1
|
Kwan GT, Andrade LR, Prime KJ, Tresguerres M. Immunohistochemical and ultrastructural characterization of the inner ear epithelial cells of splitnose rockfish ( Sebastes diploproa). Am J Physiol Regul Integr Comp Physiol 2024; 326:R277-R296. [PMID: 38189166 DOI: 10.1152/ajpregu.00223.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/01/2023] [Accepted: 01/01/2024] [Indexed: 01/09/2024]
Abstract
The inner ear of teleost fish regulates the ionic and acid-base chemistry and secretes protein matrix into the endolymph to facilitate otolith biomineralization, which is used to maintain vestibular and auditory functions. The otolith is biomineralized in a concentric ring pattern corresponding to seasonal growth, and this calcium carbonate (CaCO3) polycrystal has become a vital aging and life-history tool for fishery managers, ecologists, and conservation biologists. Moreover, biomineralization patterns are sensitive to environmental variability including climate change, thereby threatening the accuracy and relevance of otolith-reliant toolkits. However, the cellular biology of the inner ear is poorly characterized, which is a hurdle for a mechanistic understanding of the underlying processes. This study provides a systematic characterization of the cell types in the inner ear of splitnose rockfish (Sebastes diploproa). Scanning electron microscopy revealed the apical morphologies of six inner ear cell types. In addition, immunostaining and confocal microscopy characterized the expression and subcellular localization of the proteins Na+-K+-ATPase, carbonic anhydrase, V-type H+-ATPase, Na+-K+-2Cl--cotransporter, otolith matrix protein 1, and otolin-1 in six inner ear cell types bordering the endolymph. This fundamental cytological characterization of the rockfish inner ear epithelium illustrates the intricate physiological processes involved in otolith biomineralization and highlights how greater mechanistic understanding is necessary to predict their multistressor responses to future climate change.
Collapse
Affiliation(s)
- Garfield T Kwan
- Wildlife, Fish and Conservation Biology, University of California Davis, Davis, California, United States
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States
| | - Leonardo R Andrade
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, United States
| | - Kaelan J Prime
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States
| | - Martin Tresguerres
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States
| |
Collapse
|
2
|
Zuo Y, Ren Y, Pei Y, Aioub AAA, Hu Z. Effects of periplocoside T isolated from Periploca sepium on behavior and sensory-CNS-motor circuits in Drosophila melanogaster larvae. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 191:105365. [PMID: 36963935 DOI: 10.1016/j.pestbp.2023.105365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/29/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
Periplocoside T (PST) from Periploca sepium has insecticidal activity against some lepidopterans, which can significantly inhibit the activity of vacuolar-type H+-ATPases (V-ATPase). V-ATPase is involved in the release of neurotransmitters in vesicles during nerve signal transduction. However, there are actions of PST on behavior and sensory-central nervous system (CNS)-motor neural circuit which are commonly overlooked. After exposure to 500 mg/L PST for 48 h, the difference of the proportion of larvae responding to stimuli in the four Drosophila strains was not significant as compared to controls, but larval mouth hook movement and body wall motion were significantly decreased as compared to controls, and the decrease was more obvious in parats1; DSC1-/- and DSC1-/- strains, especially in parats1; DSC1-/- strain. Compared with control (DMSO), the excitatory junction potential (EJP) frequencies of sensory-CNS-motor circuits in the four Drosophila strains after PST or bafiloymcin A1 (BA1, a V-ATPase specific inhibitor) treatment gradually decreased with time, and the decreasing amplitude of BA1 treatment was greater than that of PST treatment, but both were higher than that of the control. The decay amplitude of EJP frequency in two strains with DSC1 channel knockout was lower than that of w1118 and parats1 strains without DSC1 channel knockout. Thus, the results indicated that PST, similar to BA1, could inhibit the transmission of sensory-CNS-motor circuit excitability of Drosophila larvae by inhibiting the activity of V-ATPase, and DSC1 channel play a role of in regulating the stability of nervous system.
Collapse
Affiliation(s)
- Yayun Zuo
- Institute of Pesticide Science, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory for Botanical Pesticide R & D of Shaanxi Province, Yangling, Shaanxi 712100, China
| | - Yaxin Ren
- Institute of Pesticide Science, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory for Botanical Pesticide R & D of Shaanxi Province, Yangling, Shaanxi 712100, China
| | - Yakun Pei
- Institute of Pesticide Science, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory for Botanical Pesticide R & D of Shaanxi Province, Yangling, Shaanxi 712100, China
| | - Ahmed A A Aioub
- Plant Protection Department, Faculty of Agriculture, Zagazig University, 44511 Zagazig, Egypt
| | - Zhaonong Hu
- Institute of Pesticide Science, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory for Botanical Pesticide R & D of Shaanxi Province, Yangling, Shaanxi 712100, China; Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
| |
Collapse
|
3
|
Petrovszki P, Sebők-Nagy K, Páli T. The Activity of Native Vacuolar Proton-ATPase in an Oscillating Electric Field - Demystifying an Apparent Effect of Music on a Biomolecule. Front Mol Biosci 2021; 8:772167. [PMID: 34805280 PMCID: PMC8595334 DOI: 10.3389/fmolb.2021.772167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The effect of an oscillating electric field generated from music on yeast vacuolar proton-ATPase (V-ATPase) activity in its native environment is reported. An oscillating electric field is generated by electrodes that are immersed into a dispersion of yeast vacuolar membrane vesicles natively hosting a high concentration of active V-ATPase. The substantial difference in the ATP hydrolysing activity of V-ATPase under the most stimulating and inhibiting music is unprecedented. Since the topic, i.e., an effect of music on biomolecules, is very attractive for non-scientific, esoteric mystification, we provide a rational explanation for the observed new phenomenon. Good correlation is found between changes in the specific activity of the enzyme and the combined intensity of certain frequency bands of the Fourier spectra of the music clips. Most prominent identified frequencies are harmonically related to each other and to the estimated rotation rate of the enzyme. These results lead to the conclusion that the oscillating electric field interferes with periodic trans-membrane charge motions in the working enzyme.
Collapse
Affiliation(s)
- Pál Petrovszki
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| |
Collapse
|
4
|
Oot RA, Yao Y, Manolson MF, Wilkens S. Purification of active human vacuolar H +-ATPase in native lipid-containing nanodiscs. J Biol Chem 2021; 297:100964. [PMID: 34270960 PMCID: PMC8353480 DOI: 10.1016/j.jbc.2021.100964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/07/2021] [Accepted: 07/12/2021] [Indexed: 12/26/2022] Open
Abstract
Vacuolar H+-ATPases (V-ATPases) are large, multisubunit proton pumps that acidify the lumen of organelles in virtually every eukaryotic cell and in specialized acid-secreting animal cells, the enzyme pumps protons into the extracellular space. In higher organisms, most of the subunits are expressed as multiple isoforms, with some enriched in specific compartments or tissues and others expressed ubiquitously. In mammals, subunit a is expressed as four isoforms (a1-4) that target the enzyme to distinct biological membranes. Mutations in a isoforms are known to give rise to tissue-specific disease, and some a isoforms are upregulated and mislocalized to the plasma membrane in invasive cancers. However, isoform complexity and low abundance greatly complicate purification of active human V-ATPase, a prerequisite for developing isoform-specific therapeutics. Here, we report the purification of an active human V-ATPase in native lipid nanodiscs from a cell line stably expressing affinity-tagged a isoform 4 (a4). We find that exogenous expression of this single subunit in HEK293F cells permits assembly of a functional V-ATPase by incorporation of endogenous subunits. The ATPase activity of the preparation is >95% sensitive to concanamycin A, indicating that the lipid nanodisc-reconstituted enzyme is functionally coupled. Moreover, this strategy permits purification of the enzyme’s isolated membrane subcomplex together with biosynthetic assembly factors coiled-coil domain–containing protein 115, transmembrane protein 199, and vacuolar H+-ATPase assembly integral membrane protein 21. Our work thus lays the groundwork for biochemical characterization of active human V-ATPase in an a subunit isoform-specific manner and establishes a platform for the study of the assembly and regulation of the human holoenzyme.
Collapse
Affiliation(s)
- Rebecca A Oot
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Yeqi Yao
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Morris F Manolson
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA.
| |
Collapse
|
5
|
Downregulation of ATP6V1A Involved in Alzheimer's Disease via Synaptic Vesicle Cycle, Phagosome, and Oxidative Phosphorylation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:5555634. [PMID: 33981384 PMCID: PMC8087993 DOI: 10.1155/2021/5555634] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/02/2021] [Accepted: 03/24/2021] [Indexed: 12/12/2022]
Abstract
Objective The objective of this study was to investigate the potential molecular mechanisms of ATPase H+ transporting V1 subunit A (ATP6V1A) underlying Alzheimer's disease (AD). Methods Microarray expression data of human temporal cortex samples from the GSE118553 dataset were profiled to screen for differentially expressed genes (DEGs) between AD/control and ATP6V1A-low/high groups. Correlations of coexpression modules with AD and ATP6V1A were assessed by weight gene correlation network analysis (WGCNA). DEGs strongly interacting with ATP6V1A were extracted to construct global regulatory network. Further cross-talking pathways of ATP6V1A were identified by functional enrichment analysis. Diagnostic performance of ATP6V1A in AD prediction was evaluated using area under the curve (AUC) analysis. Results The mean expression of ATP6V1A was significantly downregulated in AD compared with nondementia controls. A total of 1,364 DEGs were overlapped from AD/control and ATP6V1A-low/high groups. Based on these DEGs, four coexpression modules were predicted by WGCNA. The blue, brown, and turquoise modules were significantly correlated with AD and low ATP6V1A, whose DEGs were enriched in phagosome, oxidative phosphorylation, synaptic vesicle cycle, focal adhesion, and gamma-aminobutyric acidergic (GABAergic) synapse. Global regulatory network was constructed to identify the cross-talking pathways of ATP6V1A, such as synaptic vesicle cycle, phagosome, and oxidative phosphorylation. According to the AUC value of 74.2%, low ATP6V1A expression accurately predicted the occurrence of AD. Conclusions Our findings highlighted the pleiotropic roles of low ATP6V1A in AD pathogenesis, possibly mediated by synaptic vesicle cycle, phagosome, and oxidative phosphorylation.
Collapse
|
6
|
Eaton AF, Merkulova M, Brown D. The H +-ATPase (V-ATPase): from proton pump to signaling complex in health and disease. Am J Physiol Cell Physiol 2020; 320:C392-C414. [PMID: 33326313 PMCID: PMC8294626 DOI: 10.1152/ajpcell.00442.2020] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A primary function of the H+-ATPase (or V-ATPase) is to create an electrochemical proton gradient across eukaryotic cell membranes, which energizes fundamental cellular processes. Its activity allows for the acidification of intracellular vesicles and organelles, which is necessary for many essential cell biological events to occur. In addition, many specialized cell types in various organ systems such as the kidney, bone, male reproductive tract, inner ear, olfactory mucosa, and more, use plasma membrane V-ATPases to perform specific activities that depend on extracellular acidification. It is, however, increasingly apparent that V-ATPases are central players in many normal and pathophysiological processes that directly influence human health in many different and sometimes unexpected ways. These include cancer, neurodegenerative diseases, diabetes, and sensory perception, as well as energy and nutrient-sensing functions within cells. This review first covers the well-established role of the V-ATPase as a transmembrane proton pump in the plasma membrane and intracellular vesicles and outlines factors contributing to its physiological regulation in different cell types. This is followed by a discussion of the more recently emerging unconventional roles for the V-ATPase, such as its role as a protein interaction hub involved in cell signaling, and the (patho)physiological implications of these interactions. Finally, the central importance of endosomal acidification and V-ATPase activity on viral infection will be discussed in the context of the current COVID-19 pandemic.
Collapse
Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
7
|
Beauregard-Lacroix E, Pacheco-Cuellar G, Ajeawung NF, Tardif J, Dieterich K, Dabir T, Vind-Kezunovic D, White SM, Zadori D, Castiglioni C, Tranebjærg L, Tørring PM, Blair E, Wisniewska M, Camurri MV, van Bever Y, Molidperee S, Taylor J, Dionne-Laporte A, Sisodiya SM, Hennekam RCM, Campeau PM. DOORS syndrome and a recurrent truncating ATP6V1B2 variant. Genet Med 2020; 23:149-154. [PMID: 32873933 DOI: 10.1038/s41436-020-00950-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Biallelic variants in TBC1D24, which encodes a protein that regulates vesicular transport, are frequently identified in patients with DOORS (deafness, onychodystrophy, osteodystrophy, intellectual disability [previously referred to as mental retardation], and seizures) syndrome. The aim of the study was to identify a genetic cause in families with DOORS syndrome and without a TBC1D24 variant. METHODS Exome or Sanger sequencing was performed in individuals with a clinical diagnosis of DOORS syndrome without TBC1D24 variants. RESULTS We identified the same truncating variant in ATP6V1B2 (NM_001693.4:c.1516C>T; p.Arg506*) in nine individuals from eight unrelated families with DOORS syndrome. This variant was already reported in individuals with dominant deafness onychodystrophy (DDOD) syndrome. Deafness was present in all individuals, along with onychodystrophy and abnormal fingers and/or toes. All families but one had developmental delay or intellectual disability and five individuals had epilepsy. We also describe two additional families with DDOD syndrome in whom the same variant was found. CONCLUSION We expand the phenotype associated with ATP6V1B2 and propose another causal gene for DOORS syndrome. This finding suggests that DDOD and DOORS syndromes might lie on a spectrum of clinically and molecularly related conditions.
Collapse
Affiliation(s)
- Eliane Beauregard-Lacroix
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Guillermo Pacheco-Cuellar
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Norbert F Ajeawung
- CHU Sainte Justine Research Center, Université de Montréal, Montreal, QC, Canada
| | - Jessica Tardif
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Klaus Dieterich
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences (GIN), Grenoble, France
| | - Tabib Dabir
- Department of Genetic Medicine, Belfast City Hospital, Belfast, Northern Ireland, UK
| | - Dina Vind-Kezunovic
- Department of Dermatology, Copenhagen University Hospital Bispebjerg, Copenhagen, NV, Denmark
| | - Susan M White
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Denes Zadori
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | | | - Lisbeth Tranebjærg
- The Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Ed Blair
- Oxford Regional Genetics Service, Oxford University Hospitals, Oxford, UK
| | - Marzena Wisniewska
- Department of Medical Genetics, Poznañ University of Medical Sciences, Poznañ, Poland
| | - Maria Vittoria Camurri
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Yolande van Bever
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sirinart Molidperee
- CHU Sainte Justine Research Center, Université de Montréal, Montreal, QC, Canada
| | - Juliet Taylor
- Genetic Health Service New Zealand-Northern Hub, Auckland, New Zealand
| | - Alexandre Dionne-Laporte
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Raoul C M Hennekam
- Department of Pediatrics, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Philippe M Campeau
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada.
| |
Collapse
|
8
|
Song Q, Meng B, Xu H, Mao Z. The emerging roles of vacuolar-type ATPase-dependent Lysosomal acidification in neurodegenerative diseases. Transl Neurodegener 2020; 9:17. [PMID: 32393395 PMCID: PMC7212675 DOI: 10.1186/s40035-020-00196-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/23/2020] [Indexed: 12/15/2022] Open
Abstract
Background Lysosomes digest extracellular material from the endocytic pathway and intracellular material from the autophagic pathway. This process is performed by the resident hydrolytic enzymes activated by the highly acidic pH within the lysosomal lumen. Lysosome pH gradients are mainly maintained by the vacuolar (H+) ATPase (or V-ATPase), which pumps protons into lysosomal lumen by consuming ATP. Dysfunction of V-ATPase affects lysosomal acidification, which disrupts the clearance of substrates and leads to many disorders, including neurodegenerative diseases. Main body As a large multi-subunit complex, the V-ATPase is composed of an integral membrane V0 domain involved in proton translocation and a peripheral V1 domain catalyzing ATP hydrolysis. The canonical functions of V-ATPase rely on its H+-pumping ability in multiple vesicle organelles to regulate endocytic traffic, protein processing and degradation, synaptic vesicle loading, and coupled transport. The other non-canonical effects of the V-ATPase that are not readily attributable to its proton-pumping activity include membrane fusion, pH sensing, amino-acid-induced activation of mTORC1, and scaffolding for protein-protein interaction. In response to various stimuli, V-ATPase complex can reversibly dissociate into V1 and V0 domains and thus close ATP-dependent proton transport. Dysregulation of pH and lysosomal dysfunction have been linked to many human diseases, including neurodegenerative disorders such as Alzheimer disease, Parkinson’s disease, amyotrophic lateral sclerosis as well as neurodegenerative lysosomal storage disorders. Conclusion V-ATPase complex is a universal proton pump and plays an important role in lysosome acidification in all types of cells. Since V-ATPase dysfunction contributes to the pathogenesis of multiple neurodegenerative diseases, further understanding the mechanisms that regulate the canonical and non-canonical functions of V-ATPase will reveal molecular details of disease process and help assess V-ATPase or molecules related to its regulation as therapeutic targets.
Collapse
Affiliation(s)
- Qiaoyun Song
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Reproductive Genetics, Hebei General Hospital, Shijiazhuang, Hebei Province, 050051, People's Republic of China.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Bo Meng
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Haidong Xu
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Zixu Mao
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA. .,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| |
Collapse
|
9
|
Roh SH, Stam NJ, Hryc CF, Couoh-Cardel S, Pintilie G, Chiu W, Wilkens S. The 3.5-Å CryoEM Structure of Nanodisc-Reconstituted Yeast Vacuolar ATPase V o Proton Channel. Mol Cell 2018. [PMID: 29526695 DOI: 10.1016/j.molcel.2018.02.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The molecular mechanism of transmembrane proton translocation in rotary motor ATPases is not fully understood. Here, we report the 3.5-Å resolution cryoEM structure of the lipid nanodisc-reconstituted Vo proton channel of the yeast vacuolar H+-ATPase, captured in a physiologically relevant, autoinhibited state. The resulting atomic model provides structural detail for the amino acids that constitute the proton pathway at the interface of the proteolipid ring and subunit a. Based on the structure and previous mutagenesis studies, we propose the chemical basis of transmembrane proton transport. Moreover, we discovered that the C terminus of the assembly factor Voa1 is an integral component of mature Vo. Voa1's C-terminal transmembrane α helix is bound inside the proteolipid ring, where it contributes to the stability of the complex. Our structure rationalizes possible mechanisms by which mutations in human Vo can result in disease phenotypes and may thus provide new avenues for therapeutic interventions.
Collapse
Affiliation(s)
- Soung-Hun Roh
- Department of Bioengineering and James H. Clark Center, Stanford University, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Nicholas J Stam
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Corey F Hryc
- Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sergio Couoh-Cardel
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Grigore Pintilie
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wah Chiu
- Department of Bioengineering and James H. Clark Center, Stanford University, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
| |
Collapse
|
10
|
Oot RA, Couoh-Cardel S, Sharma S, Stam NJ, Wilkens S. Breaking up and making up: The secret life of the vacuolar H + -ATPase. Protein Sci 2017; 26:896-909. [PMID: 28247968 DOI: 10.1002/pro.3147] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 02/21/2017] [Indexed: 01/24/2023]
Abstract
The vacuolar ATPase (V-ATPase; V1 Vo -ATPase) is a large multisubunit proton pump found in the endomembrane system of all eukaryotic cells where it acidifies the lumen of subcellular organelles including lysosomes, endosomes, the Golgi apparatus, and clathrin-coated vesicles. V-ATPase function is essential for pH and ion homeostasis, protein trafficking, endocytosis, mechanistic target of rapamycin (mTOR), and Notch signaling, as well as hormone secretion and neurotransmitter release. V-ATPase can also be found in the plasma membrane of polarized animal cells where its proton pumping function is involved in bone remodeling, urine acidification, and sperm maturation. Aberrant (hypo or hyper) activity has been associated with numerous human diseases and the V-ATPase has therefore been recognized as a potential drug target. Recent progress with moderate to high-resolution structure determination by cryo electron microscopy and X-ray crystallography together with sophisticated single-molecule and biochemical experiments have provided a detailed picture of the structure and unique mode of regulation of the V-ATPase. This review summarizes the recent advances, focusing on the structural and biophysical aspects of the field.
Collapse
Affiliation(s)
- Rebecca A Oot
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Sergio Couoh-Cardel
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Stuti Sharma
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Nicholas J Stam
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| |
Collapse
|
11
|
Kissing S, Rudnik S, Damme M, Lüllmann-Rauch R, Ichihara A, Kornak U, Eskelinen EL, Jabs S, Heeren J, De Brabander JK, Haas A, Saftig P. Disruption of the vacuolar-type H +-ATPase complex in liver causes MTORC1-independent accumulation of autophagic vacuoles and lysosomes. Autophagy 2017; 13:670-685. [PMID: 28129027 DOI: 10.1080/15548627.2017.1280216] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The vacuolar-type H+-translocating ATPase (v-H+-ATPase) has been implicated in the amino acid-dependent activation of the mechanistic target of rapamycin complex 1 (MTORC1), an important regulator of macroautophagy. To reveal the mechanistic links between the v-H+-ATPase and MTORC1, we destablilized v-H+-ATPase complexes in mouse liver cells by induced deletion of the essential chaperone ATP6AP2. ATP6AP2-mutants are characterized by massive accumulation of endocytic and autophagic vacuoles in hepatocytes. This cellular phenotype was not caused by a block in endocytic maturation or an impaired acidification. However, the degradation of LC3-II in the knockout hepatocytes appeared to be reduced. When v-H+-ATPase levels were decreased, we observed lysosome association of MTOR and normal signaling of MTORC1 despite an increase in autophagic marker proteins. To better understand why MTORC1 can be active when v-H+-ATPase is depleted, the activation of MTORC1 was analyzed in ATP6AP2-deficient fibroblasts. In these cells, very little amino acid-elicited activation of MTORC1 was observed. In contrast, insulin did induce MTORC1 activation, which still required intracellular amino acid stores. These results suggest that in vivo the regulation of macroautophagy depends not only on v-H+-ATPase-mediated regulation of MTORC1.
Collapse
Affiliation(s)
- Sandra Kissing
- a Institut für Biochemie, Christian-Albrechts-Universität zu Kiel , Germany
| | - Sönke Rudnik
- a Institut für Biochemie, Christian-Albrechts-Universität zu Kiel , Germany
| | - Markus Damme
- a Institut für Biochemie, Christian-Albrechts-Universität zu Kiel , Germany
| | | | - Atsuhiro Ichihara
- c Department of Medicine II , Tokyo Women´s Medical University , Japan
| | - Uwe Kornak
- d Institut für Medizinische Genetik und Humangenetik, Charité-Universitaetsmedizin , Berlin , Germany
| | - Eeva-Liisa Eskelinen
- e Department of Biosciences , Division of Biochemistry and Biotechnology, University of Helsinki , Finland
| | - Sabrina Jabs
- f Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC) , Berlin , Germany
| | - Jörg Heeren
- g Institut für Biochemie und Molekulare Zellbiologie, Zentrum für Experimentelle Medizin, Universitätsklinikum Hamburg-Eppendorf , Germany
| | - Jef K De Brabander
- h Department of Biochemistry , University of Texas Southwestern Medical Center , Dallas , TX , USA
| | - Albert Haas
- i Institut für Zellbiologie, Friedrich-Wilhelms Universität Bonn , Germany
| | - Paul Saftig
- a Institut für Biochemie, Christian-Albrechts-Universität zu Kiel , Germany
| |
Collapse
|
12
|
Stam NJ, Wilkens S. Structure of the Lipid Nanodisc-reconstituted Vacuolar ATPase Proton Channel: DEFINITION OF THE INTERACTION OF ROTOR AND STATOR AND IMPLICATIONS FOR ENZYME REGULATION BY REVERSIBLE DISSOCIATION. J Biol Chem 2016; 292:1749-1761. [PMID: 27965356 DOI: 10.1074/jbc.m116.766790] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/11/2016] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic vacuolar H+-ATPase (V-ATPase) is a multisubunit enzyme complex that acidifies subcellular organelles and the extracellular space. V-ATPase consists of soluble V1-ATPase and membrane-integral Vo proton channel sectors. To investigate the mechanism of V-ATPase regulation by reversible disassembly, we recently determined a cryo-EM reconstruction of yeast Vo The structure indicated that, when V1 is released from Vo, the N-terminal cytoplasmic domain of subunit a (aNT) changes conformation to bind rotor subunit d However, insufficient resolution precluded a precise definition of the aNT-d interface. Here we reconstituted Vo into lipid nanodiscs for single-particle EM. 3D reconstructions calculated at ∼15-Å resolution revealed two sites of contact between aNT and d that are mediated by highly conserved charged residues. Alanine mutagenesis of some of these residues disrupted the aNT-d interaction, as shown by isothermal titration calorimetry and gel filtration of recombinant subunits. A recent cryo-EM study of holo V-ATPase revealed three major conformations corresponding to three rotational states of the central rotor of the enzyme. Comparison of the three V-ATPase conformations with the structure of nanodisc-bound Vo revealed that Vo is halted in rotational state 3. Combined with our prior work that showed autoinhibited V1-ATPase to be arrested in state 2, we propose a model in which the conformational mismatch between free V1 and Vo functions to prevent unintended reassembly of holo V-ATPase when activity is not needed.
Collapse
Affiliation(s)
- Nicholas J Stam
- From the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210
| | - Stephan Wilkens
- From the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210.
| |
Collapse
|
13
|
Colacurcio DJ, Nixon RA. Disorders of lysosomal acidification-The emerging role of v-ATPase in aging and neurodegenerative disease. Ageing Res Rev 2016; 32:75-88. [PMID: 27197071 DOI: 10.1016/j.arr.2016.05.004] [Citation(s) in RCA: 299] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/02/2016] [Accepted: 05/13/2016] [Indexed: 12/21/2022]
Abstract
Autophagy and endocytosis deliver unneeded cellular materials to lysosomes for degradation. Beyond processing cellular waste, lysosomes release metabolites and ions that serve signaling and nutrient sensing roles, linking the functions of the lysosome to various pathways for intracellular metabolism and nutrient homeostasis. Each of these lysosomal behaviors is influenced by the intraluminal pH of the lysosome, which is maintained in the low acidic range by a proton pump, the vacuolar ATPase (v-ATPase). New reports implicate altered v-ATPase activity and lysosomal pH dysregulation in cellular aging, longevity, and adult-onset neurodegenerative diseases, including forms of Parkinson disease and Alzheimer disease. Genetic defects of subunits composing the v-ATPase or v-ATPase-related proteins occur in an increasingly recognized group of familial neurodegenerative diseases. Here, we review the expanding roles of the v-ATPase complex as a platform regulating lysosomal hydrolysis and cellular homeostasis. We discuss the unique vulnerability of neurons to persistent low level lysosomal dysfunction and review recent clinical and experimental studies that link dysfunction of the v-ATPase complex to neurodegenerative diseases across the age spectrum.
Collapse
|
14
|
Boscardin E, Alijevic O, Hummler E, Frateschi S, Kellenberger S. The function and regulation of acid-sensing ion channels (ASICs) and the epithelial Na(+) channel (ENaC): IUPHAR Review 19. Br J Pharmacol 2016; 173:2671-701. [PMID: 27278329 DOI: 10.1111/bph.13533] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/19/2016] [Accepted: 06/02/2016] [Indexed: 12/30/2022] Open
Abstract
Acid-sensing ion channels (ASICs) and the epithelial Na(+) channel (ENaC) are both members of the ENaC/degenerin family of amiloride-sensitive Na(+) channels. ASICs act as proton sensors in the nervous system where they contribute, besides other roles, to fear behaviour, learning and pain sensation. ENaC mediates Na(+) reabsorption across epithelia of the distal kidney and colon and of the airways. ENaC is a clinically used drug target in the context of hypertension and cystic fibrosis, while ASIC is an interesting potential target. Following a brief introduction, here we will review selected aspects of ASIC and ENaC function. We discuss the origin and nature of pH changes in the brain and the involvement of ASICs in synaptic signalling. We expose how in the peripheral nervous system, ASICs cover together with other ion channels a wide pH range as proton sensors. We introduce the mechanisms of aldosterone-dependent ENaC regulation and the evidence for an aldosterone-independent control of ENaC activity, such as regulation by dietary K(+) . We then provide an overview of the regulation of ENaC by proteases, a topic of increasing interest over the past few years. In spite of the profound differences in the physiological and pathological roles of ASICs and ENaC, these channels share many basic functional and structural properties. It is likely that further research will identify physiological contexts in which ASICs and ENaC have similar or overlapping roles.
Collapse
Affiliation(s)
- Emilie Boscardin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Omar Alijevic
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | | | | |
Collapse
|
15
|
Lautemann J, Bohrmann J. Relating proton pumps with gap junctions: colocalization of ductin, the channel-forming subunit c of V-ATPase, with subunit a and with innexins 2 and 3 during Drosophila oogenesis. BMC DEVELOPMENTAL BIOLOGY 2016; 16:24. [PMID: 27412523 PMCID: PMC4944501 DOI: 10.1186/s12861-016-0124-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 06/29/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND Ion-transport mechanisms and gap junctions are known to cooperate in creating bioelectric phenomena, like pH gradients, voltage gradients and ion fluxes within single cells, tissues, organs, and whole organisms. Such phenomena have been shown to play regulatory roles in a variety of developmental and regenerative processes. Using Drosophila oogenesis as a model system, we aim at characterizing in detail the mechanisms underlying bioelectric phenomena in order to reveal their regulatory functions. We, therefore, investigated the stage-specific distribution patterns of V-ATPase components in relation to gap-junction proteins. RESULTS We analysed the localization of the V-ATPase components ductin (subunit c) and subunit a, and the gap-junction components innexins 2 and 3, especially in polar cells, border cells, stalk cells and centripetally migrating cells. These types of follicle cells had previously been shown to exhibit characteristic patterns of membrane channels as well as membrane potential and intracellular pH. Stage-specifically, ductin and subunit a were found either colocalized or separately enriched in different regions of soma and germ-line cells. While ductin was often more prominent in plasma membranes, subunit a was more prominent in cytoplasmic and nuclear vesicles. Particularly, ductin was enriched in polar cells, stalk cells, and nurse-cell membranes, whereas subunit a was enriched in the cytoplasm of border cells, columnar follicle cells and germ-line cells. Comparably, ductin and both innexins 2 and 3 were either colocalized or separately enriched in different cellular regions. While ductin often showed a continuous membrane distribution, the distribution of both innexins was mostly punctate. Particularly, ductin was enriched in polar cells and stalk cells, whereas innexin 2 was enriched in the oolemma, and innexin 3 in centripetally migrating follicle cells. In lateral follicle-cell membranes, the three proteins were found colocalized as well as separately concentrated in presumed gap-junction plaques. CONCLUSIONS Our results support the notion of a large variety of gap junctions existing in the Drosophila ovary. Moreover, since ductin is the channel-forming part of a proton pump and, like the innexins, is able to form junctional as well as non-junctional membrane channels, a plethora of cellular functions could be realized by using these proteins. The distribution and activity patterns of such membrane channels are expected to contribute to developmentally important bioelectric signals.
Collapse
Affiliation(s)
- Julia Lautemann
- Institut für Biologie II, RWTH Aachen University, Abt. Zoologie und Humanbiologie, Worringerweg 3, 52056, Aachen, Germany
| | - Johannes Bohrmann
- Institut für Biologie II, RWTH Aachen University, Abt. Zoologie und Humanbiologie, Worringerweg 3, 52056, Aachen, Germany.
| |
Collapse
|