328] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/28/2019] [Indexed: 12/30/2022] Open
Abstract
The mammalian cochlea loses its ability to regenerate new hair cells prior to the onset of hearing. In contrast, the adult vestibular system can produce new hair cells in response to damage, or by reprogramming of supporting cells with the hair cell transcription factor Atoh1. We used RNA-seq and ATAC-seq to probe the transcriptional and epigenetic responses of utricle supporting cells to damage and Atoh1 transduction. We show that the regenerative response of the utricle correlates with a more accessible chromatin structure in utricle supporting cells compared to their cochlear counterparts. We also provide evidence that Atoh1 transduction of supporting cells is able to promote increased transcriptional accessibility of some hair cell genes. Our study offers a possible explanation for regenerative differences between sensory organs of the inner ear, but shows that additional factors to Atoh1 may be required for optimal reprogramming of hair cell fate.
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Affiliation(s)
- Hsin-I Jen
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Matthew C Hill
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Litao Tao
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Kuanwei Sheng
- Program in Integrative Molecular and Biomedical SciencesBaylor College of MedicineHoustonUnited States
| | - Wenjian Cao
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Hongyuan Zhang
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
| | - Haoze V Yu
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Juan Llamas
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Chenghang Zong
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - James F Martin
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular Physiology and BiophysicsBaylor College of MedicineHoustonUnited States
- The Texas Heart InstituteHoustonUnited States
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Andrew K Groves
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
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68
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Nam JH, Grant JW, Rowe MH, Peterson EH. Multiscale modeling of mechanotransduction in the utricle. J Neurophysiol 2019; 122:132-150. [PMID: 30995138 DOI: 10.1152/jn.00068.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We review recent progress in using numerical models to relate utricular hair bundle and otoconial membrane (OM) structure to the functional requirements imposed by natural behavior in turtles. The head movements section reviews the evolution of experimental attempts to understand vestibular system function with emphasis on turtles, including data showing that accelerations occurring during natural head movements achieve higher magnitudes and frequencies than previously assumed. The structure section reviews quantitative anatomical data documenting topographical variation in the structures underlying macromechanical and micromechanical responses of the turtle utricle to head movement: hair bundles, OM, and bundle-OM coupling. The macromechanics section reviews macromechanical models that incorporate realistic anatomical and mechanical parameters and reveal that the system is significantly underdamped, contrary to previous assumptions. The micromechanics: hair bundle motion and met currents section reviews work based on micromechanical models, which demonstrates that topographical variation in the structure of hair bundles and OM, and their mode of coupling, result in regional specializations for signaling of low frequency (or static) head position and high frequency head accelerations. We conclude that computational models based on empirical data are especially promising for investigating mechanotransduction in this challenging sensorimotor system.
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Affiliation(s)
- Jong-Hoon Nam
- Department of Mechanical Engineering, Department of Biomedical Engineering, University of Rochester , Rochester, New York
| | - J W Grant
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia
| | - M H Rowe
- Department of Biology, Neuroscience Program, Quantitative Biology Institute, Ohio University , Athens, Ohio
| | - E H Peterson
- Department of Biology, Neuroscience Program, Quantitative Biology Institute, Ohio University , Athens, Ohio
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69
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Wagner EL, Shin JB. Mechanisms of Hair Cell Damage and Repair. Trends Neurosci 2019; 42:414-424. [PMID: 30992136 DOI: 10.1016/j.tins.2019.03.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/04/2019] [Accepted: 03/13/2019] [Indexed: 01/22/2023]
Abstract
Sensory hair cells of the inner ear are exposed to continuous mechanical stress, causing damage over time. The maintenance of hair cells is further challenged by damage from a variety of other ototoxic factors, including loud noise, aging, genetic defects, and ototoxic drugs. This damage can manifest in many forms, from dysfunction of the hair cell mechanotransduction complex to loss of specialized ribbon synapses, and may even result in hair cell death. Given that mammalian hair cells do not regenerate, the repair of hair cell damage is important for continued auditory function throughout life. Here, we discuss how several key hair cell structures can be damaged, and what is known about how they are repaired.
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Affiliation(s)
- Elizabeth L Wagner
- Department of Neuroscience, University of Virginia-School of Medicine, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, University of Virginia-School of Medicine, Charlottesville, VA 22908, USA
| | - Jung-Bum Shin
- Department of Neuroscience, University of Virginia-School of Medicine, Charlottesville, VA 22908, USA.
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70
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Abstract
This chapter describes a basic workflow for analyzing the protein composition of influenza virions. In order to obtain suitable material, the chapter describes how to concentrate influenza virions from the growth media of infected cells and to purify them by ultracentrifugation through a density gradient. This approach is also suitable for purifying influenza virions from the allantoic fluid of embryonated chicken eggs. As a small quantity of microvesicles are co-purified with virions, optional steps are included to increase the stringency of purification by enriching material with viral receptor binding and cleaving activity. Material purified in this way can be used for a variety of downstream applications, including proteomics. As a detailed example of this, the chapter also describes a standard workflow for analyzing the protein composition of concentrated virions by liquid chromatography and tandem mass spectrometry.
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Affiliation(s)
| | - Monika Stegmann
- University of Oxford Advanced Proteomics Facility, Oxford, UK
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71
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Label-free absolute protein quantification with data-independent acquisition. J Proteomics 2019; 200:51-59. [PMID: 30880166 DOI: 10.1016/j.jprot.2019.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/19/2019] [Accepted: 03/06/2019] [Indexed: 02/05/2023]
Abstract
Despite data-independent acquisition (DIA) has been increasingly used for relative protein quantification, DIA-based label-free absolute quantification method has not been fully established. Here we present a novel DIA method using the TPA algorithm (DIA-TPA) for the absolute quantification of protein expressions in human liver microsomal and S9 samples. To validate this method, both data-dependent acquisition (DDA) and DIA experiments were conducted on 36 individual human liver microsome and S9 samples. The MS2-based DIA-TPA was able to quantify approximately twice as many proteins as the MS1-based DDA-TPA method, whereas protein concentrations determined by the two approaches were comparable. To evaluate the accuracy of the DIA-TPA method, we absolutely quantified carboxylesterase 1 concentrations in human liver S9 fractions using an established SILAC internal standard-based proteomic assay; the SILAC results were consistent with those obtained from DIA-TPA analysis. Finally, we employed a unique algorithm in DIA-TPA to distribute the MS signals from shared peptides to individual proteins or isoforms and successfully applied the method to the absolute quantification of several drug-metabolizing enzymes in human liver microsomes. In sum, the DIA-TPA method not only can absolutely quantify entire proteomes and specific proteins, but also has the capability quantifying proteins with shared peptides. SIGNIFICANCE: Data independent acquisition (DIA) has emerged as a powerful approach for relative protein quantification at the whole proteome level. However, DIA-based label-free absolute protein quantification (APQ) method has not been fully established. In the present study, we present a novel DIA-based label-free APQ approach, named DIA-TPA, with the capability absolutely quantifying proteins with shared peptides. The method was validated by comparing the quantification results of DIA-TPA with that obtained from stable isotope-labeled internal standard-based proteomic assays.
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72
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Du TT, Dewey JB, Wagner EL, Cui R, Heo J, Park JJ, Francis SP, Perez-Reyes E, Guillot SJ, Sherman NE, Xu W, Oghalai JS, Kachar B, Shin JB. LMO7 deficiency reveals the significance of the cuticular plate for hearing function. Nat Commun 2019; 10:1117. [PMID: 30850599 PMCID: PMC6408450 DOI: 10.1038/s41467-019-09074-4] [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] [Received: 06/27/2018] [Accepted: 02/15/2019] [Indexed: 12/25/2022] Open
Abstract
Sensory hair cells, the mechanoreceptors of the auditory and vestibular systems, harbor two specialized elaborations of the apical surface, the hair bundle and the cuticular plate. In contrast to the extensively studied mechanosensory hair bundle, the cuticular plate is not as well understood. It is believed to provide a rigid foundation for stereocilia motion, but specifics about its function, especially the significance of its integrity for long-term maintenance of hair cell mechanotransduction, are not known. We discovered that a hair cell protein called LIM only protein 7 (LMO7) is specifically localized in the cuticular plate and the cell junction. Lmo7 KO mice suffer multiple cuticular plate deficiencies, including reduced filamentous actin density and abnormal stereociliar rootlets. In addition to the cuticular plate defects, older Lmo7 KO mice develop abnormalities in inner hair cell stereocilia. Together, these defects affect cochlear tuning and sensitivity and give rise to late-onset progressive hearing loss.
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MESH Headings
- Actins/metabolism
- Animals
- Cochlea/physiology
- Disease Models, Animal
- Hair Cells, Auditory/physiology
- Hair Cells, Auditory/ultrastructure
- Hair Cells, Auditory, Inner/physiology
- Hair Cells, Auditory, Inner/ultrastructure
- Hearing/genetics
- Hearing/physiology
- Hearing Loss/etiology
- Hearing Loss/genetics
- Hearing Loss/physiopathology
- LIM Domain Proteins/deficiency
- LIM Domain Proteins/genetics
- LIM Domain Proteins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Knockout
- Microscopy, Electron, Scanning
- Stereocilia/genetics
- Stereocilia/physiology
- Stereocilia/ultrastructure
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/physiology
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Affiliation(s)
- Ting-Ting Du
- Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - James B Dewey
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, 90033, USA
| | - Elizabeth L Wagner
- Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Runjia Cui
- National Institute for Deafness and Communications Disorders, National Institute of Health, Bethesda, MD, 20892, USA
| | - Jinho Heo
- Center for Cell Signaling and Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jeong-Jin Park
- Biomolecular Analysis Facility, University of Virginia, Charlottesville, VA, 22908, USA
| | - Shimon P Francis
- Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Stacey J Guillot
- Advanced Microscopy core, University of Virginia, Charlottesville, VA, 22908, USA
| | - Nicholas E Sherman
- Biomolecular Analysis Facility, University of Virginia, Charlottesville, VA, 22908, USA
| | - Wenhao Xu
- Genetically Engineered Murine Model (GEMM) core, University of Virginia, Charlottesville, VA, 22908, USA
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, 90033, USA
| | - Bechara Kachar
- National Institute for Deafness and Communications Disorders, National Institute of Health, Bethesda, MD, 20892, USA
| | - Jung-Bum Shin
- Department of Neuroscience, University of Virginia, Charlottesville, VA, 22908, USA.
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Metlagel Z, Krey JF, Song J, Swift MF, Tivol WJ, Dumont RA, Thai J, Chang A, Seifikar H, Volkmann N, Hanein D, Barr-Gillespie PG, Auer M. Electron cryo-tomography of vestibular hair-cell stereocilia. J Struct Biol 2019; 206:149-155. [PMID: 30822456 DOI: 10.1016/j.jsb.2019.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 02/13/2019] [Accepted: 02/17/2019] [Indexed: 11/24/2022]
Abstract
High-resolution imaging of hair-cell stereocilia of the inner ear has contributed substantially to our understanding of auditory and vestibular function. To provide three-dimensional views of the structure of stereocilia cytoskeleton and membranes, we developed a method for rapidly freezing unfixed stereocilia on electron microscopy grids, which allowed subsequent 3D imaging by electron cryo-tomography. Structures of stereocilia tips, shafts, and tapers were revealed, demonstrating that the actin paracrystal was not perfectly ordered. This sample-preparation and imaging procedure will allow for examination of structural features of stereocilia in a near-native state.
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Affiliation(s)
- Zoltan Metlagel
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jocelyn F Krey
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Junha Song
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mark F Swift
- Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, San Diego, USA
| | - William J Tivol
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Rachel A Dumont
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Jasmine Thai
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Alex Chang
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Helia Seifikar
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Niels Volkmann
- Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, San Diego, USA
| | - Dorit Hanein
- Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, San Diego, USA
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Manfred Auer
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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74
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Hereditary hearing loss; about the known and the unknown. Hear Res 2019; 376:58-68. [PMID: 30665849 DOI: 10.1016/j.heares.2019.01.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/11/2018] [Accepted: 01/07/2019] [Indexed: 01/01/2023]
Abstract
Hereditary hearing loss is both clinically and genetically very heterogeneous. Despite the large number of genes that have been associated with the condition, many cases remain unexplained. Novel gene associations with hearing loss are to be expected but also are defects of regulatory regions of the genome which are currently not routinely addressed in molecular genetic testing and research. Inheritance patterns other than monogenic might be more common than assumed in isolated cases and diagnoses might have been missed because of misinterpretation of identified DNA variants. This review summarizes current insights in the genetics of hearing loss, the next steps that are being taken in research, and their challenges. Furthermore, genotype-phenotype correlations and modifying factors are discussed as these are instrumental in counselling hearing impaired individuals and/or their family members.
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75
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Krey JF, Barr-Gillespie PG. Molecular Composition of Vestibular Hair Bundles. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033209. [PMID: 29844221 DOI: 10.1101/cshperspect.a033209] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The vertebrate hair bundle, responsible for transduction of mechanical signals into receptor potentials in sensory hair cells, is an evolutionary masterpiece. Composed of actin-filled stereocilia of precisely regulated length, width, and number, the structure of the hair bundle is optimized for sensing auditory and vestibular stimuli. Recent developments in identifying the lipids and proteins constituting the hair bundle, obtained through genetics, biochemistry, and imaging, now permit a description of the consensus composition of vestibular bundles of mouse, rat, and chick.
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Affiliation(s)
- Jocelyn F Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
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76
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Vélez-Ortega AC, Frolenkov GI. Building and repairing the stereocilia cytoskeleton in mammalian auditory hair cells. Hear Res 2019; 376:47-57. [PMID: 30638948 DOI: 10.1016/j.heares.2018.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/19/2018] [Accepted: 12/28/2018] [Indexed: 10/27/2022]
Abstract
Despite all recent achievements in identification of the molecules that are essential for the structure and mechanosensory function of stereocilia bundles in the auditory hair cells of mammalian species, we still have only a rudimentary understanding of the mechanisms of stereocilia formation, maintenance, and repair. Important molecular differences distinguishing mammalian auditory hair cells from hair cells of other types and species have been recently revealed. In addition, we are beginning to solve the puzzle of the apparent life-long stability of the stereocilia bundles in these cells. New data link the stability of the cytoskeleton in the mammalian auditory stereocilia with the normal activity of mechanotransduction channels. These data suggest new ideas on how a terminally-differentiated non-regenerating hair cell in the mammalian cochlea may repair and tune its stereocilia bundle throughout the life span of the organism.
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Affiliation(s)
- A Catalina Vélez-Ortega
- Department of Physiology, University of Kentucky, 800 Rose St., Lexington, KY, 40536-0298, USA.
| | - Gregory I Frolenkov
- Department of Physiology, University of Kentucky, 800 Rose St., Lexington, KY, 40536-0298, USA.
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77
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Diaz-Horta O, Abad C, Cengiz FB, Bademci G, Blackwelder P, Walz K, Tekin M. Ripor2 is involved in auditory hair cell stereociliary bundle structure and orientation. J Mol Med (Berl) 2018; 96:1227-1238. [PMID: 30280293 PMCID: PMC6238639 DOI: 10.1007/s00109-018-1694-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/20/2018] [Accepted: 09/07/2018] [Indexed: 11/30/2022]
Abstract
RIPOR2 (previously known as FAM65B) localizes to stereocilia of auditory hair cells and causes deafness when its function is disturbed by mutations. Here, we demonstrate that during the morphogenesis of the hair cell bundle, absence of Ripor2 affects the orientation of this key subcellular structure. We show that Ripor2 interacts with Myh9, a protein encoded by a known deafness gene. Absence of Ripor2 is associated with low Myh9 abundance in the mouse cochlea despite increased amount of Myh9 transcripts. While Myh9 is mainly expressed in stereocilia, a phosphorylated form of Myh9 is particularly enriched in the kinocilium. In Ripor2-deficient mice, kinocilium shows an aberrant localization which associates with a reduced content of phosphorylated Myh9. Acetylated alpha tubulin, another specific kinociliary protein which contributes to microtubule stabilization, is reduced in the absence of Ripor2 as well. We propose that Ripor2 deficiency influences abundance and/or post-translational modifications of proteins expressed in both stereocilia and kinocilia. This effect may have a negative impact on the structure and function of the auditory hair cell bundle.
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Affiliation(s)
- Oscar Diaz-Horta
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Clemer Abad
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Filiz Basak Cengiz
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Guney Bademci
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Pat Blackwelder
- MGS/RSMAS and UMCAM/Chemistry, University of Miami, Coral Gables, FL, 33146, USA
- NSU Oceanographic Center, Dania Beach, FL, 33004, USA
| | - Katherina Walz
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Mustafa Tekin
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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78
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Kretzschmar FK, Mengel LA, Müller AO, Schmitt K, Blersch KF, Valerius O, Braus GH, Ischebeck T. PUX10 Is a Lipid Droplet-Localized Scaffold Protein That Interacts with CELL DIVISION CYCLE48 and Is Involved in the Degradation of Lipid Droplet Proteins. THE PLANT CELL 2018; 30:2137-2160. [PMID: 30087207 PMCID: PMC6181012 DOI: 10.1105/tpc.18.00276] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/12/2018] [Accepted: 07/31/2018] [Indexed: 05/07/2023]
Abstract
The number of known proteins associated with plant lipid droplets (LDs) is small compared with other organelles. Many aspects of LD biosynthesis and degradation are unknown, and identifying and characterizing candidate LD proteins could help elucidate these processes. Here, we analyzed the proteome of LD-enriched fractions isolated from tobacco (Nicotiana tabacum) pollen tubes. Proteins that were highly enriched in comparison with the total or cytosolic fraction were further tested for LD localization via transient expression in pollen tubes. One of these proteins, PLANT UBX DOMAIN-CONTAINING PROTEIN10 (PUX10), is a member of the plant UBX domain-containing (PUX) protein family. This protein localizes to LDs via a unique hydrophobic polypeptide sequence and can recruit the AAA-type ATPase CELL DIVISION CYCLE48 (CDC48) protein via its UBX domain. PUX10 is conserved in Arabidopsis thaliana and expressed in embryos, pollen tubes, and seedlings. In pux10 knockout mutants in Arabidopsis, LD size is significantly increased. Proteomic analysis of pux10 mutants revealed a delayed degradation of known LD proteins, some of which possessed ubiquitination sites. We propose that PUX10 is involved in a protein degradation pathway at LDs, mediating an interaction between polyubiquitinated proteins targeted for degradation and downstream effectors such as CDC48.
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Affiliation(s)
- Franziska K Kretzschmar
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37077 Göttingen, Germany
| | - Laura A Mengel
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37077 Göttingen, Germany
| | - Anna O Müller
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37077 Göttingen, Germany
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics, Georg-August-University, Institute for Microbiology and Genetics, 37077 Göttingen, Germany
| | - Katharina F Blersch
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37077 Göttingen, Germany
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics, Georg-August-University, Institute for Microbiology and Genetics, 37077 Göttingen, Germany
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics, Georg-August-University, Institute for Microbiology and Genetics, 37077 Göttingen, Germany
| | - Till Ischebeck
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37077 Göttingen, Germany
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79
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Adaptive mechanisms that provide competitive advantages to marine bacteroidetes during microalgal blooms. ISME JOURNAL 2018; 12:2894-2906. [PMID: 30061707 PMCID: PMC6246565 DOI: 10.1038/s41396-018-0243-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 06/22/2018] [Accepted: 06/30/2018] [Indexed: 01/15/2023]
Abstract
Polysaccharide degradation by heterotrophic microbes is a key process within Earth's carbon cycle. Here, we use environmental proteomics and metagenomics in combination with cultivation experiments and biochemical characterizations to investigate the molecular details of in situ polysaccharide degradation mechanisms during microalgal blooms. For this, we use laminarin as a model polysaccharide. Laminarin is a ubiquitous marine storage polymer of marine microalgae and is particularly abundant during phytoplankton blooms. In this study, we show that highly specialized bacterial strains of the Bacteroidetes phylum repeatedly reached high abundances during North Sea algal blooms and dominated laminarin turnover. These genomically streamlined bacteria of the genus Formosa have an expanded set of laminarin hydrolases and transporters that belonged to the most abundant proteins in the environmental samples. In vitro experiments with cultured isolates allowed us to determine the functions of in situ expressed key enzymes and to confirm their role in laminarin utilization. It is shown that laminarin consumption of Formosa spp. is paralleled by enhanced uptake of diatom-derived peptides. This study reveals that genome reduction, enzyme fusions, transporters, and enzyme expansion as well as a tight coupling of carbon and nitrogen metabolism provide the tools, which make Formosa spp. so competitive during microalgal blooms.
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80
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Taylor RR, Filia A, Paredes U, Asai Y, Holt JR, Lovett M, Forge A. Regenerating hair cells in vestibular sensory epithelia from humans. eLife 2018; 7:34817. [PMID: 30019672 PMCID: PMC6078492 DOI: 10.7554/elife.34817] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 07/16/2018] [Indexed: 01/28/2023] Open
Abstract
Human vestibular sensory epithelia in explant culture were incubated in gentamicin to ablate hair cells. Subsequent transduction of supporting cells with ATOH1 using an Ad-2 viral vector resulted in generation of highly significant numbers of cells expressing the hair cell marker protein myosin VIIa. Cells expressing myosin VIIa were also generated after blocking the Notch signalling pathway with TAPI-1 but less efficiently. Transcriptomic analysis following ATOH1 transduction confirmed up-regulation of 335 putative hair cell marker genes, including several downstream targets of ATOH1. Morphological analysis revealed numerous cells bearing dense clusters of microvilli at the apical surfaces which showed some hair cell-like characteristics confirming a degree of conversion of supporting cells. However, no cells bore organised hair bundles and several expected hair cell markers genes were not expressed suggesting incomplete differentiation. Nevertheless, the results show a potential to induce conversion of supporting cells in the vestibular sensory tissues of humans. The inner ear contains our balance system (the vestibular system) and our hearing organ (the cochlea). Their sensing units, the hair cells, detect movement or sound waves. A loss of hair cells is a major cause of inner ear disorders, such as dizziness, imbalance and deafness. When hair cells die, supporting cells that surround them close the ‘wound’ to repair the tissue. In fish, amphibians, reptiles and birds, the supporting cells can replace lost hair cells, but in mammals – including humans – hair cells are unable to regenerate in the cochlea, so hearing loss is permanent. However, previous research has shown that in certain mammals, spontaneous replacement of lost hair cells in the vestibular system can occur, but not enough to lead to a full recovery. Scientists have been able to convert supporting cells in the vestibular system of mice into hair cells by using either certain chemicals, or by introducing a specific gene into the supporting cells. In the mouse embryo, this gene, called Atoh1, switches on a signalling pathway in the inner ear, through which a non-specialised precursor cell becomes a hair cell. Inducing hair cell regeneration could be a therapy for inner ear disorders. Therefore, Taylor et al. wanted to find out if such procedures would work in inner ear tissue from humans. The researchers collected intact tissue samples from the vestibular system of patients who had undergone surgery to have a tumour removed, which would normally destroy the inner ear. All existing hair cells were removed so that mainly supporting cells remained. Then, the tissue was either treated with chemicals that increased the production of hair cells or received the gene ATOH1. The results showed that the cells containing the gene were able to develop many features characteristic of hair cells. And a smaller number of hair cells treated with the chemicals also started to develop hair cell-like features. A gene analysis after the ATOH1 transfer revealed a number of active genes known to be markers of hair cells, but also several inactive ones. This suggests that additional factors are necessary for generating fully functional hair cells. Dizziness and balance disorders present a major health care burden, particularly in the elderly population. Yet, they are often disregarded and overlooked. This study suggests that hair cell regeneration could be a feasible therapy for some forms of balance disorders linked to loss of vestibular hair cells. More research is needed to identify the other factors at play to test if hair cell regeneration in the cochlea could be used to treat hearing impairment.
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Affiliation(s)
| | - Anastasia Filia
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ursula Paredes
- UCL Ear Institute, University College London, London, United Kingdom
| | - Yukako Asai
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, United States
| | - Jeffrey R Holt
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, United States
| | - Michael Lovett
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Andrew Forge
- UCL Ear Institute, University College London, London, United Kingdom
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81
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Mass spectrometry quantitation of proteins from small pools of developing auditory and vestibular cells. Sci Data 2018; 5:180128. [PMID: 30015805 PMCID: PMC6049031 DOI: 10.1038/sdata.2018.128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/20/2018] [Indexed: 01/15/2023] Open
Abstract
Hair cells of the inner ear undergo postnatal development that leads to formation of their sensory organelles, synaptic machinery, and in the case of cochlear outer hair cells, their electromotile mechanism. To examine how the proteome changes over development from postnatal days 0 through 7, we isolated pools of 5000 Pou4f3-Gfp positive or negative cells from the cochlea or utricles; these cell pools were analysed by data-dependent and data-independent acquisition (DDA and DIA) mass spectrometry. DDA data were used to generate spectral libraries, which enabled identification and accurate quantitation of specific proteins using the DIA datasets. DIA measurements were extremely sensitive; we were able to detect proteins present at less than one part in 100,000 from only 312 hair cells. The DDA and DIA datasets will be valuable for accurately quantifying proteins in hair cells and non-hair cells over this developmental window.
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82
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Sidorenko SV, Ziganshin RH, Luneva OG, Deev LI, Alekseeva NV, Maksimov GV, Grygorczyk R, Orlov SN. Proteomics-based identification of hypoxia-sensitive membrane-bound proteins in rat erythrocytes. J Proteomics 2018; 184:25-33. [DOI: 10.1016/j.jprot.2018.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 12/25/2022]
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83
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Ellwanger DC, Scheibinger M, Dumont RA, Barr-Gillespie PG, Heller S. Transcriptional Dynamics of Hair-Bundle Morphogenesis Revealed with CellTrails. Cell Rep 2018; 23:2901-2914.e13. [PMID: 29874578 PMCID: PMC6089258 DOI: 10.1016/j.celrep.2018.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 03/19/2018] [Accepted: 05/01/2018] [Indexed: 11/30/2022] Open
Abstract
Protruding from the apical surface of inner ear sensory cells, hair bundles carry out mechanotransduction. Bundle growth involves sequential and overlapping cellular processes, which are concealed within gene expression profiles of individual cells. To dissect such processes, we developed CellTrails, a tool for uncovering, analyzing, and visualizing single-cell gene-expression dynamics. Utilizing quantitative gene-expression data for key bundle proteins from single cells of the developing chick utricle, we reconstructed de novo a bifurcating trajectory that spanned from progenitor cells to mature striolar and extrastriolar hair cells. Extraction and alignment of developmental trails and association of pseudotime with bundle length measurements linked expression dynamics of individual genes with bundle growth stages. Differential trail analysis revealed high-resolution dynamics of transcripts that control striolar and extrastriolar bundle development, including those that encode proteins that regulate [Ca2+]i or mediate crosslinking and lengthening of actin filaments.
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Affiliation(s)
- Daniel C Ellwanger
- Department of Otolaryngology, Head & Neck Surgery and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mirko Scheibinger
- Department of Otolaryngology, Head & Neck Surgery and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rachel A Dumont
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Stefan Heller
- Department of Otolaryngology, Head & Neck Surgery and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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84
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Tracing Actin Filament Bundles in Three-Dimensional Electron Tomography Density Maps of Hair Cell Stereocilia. Molecules 2018; 23:molecules23040882. [PMID: 29641472 PMCID: PMC6017643 DOI: 10.3390/molecules23040882] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/14/2018] [Accepted: 03/22/2018] [Indexed: 12/20/2022] Open
Abstract
Cryo-electron tomography (cryo-ET) is a powerful method of visualizing the three-dimensional organization of supramolecular complexes, such as the cytoskeleton, in their native cell and tissue contexts. Due to its minimal electron dose and reconstruction artifacts arising from the missing wedge during data collection, cryo-ET typically results in noisy density maps that display anisotropic XY versus Z resolution. Molecular crowding further exacerbates the challenge of automatically detecting supramolecular complexes, such as the actin bundle in hair cell stereocilia. Stereocilia are pivotal to the mechanoelectrical transduction process in inner ear sensory epithelial hair cells. Given the complexity and dense arrangement of actin bundles, traditional approaches to filament detection and tracing have failed in these cases. In this study, we introduce BundleTrac, an effective method to trace hundreds of filaments in a bundle. A comparison between BundleTrac and manually tracing the actin filaments in a stereocilium showed that BundleTrac accurately built 326 of 330 filaments (98.8%), with an overall cross-distance of 1.3 voxels for the 330 filaments. BundleTrac is an effective semi-automatic modeling approach in which a seed point is provided for each filament and the rest of the filament is computationally identified. We also demonstrate the potential of a denoising method that uses a polynomial regression to address the resolution and high-noise anisotropic environment of the density map.
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85
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ELMOD1 Stimulates ARF6-GTP Hydrolysis to Stabilize Apical Structures in Developing Vestibular Hair Cells. J Neurosci 2017; 38:843-857. [PMID: 29222402 DOI: 10.1523/jneurosci.2658-17.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/21/2017] [Accepted: 11/30/2017] [Indexed: 11/21/2022] Open
Abstract
Sensory hair cells require control of physical properties of their apical plasma membranes for normal development and function. Members of the ADP-ribosylation factor (ARF) small GTPase family regulate membrane trafficking and cytoskeletal assembly in many cells. We identified ELMO domain-containing protein 1 (ELMOD1), a guanine nucleoside triphosphatase activating protein (GAP) for ARF6, as the most highly enriched ARF regulator in hair cells. To characterize ELMOD1 control of trafficking, we analyzed mice of both sexes from a strain lacking functional ELMOD1 [roundabout (rda)]. In rda/rda mice, cuticular plates of utricle hair cells initially formed normally, then degenerated after postnatal day 5; large numbers of vesicles invaded the compromised cuticular plate. Hair bundles initially developed normally, but the cell's apical membrane lifted away from the cuticular plate, and stereocilia elongated and fused. Membrane trafficking in type I hair cells, measured by FM1-43 dye labeling, was altered in rda/rda mice. Consistent with the proposed GAP role for ELMOD1, the ARF6 GTP/GDP ratio was significantly elevated in rda/rda utricles compared with controls, and the level of ARF6-GTP was correlated with the severity of the rda/rda phenotype. These results suggest that conversion of ARF6 to its GDP-bound form is necessary for final stabilization of the hair bundle.SIGNIFICANCE STATEMENT Assembly of the mechanically sensitive hair bundle of sensory hair cells requires growth and reorganization of apical actin and membrane structures. Hair bundles and apical membranes in mice with mutations in the Elmod1 gene degenerate after formation, suggesting that the ELMOD1 protein stabilizes these structures. We show that ELMOD1 is a GTPase-activating protein in hair cells for the small GTP-binding protein ARF6, known to participate in actin assembly and membrane trafficking. We propose that conversion of ARF6 into the GDP-bound form in the apical domain of hair cells is essential for stabilizing apical actin structures like the hair bundle and ensuring that the apical membrane forms appropriately around the stereocilia.
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86
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Tompkins N, Spinelli KJ, Choi D, Barr-Gillespie PG. A Model for Link Pruning to Establish Correctly Polarized and Oriented Tip Links in Hair Bundles. Biophys J 2017; 113:1868-1881. [PMID: 29045880 DOI: 10.1016/j.bpj.2017.08.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/14/2017] [Accepted: 08/21/2017] [Indexed: 10/18/2022] Open
Abstract
Tip links are thought to gate the mechanically sensitive transduction channels of hair cells, but how they form during development and regeneration remains mysterious. In particular, it is unclear how tip links are strung between stereocilia so that they are oriented parallel to a single axis; why their polarity is uniform despite their constituent molecules' intrinsic asymmetry; and why only a single tip link is present at each tip-link position. We present here a series of simple rules that reasonably explain why these phenomena occur. In particular, our model relies on each of the two ends of the tip link having distinct Ca2+-dependent stability and being connected to different motor complexes. A simulation employing these rules allowed us to explore the parameter space for the model, demonstrating the importance of the feedback between transduction channels and angled links, links that are 60° off-axis with respect to mature tip links. We tested this key aspect of the model by examining angled links in chick cochlea hair cells. As implied by the assumptions used to generate the model, we found that angled links were stabilized if there was no tip link at the tip of the upper stereocilium, and appeared when transduction channels were blocked. The model thus plausibly explains how tip-link formation and pruning can occur.
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Affiliation(s)
- Nathan Tompkins
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, Oregon
| | - Kateri J Spinelli
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, Oregon
| | - Dongseok Choi
- School of Public Health, Oregon Health and Science University, Portland, Oregon; Graduate School of Dentistry, Kyung Hee University, Seoul, South Korea
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, Oregon.
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87
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Avenarius MR, Krey JF, Dumont RA, Morgan CP, Benson CB, Vijayakumar S, Cunningham CL, Scheffer DI, Corey DP, Müller U, Jones SM, Barr-Gillespie PG. Heterodimeric capping protein is required for stereocilia length and width regulation. J Cell Biol 2017; 216:3861-3881. [PMID: 28899994 PMCID: PMC5674897 DOI: 10.1083/jcb.201704171] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/21/2017] [Accepted: 08/08/2017] [Indexed: 02/07/2023] Open
Abstract
Control of the dimensions of actin-rich processes like filopodia, lamellipodia, microvilli, and stereocilia requires the coordinated activity of many proteins. Each of these actin structures relies on heterodimeric capping protein (CAPZ), which blocks actin polymerization at barbed ends. Because dimension control of the inner ear's stereocilia is particularly precise, we studied the CAPZB subunit in hair cells. CAPZB, present at ∼100 copies per stereocilium, concentrated at stereocilia tips as hair cell development progressed, similar to the CAPZB-interacting protein TWF2. We deleted Capzb specifically in hair cells using Atoh1-Cre, which eliminated auditory and vestibular function. Capzb-null stereocilia initially developed normally but later shortened and disappeared; surprisingly, stereocilia width decreased concomitantly with length. CAPZB2 expressed by in utero electroporation prevented normal elongation of vestibular stereocilia and irregularly widened them. Together, these results suggest that capping protein participates in stereocilia widening by preventing newly elongating actin filaments from depolymerizing.
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Affiliation(s)
- Matthew R. Avenarius
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Jocelyn F. Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Rachel A. Dumont
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Clive P. Morgan
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Connor B. Benson
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Sarath Vijayakumar
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | | | | | - David P. Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA
| | - Ulrich Müller
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD
| | - Sherri M. Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | - Peter G. Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR,Correspondence to Peter G. Barr-Gillespie:
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88
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Vogl C, Butola T, Haag N, Hausrat TJ, Leitner MG, Moutschen M, Lefèbvre PP, Speckmann C, Garrett L, Becker L, Fuchs H, Hrabe de Angelis M, Nietzsche S, Kessels MM, Oliver D, Kneussel M, Kilimann MW, Strenzke N. The BEACH protein LRBA is required for hair bundle maintenance in cochlear hair cells and for hearing. EMBO Rep 2017; 18:2015-2029. [PMID: 28893864 DOI: 10.15252/embr.201643689] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 07/27/2017] [Accepted: 08/07/2017] [Indexed: 12/15/2022] Open
Abstract
Lipopolysaccharide-responsive beige-like anchor protein (LRBA) belongs to the enigmatic class of BEACH domain-containing proteins, which have been attributed various cellular functions, typically involving intracellular protein and membrane transport processes. Here, we show that LRBA deficiency in mice leads to progressive sensorineural hearing loss. In LRBA knockout mice, inner and outer hair cell stereociliary bundles initially develop normally, but then partially degenerate during the second postnatal week. LRBA deficiency is associated with a reduced abundance of radixin and Nherf2, two adaptor proteins, which are important for the mechanical stability of the basal taper region of stereocilia. Our data suggest that due to the loss of structural integrity of the central parts of the hair bundle, the hair cell receptor potential is reduced, resulting in a loss of cochlear sensitivity and functional loss of the fraction of spiral ganglion neurons with low spontaneous firing rates. Clinical data obtained from two human patients with protein-truncating nonsense or frameshift mutations suggest that LRBA deficiency may likewise cause syndromic sensorineural hearing impairment in humans, albeit less severe than in our mouse model.
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Affiliation(s)
- Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tanvi Butola
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max-Planck-Institute for Biophysical Chemistry Göttingen, Göttingen, Germany
| | - Natja Haag
- Institute for Biochemistry I, University Hospital Jena, Jena, Germany
| | - Torben J Hausrat
- Department for Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Michael G Leitner
- Department of Physiology, Philipps University Marburg, Marburg, Germany
| | - Michel Moutschen
- Department of Immunology and Infectious Diseases, University of Liège CHU Liège, Liège, Belgium
| | - Philippe P Lefèbvre
- Department of Otorhinolaryngology, University of Liège CHU Liège, Liège, Belgium
| | - Carsten Speckmann
- Division of Pediatric Hematology and Oncology, Center for Chronic Immunodeficiency and Department of Pediatrics and Adolescent Medicine, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lillian Garrett
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany.,Institute of Developmental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany
| | - Lore Becker
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, München, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | | | - Michael M Kessels
- Institute for Biochemistry I, University Hospital Jena, Jena, Germany
| | - Dominik Oliver
- Department of Physiology, Philipps University Marburg, Marburg, Germany
| | - Matthias Kneussel
- Department for Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Manfred W Kilimann
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany.,Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Nicola Strenzke
- Auditory Systems Physiology Group Department of Otolaryngology University Medical Center Göttingen, Göttingen, Germany
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89
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Corey DP, Ó Maoiléidigh D, Ashmore JF. Mechanical Transduction Processes in the Hair Cell. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-3-319-52073-5_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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90
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Neuroplastin Isoform Np55 Is Expressed in the Stereocilia of Outer Hair Cells and Required for Normal Outer Hair Cell Function. J Neurosci 2017; 36:9201-16. [PMID: 27581460 DOI: 10.1523/jneurosci.0093-16.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 07/14/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Neuroplastin (Nptn) is a member of the Ig superfamily and is expressed in two isoforms, Np55 and Np65. Np65 regulates synaptic transmission but the function of Np55 is unknown. In an N-ethyl-N-nitrosaurea mutagenesis screen, we have now generated a mouse line with an Nptn mutation that causes deafness. We show that Np55 is expressed in stereocilia of outer hair cells (OHCs) but not inner hair cells and affects interactions of stereocilia with the tectorial membrane. In vivo vibrometry demonstrates that cochlear amplification is absent in Nptn mutant mice, which is consistent with the failure of OHC stereocilia to maintain stable interactions with the tectorial membrane. Hair bundles show morphological defects as the mutant mice age and while mechanotransduction currents can be evoked in early postnatal hair cells, cochlea microphonics recordings indicate that mechanontransduction is affected as the mutant mice age. We thus conclude that differential splicing leads to functional diversification of Nptn, where Np55 is essential for OHC function, while Np65 is implicated in the regulation of synaptic function. SIGNIFICANCE STATEMENT Amplification of input sound signals, which is needed for the auditory sense organ to detect sounds over a wide intensity range, depends on mechanical coupling of outer hair cells to the tectorial membrane. The current study shows that neuroplastin, a member of the Ig superfamily, which has previously been linked to the regulation of synaptic plasticity, is critical to maintain a stable mechanical link of outer hair cells with the tectorial membrane. In vivo recordings demonstrate that neuroplastin is essential for sound amplification and that mutation in neuroplastin leads to auditory impairment in mice.
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91
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Erickson T, Morgan CP, Olt J, Hardy K, Busch-Nentwich E, Maeda R, Clemens R, Krey JF, Nechiporuk A, Barr-Gillespie PG, Marcotti W, Nicolson T. Integration of Tmc1/2 into the mechanotransduction complex in zebrafish hair cells is regulated by Transmembrane O-methyltransferase (Tomt). eLife 2017; 6:e28474. [PMID: 28534737 PMCID: PMC5462536 DOI: 10.7554/elife.28474] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 05/20/2017] [Indexed: 01/18/2023] Open
Abstract
Transmembrane O-methyltransferase (TOMT/LRTOMT) is responsible for non-syndromic deafness DFNB63. However, the specific defects that lead to hearing loss have not been described. Using a zebrafish model of DFNB63, we show that the auditory and vestibular phenotypes are due to a lack of mechanotransduction (MET) in Tomt-deficient hair cells. GFP-tagged Tomt is enriched in the Golgi of hair cells, suggesting that Tomt might regulate the trafficking of other MET components to the hair bundle. We found that Tmc1/2 proteins are specifically excluded from the hair bundle in tomt mutants, whereas other MET complex proteins can still localize to the bundle. Furthermore, mouse TOMT and TMC1 can directly interact in HEK 293 cells, and this interaction is modulated by His183 in TOMT. Thus, we propose a model of MET complex assembly where Tomt and the Tmcs interact within the secretory pathway to traffic Tmc proteins to the hair bundle.
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Affiliation(s)
- Timothy Erickson
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Clive P Morgan
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jennifer Olt
- Department of Biomedical Science, University of Sheffield, Sheffield, United States
| | - Katherine Hardy
- Department of Biomedical Science, University of Sheffield, Sheffield, United States
| | | | - Reo Maeda
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Rachel Clemens
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jocelyn F Krey
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Alex Nechiporuk
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, United States
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, United States
| | - Teresa Nicolson
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, Portland, United States
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92
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Noumeavirus replication relies on a transient remote control of the host nucleus. Nat Commun 2017; 8:15087. [PMID: 28429720 PMCID: PMC5413956 DOI: 10.1038/ncomms15087] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/28/2017] [Indexed: 12/13/2022] Open
Abstract
Acanthamoeba are infected by a remarkable diversity of large dsDNA viruses, the infectious cycles of which have been characterized using genomics, transcriptomics and electron microscopy. Given their gene content and the persistence of the host nucleus throughout their infectious cycle, the Marseilleviridae were initially assumed to fully replicate in the cytoplasm. Unexpectedly, we find that their virions do not incorporate the virus-encoded transcription machinery, making their replication nucleus-dependent. However, instead of delivering their DNA to the nucleus, the Marseilleviridae initiate their replication by transiently recruiting the nuclear transcription machinery to their cytoplasmic viral factory. The nucleus recovers its integrity after becoming leaky at an early stage. This work highlights the importance of virion proteomic analyses to complement genome sequencing in the elucidation of the replication scheme and evolution of large dsDNA viruses. Large dsDNA viruses either replicate in or disrupt the nucleus to gain access to host RNA polymerases, or they rely on virus-encoded, packaged RNA polymerases. Here, the authors show that Noumeavirus replicates in the cytoplasm and relies on a transient recruitment of nuclear proteins to initiate replication.
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93
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Global Analysis of Protein Expression of Inner Ear Hair Cells. J Neurosci 2016; 37:1320-1339. [PMID: 28039372 DOI: 10.1523/jneurosci.2267-16.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 11/29/2016] [Accepted: 12/19/2016] [Indexed: 11/21/2022] Open
Abstract
The mammalian inner ear (IE) subserves auditory and vestibular sensations via highly specialized cells and proteins. Sensory receptor hair cells (HCs) are necessary for transducing mechanical inputs and stimulating sensory neurons by using a host of known and as yet unknown protein machinery. To understand the protein composition of these unique postmitotic cells, in which irreversible protein degradation or damage can lead to impaired hearing and balance, we analyzed IE samples by tandem mass spectrometry to generate an unbiased, shotgun-proteomics view of protein identities and abundances. By using Pou4f3/eGFP-transgenic mice in which HCs express GFP driven by Pou4f3, we FACS purified a population of HCs to analyze and compare the HC proteome with other IE subproteomes from sensory epithelia and whole IE. We show that the mammalian HC proteome comprises hundreds of uniquely or highly expressed proteins. Our global proteomic analysis of purified HCs extends the existing HC transcriptome, revealing previously undetected gene products and isoform-specific protein expression. Comparison of our proteomic data with mouse and human databases of genetic auditory/vestibular impairments confirms the critical role of the HC proteome for normal IE function, providing a cell-specific pool of candidates for novel, important HC genes. Several proteins identified exclusively in HCs by proteomics and verified by immunohistochemistry map to human genetic deafness loci, potentially representing new deafness genes. SIGNIFICANCE STATEMENT Hearing and balance rely on specialized sensory hair cells (HCs) in the inner ear (IE) to convey information about sound, acceleration, and orientation to the brain. Genetically and environmentally induced perturbations to HC proteins can result in deafness and severe imbalance. We used transgenic mice with GFP-expressing HCs, coupled with FACS sorting and tandem mass spectrometry, to define the most complete HC and IE proteome to date. We show that hundreds of proteins are uniquely identified or enriched in HCs, extending previous gene expression analyses to reveal novel HC proteins and isoforms. Importantly, deafness-linked proteins were significantly enriched in HCs, suggesting that this in-depth proteomic analysis of IE sensory cells may hold potential for deafness gene discovery.
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94
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Krey JF, Krystofiak ES, Dumont RA, Vijayakumar S, Choi D, Rivero F, Kachar B, Jones SM, Barr-Gillespie PG. Plastin 1 widens stereocilia by transforming actin filament packing from hexagonal to liquid. J Cell Biol 2016; 215:467-482. [PMID: 27811163 PMCID: PMC5119939 DOI: 10.1083/jcb.201606036] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/29/2016] [Accepted: 10/11/2016] [Indexed: 11/24/2022] Open
Abstract
With their essential role in inner ear function, stereocilia of sensory hair cells demonstrate the importance of cellular actin protrusions. Actin packing in stereocilia is mediated by cross-linkers of the plastin, fascin, and espin families. Although mice lacking espin (ESPN) have no vestibular or auditory function, we found that mice that either lacked plastin 1 (PLS1) or had nonfunctional fascin 2 (FSCN2) had reduced inner ear function, with double-mutant mice most strongly affected. Targeted mass spectrometry indicated that PLS1 was the most abundant cross-linker in vestibular stereocilia and the second most abundant protein overall; ESPN only accounted for ∼15% of the total cross-linkers in bundles. Mouse utricle stereocilia lacking PLS1 were shorter and thinner than wild-type stereocilia. Surprisingly, although wild-type stereocilia had random liquid packing of their actin filaments, stereocilia lacking PLS1 had orderly hexagonal packing. Although all three cross-linkers are required for stereocilia structure and function, PLS1 biases actin toward liquid packing, which allows stereocilia to grow to a greater diameter.
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Affiliation(s)
- Jocelyn F Krey
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239
| | - Evan S Krystofiak
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892
| | - Rachel A Dumont
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239
| | - Sarath Vijayakumar
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Dongseok Choi
- Oregon Health and Science University-Portland State University School of Public Health, Oregon Health and Science University, Portland, OR 97239
- Graduate School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Francisco Rivero
- Centre for Cardiovascular and Metabolic Research, The Hull York Medical School, University of Hull, Hull HU6 7RX, England, UK
| | - Bechara Kachar
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892
| | - Sherri M Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239
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95
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Hoffmann TJ, Keats BJ, Yoshikawa N, Schaefer C, Risch N, Lustig LR. A Large Genome-Wide Association Study of Age-Related Hearing Impairment Using Electronic Health Records. PLoS Genet 2016; 12:e1006371. [PMID: 27764096 PMCID: PMC5072625 DOI: 10.1371/journal.pgen.1006371] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/16/2016] [Indexed: 01/22/2023] Open
Abstract
Age-related hearing impairment (ARHI), one of the most common sensory disorders, can be mitigated, but not cured or eliminated. To identify genetic influences underlying ARHI, we conducted a genome-wide association study of ARHI in 6,527 cases and 45,882 controls among the non-Hispanic whites from the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort. We identified two novel genome-wide significant SNPs: rs4932196 (odds ratio = 1.185, p = 4.0x10-11), 52Kb 3’ of ISG20, which replicated in a meta-analysis of the other GERA race/ethnicity groups (1,025 cases, 12,388 controls, p = 0.00094) and in a UK Biobank case-control analysis (30,802 self-reported cases, 78,586 controls, p = 0.015); and rs58389158 (odds ratio = 1.132, p = 1.8x10-9), which replicated in the UK Biobank (p = 0.00021). The latter SNP lies just outside exon 8 and is highly correlated (r2 = 0.96) with the missense SNP rs5756795 in exon 7 of TRIOBP, a gene previously associated with prelingual nonsyndromic hearing loss. We further tested these SNPs in phenotypes from audiologist notes available on a subset of GERA (4,903 individuals), stratified by case/control status, to construct an independent replication test, and found a significant effect of rs58389158 on speech reception threshold (SRT; overall GERA meta-analysis p = 1.9x10-6). We also tested variants within exons of 132 other previously-identified hearing loss genes, and identified two common additional significant SNPs: rs2877561 (synonymous change in ILDR1, p = 6.2x10-5), which replicated in the UK Biobank (p = 0.00057), and had a significant GERA SRT (p = 0.00019) and speech discrimination score (SDS; p = 0.0019); and rs9493627 (missense change in EYA4, p = 0.00011) which replicated in the UK Biobank (p = 0.0095), other GERA groups (p = 0.0080), and had a consistent significant result for SRT (p = 0.041) and suggestive result for SDS (p = 0.081). Large cohorts with GWAS data and electronic health records may be a useful method to characterize the genetic architecture of ARHI. Age-related hearing impairment (ARHI) is one of the most common sensory disorders. While ARHI effects can be mitigated with current technologies, it cannot be cured or eliminated. It is thus hoped that identification of genetic influences on ARHI may one day lead to curative therapies. Towards this goal, the current study utilized electronic health record data from non-Hispanic whites in the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort to conduct a genome-wide association study of ARHI, and tested the significant variants for replication in other GERA race/ethnicity groups, independent GERA phenotypes, and self-reported ARHI from the UK Biobank. We discovered two genome-wide significant SNPs. The first was novel and near ISG20. The second was in TRIOBP, a gene previously associated with prelingual nonsyndromic hearing loss. Motivated by our TRIOBP results, we also looked at exons in known hearing loss genes, and identified two additional SNPs, rs2877561 in ILDR1 and rs9493672 in EYA4 (at a significance threshold adjusted for number of SNPs in those regions). These results suggest that large cohorts with GWAS data and electronic health records may be a useful method to characterize the genetic architecture of ARHI.
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Affiliation(s)
- Thomas J. Hoffmann
- Department of Epidemiology and Biostatistics, and Institute for Human Genetics, University of California San Francisco, San Francisco, United States of America
- * E-mail:
| | - Bronya J. Keats
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, United States of America
| | - Noriko Yoshikawa
- Department of Head and Neck Surgery, Kaiser Permanente Medical Center, Oakland, United States of America
| | - Catherine Schaefer
- Kaiser Permanente Northern California Division of Research, Oakland, United States of America
| | - Neil Risch
- Department of Epidemiology and Biostatistics, and Institute for Human Genetics, University of California San Francisco, San Francisco, United States of America
- Kaiser Permanente Northern California Division of Research, Oakland, United States of America
| | - Lawrence R. Lustig
- Department of Otolaryngology—Head and Neck Surgery, Columbia University Medical Center, Columbia, United States of America
- New York Presbyterian Hospital, New York, United States of America
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96
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Krey JF, Wilmarth PA, David LL, Barr-Gillespie PG. Analysis of the Proteome of Hair-Cell Stereocilia by Mass Spectrometry. Methods Enzymol 2016; 585:329-354. [PMID: 28109437 DOI: 10.1016/bs.mie.2016.09.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Characterization of proteins that mediate mechanotransduction by hair cells, the sensory cells of the inner ear, is hampered by the scarcity of these cells and their sensory organelle, the hair bundle. Mass spectrometry, with its high sensitivity and identification precision, is the ideal method for determining which proteins are present in bundles and what proteins they interact with. We describe here the isolation of mouse hair bundles, as well as preparation of bundle protein samples for mass spectrometry. We also describe protocols for data-dependent (shotgun) and parallel reaction monitoring (targeted) mass spectrometry that allow us to identify and quantify proteins of the hair bundle. These sensitive methods are particularly useful for comparing proteomes of wild-type mice and mice with deafness mutations affecting hair-bundle proteins.
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Affiliation(s)
- J F Krey
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States; Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - P A Wilmarth
- Oregon Health & Science University, Portland, OR, United States
| | - L L David
- Oregon Health & Science University, Portland, OR, United States
| | - P G Barr-Gillespie
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States; Vollum Institute, Oregon Health & Science University, Portland, OR, United States; Oregon Health & Science University, Portland, OR, United States.
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97
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Winkelman JD, Suarez C, Hocky GM, Harker AJ, Morganthaler AN, Christensen JR, Voth GA, Bartles JR, Kovar DR. Fascin- and α-Actinin-Bundled Networks Contain Intrinsic Structural Features that Drive Protein Sorting. Curr Biol 2016; 26:2697-2706. [PMID: 27666967 DOI: 10.1016/j.cub.2016.07.080] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/04/2016] [Accepted: 07/28/2016] [Indexed: 12/25/2022]
Abstract
Cells assemble and maintain functionally distinct actin cytoskeleton networks with various actin filament organizations and dynamics through the coordinated action of different sets of actin-binding proteins. The biochemical and functional properties of diverse actin-binding proteins, both alone and in combination, have been increasingly well studied. Conversely, how different sets of actin-binding proteins properly sort to distinct actin filament networks in the first place is not nearly as well understood. Actin-binding protein sorting is critical for the self-organization of diverse dynamic actin cytoskeleton networks within a common cytoplasm. Using in vitro reconstitution techniques including biomimetic assays and single-molecule multi-color total internal reflection fluorescence microscopy, we discovered that sorting of the prominent actin-bundling proteins fascin and α-actinin to distinct networks is an intrinsic behavior, free of complicated cellular signaling cascades. When mixed, fascin and α-actinin mutually exclude each other by promoting their own recruitment and inhibiting recruitment of the other, resulting in the formation of distinct fascin- or α-actinin-bundled domains. Subdiffraction-resolution light microscopy and negative-staining electron microscopy revealed that fascin domains are densely packed, whereas α-actinin domains consist of widely spaced parallel actin filaments. Importantly, other actin-binding proteins such as fimbrin and espin show high specificity between these two bundle types within the same reaction. Here we directly observe that fascin and α-actinin intrinsically segregate to discrete bundled domains that are specifically recognized by other actin-binding proteins.
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Affiliation(s)
- Jonathan D Winkelman
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Glen M Hocky
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Alyssa J Harker
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Alisha N Morganthaler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jenna R Christensen
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Gregory A Voth
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Computation Institute, The University of Chicago, Chicago, IL 60637, USA
| | - James R Bartles
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA.
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98
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McGrath J, Roy P, Perrin BJ. Stereocilia morphogenesis and maintenance through regulation of actin stability. Semin Cell Dev Biol 2016; 65:88-95. [PMID: 27565685 DOI: 10.1016/j.semcdb.2016.08.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/09/2016] [Accepted: 08/22/2016] [Indexed: 12/24/2022]
Abstract
Stereocilia are actin-based protrusions on auditory and vestibular sensory cells that are required for hearing and balance. They convert physical force from sound, head movement or gravity into an electrical signal, a process that is called mechanoelectrical transduction. This function depends on the ability of sensory cells to grow stereocilia of defined lengths. These protrusions form a bundle with a highly precise geometry that is required to detect nanoscale movements encountered in the inner ear. Congenital or progressive stereocilia degeneration causes hearing loss. Thus, understanding stereocilia hair bundle structure, development, and maintenance is pivotal to understanding the pathogenesis of deafness. Stereocilia cores are made from a tightly packed array of parallel, crosslinked actin filaments, the length and stability of which are regulated in part by myosin motors, actin crosslinkers and capping proteins. This review aims to describe stereocilia actin regulation in the context of an emerging "tip turnover" model where actin assembles and disassembles at stereocilia tips while the remainder of the core is exceptionally stable.
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Affiliation(s)
- Jamis McGrath
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46022, USA
| | - Pallabi Roy
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46022, USA
| | - Benjamin J Perrin
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46022, USA.
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Morgan CP, Krey JF, Grati M, Zhao B, Fallen S, Kannan-Sundhari A, Liu XZ, Choi D, Müller U, Barr-Gillespie PG. PDZD7-MYO7A complex identified in enriched stereocilia membranes. eLife 2016; 5:e18312. [PMID: 27525485 PMCID: PMC5005036 DOI: 10.7554/elife.18312] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/14/2016] [Indexed: 12/15/2022] Open
Abstract
While more than 70 genes have been linked to deafness, most of which are expressed in mechanosensory hair cells of the inner ear, a challenge has been to link these genes into molecular pathways. One example is Myo7a (myosin VIIA), in which deafness mutations affect the development and function of the mechanically sensitive stereocilia of hair cells. We describe here a procedure for the isolation of low-abundance protein complexes from stereocilia membrane fractions. Using this procedure, combined with identification and quantitation of proteins with mass spectrometry, we demonstrate that MYO7A forms a complex with PDZD7, a paralog of USH1C and DFNB31. MYO7A and PDZD7 interact in tissue-culture cells, and co-localize to the ankle-link region of stereocilia in wild-type but not Myo7a mutant mice. Our data thus describe a new paradigm for the interrogation of low-abundance protein complexes in hair cell stereocilia and establish an unanticipated link between MYO7A and PDZD7.
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Affiliation(s)
- Clive P Morgan
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jocelyn F Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
| | - M'hamed Grati
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
| | - Bo Zhao
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, United States
| | - Shannon Fallen
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
| | | | - Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
| | - Dongseok Choi
- OHSU-PSU School of Public Health, Oregon Health and Science University, Portland, United States
- Graduate School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Ulrich Müller
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, United States
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
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100
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Tyska MJ. Listen to your gut: Using adhesion to shape the surface of functionally diverse epithelia. Rare Dis 2016. [DOI: 10.1080/21675511.2016.1220469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
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