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Sørensen DM, Bostock H, Abrahao A, Alaamel A, Alaydin HC, Ballegaard M, Boran E, Cengiz B, de Carvalho M, Dunker Ø, Fuglsang-Frederiksen A, Graffe CC, Jones KE, Kallio M, Kalra S, Krarup C, Krøigård T, Liguori R, Lupescu T, Maitland S, Matamala JM, Moldovan M, Moreno-Roco J, Nilsen KB, Phung L, Santos MO, Themistocleous AC, Uysal H, Vacchiano V, Whittaker RG, Zinman L, Tankisi H. Estimating motor unit numbers from a CMAP scan: Repeatability study on three muscles at 15 centres. Clin Neurophysiol 2023; 151:92-99. [PMID: 37236129 DOI: 10.1016/j.clinph.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/16/2023] [Accepted: 04/15/2023] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To assess the repeatability and suitability for multicentre studies of MScanFit motor unit number estimation (MUNE), which involves modelling compound muscle action potential (CMAP) scans. METHODS Fifteen groups in 9 countries recorded CMAP scans twice, 1-2 weeks apart in healthy subjects from abductor pollicis brevis (APB), abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. The original MScanFit program (MScanFit-1) was compared with a revised version (MScanFit-2), designed to accommodate different muscles and recording conditions by setting the minimal motor unit size as a function of maximum CMAP. RESULTS Complete sets of 6 recordings were obtained from 148 subjects. CMAP amplitudes differed significantly between centres for all muscles, and the same was true for MScanFit-1 MUNE. With MScanFit-2, MUNE differed less between centres but remained significantly different for APB. Coefficients of variation between repeats were 18.0% for ADM, 16.8% for APB, and 12.1% for TA. CONCLUSIONS It is recommended for multicentre studies to use MScanFit-2 for analysis. TA provided the least variable MUNE values between subjects and the most repeatable within subjects. SIGNIFICANCE MScanFit was primarily devised to model the discontinuities in CMAP scans in patients and is less suitable for healthy subjects with smooth scans.
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Affiliation(s)
- D M Sørensen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark
| | - H Bostock
- UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - A Abrahao
- Department of Medicine, University of Toronto, Toronto, Canada
| | - A Alaamel
- Department of Neurology, Akdeniz University Hospital, Antalya, Turkey
| | - H C Alaydin
- Department of Neurology, Gazi University, Ankara, Turkey
| | - M Ballegaard
- Department of Clinical Neurology, Zealand University Hospital, Roskilde, Denmark
| | - E Boran
- Department of Neurology, Gazi University, Ankara, Turkey
| | - B Cengiz
- Department of Neurology, Gazi University, Ankara, Turkey
| | - M de Carvalho
- Faculty of Medicine, iMM, Centro de Estudos Egas Moniz, Universidade de Lisboa, Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - Ø Dunker
- Department of Neurology and Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Norway
| | - A Fuglsang-Frederiksen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark; Department of Clinical Institute, Aarhus University, Aarhus, Denmark
| | - C C Graffe
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - K E Jones
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - M Kallio
- Department of Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - S Kalra
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - C Krarup
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - T Krøigård
- Department of Neurology, Odense University Hospital, Denmark
| | - R Liguori
- Dipertimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - T Lupescu
- Department of Neurology, Agrippa Ionescu Hospital, Bucharest, Romania
| | - S Maitland
- Translational and Clinical Research Institute, Newcastle University, United Kingdom
| | - J M Matamala
- Translational Neurology and Neurophysiology Lab, Department of Neurological Sciences and Biomedical Neuroscience Institute, University of Chile, Santiago, Chile
| | - M Moldovan
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - J Moreno-Roco
- Translational Neurology and Neurophysiology Lab, Department of Neurological Sciences and Biomedical Neuroscience Institute, University of Chile, Santiago, Chile
| | - K B Nilsen
- Department of Neurology and Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Norway
| | - L Phung
- Department of Medicine, University of Toronto, Toronto, Canada
| | - M O Santos
- Faculty of Medicine, iMM, Centro de Estudos Egas Moniz, Universidade de Lisboa, Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - A C Themistocleous
- Nuffield Department of Clinical Neurosciences University of Oxford, Oxford, United Kingdom
| | - H Uysal
- Department of Medicine, University of Toronto, Toronto, Canada
| | - V Vacchiano
- Dipertimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - R G Whittaker
- Translational and Clinical Research Institute, Newcastle University, United Kingdom
| | - L Zinman
- UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark; Department of Clinical Institute, Aarhus University, Aarhus, Denmark.
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Ipsen JØ, Sørensen DM. ATP hydrolytic activity of purified Spf1p correlate with micellar lipid fluidity and is dependent on conserved residues in transmembrane helix M1. PLoS One 2022; 17:e0274908. [PMID: 36264897 PMCID: PMC9584430 DOI: 10.1371/journal.pone.0274908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 09/06/2022] [Indexed: 11/29/2022] Open
Abstract
P5A ATPases are expressed in the endoplasmic reticulum (ER) of all eukaryotic cells, and their disruption results in pleiotropic phenotypes related to severe ER stress. They were recently proposed to function in peptide translocation although their specificity have yet to be confirmed in reconstituted assays using the purified enzyme. A general theme for P-type ATPases is that binding and transport of substrates is coupled to hydrolysis of ATP in a conserved allosteric mechanism, however several independent reports have shown purified Spf1p to display intrinsic spontaneous ATP hydrolytic activity after purification. It has never been determined to what extend this spontaneous activity is caused by uncoupling of the enzyme. In this work we have purified a functional tagged version of the Saccharomyces cerevisiae P5A ATPase Spf1p and have observed that the intrinsic ATP hydrolytic activity of the purified and re-lipidated protein can be stimulated by specific detergents (C12E8, C12E10 and Tween20) in mixed lipid/detergent micelles in the absence of any apparent substrate. We further show that this increase in activity correlate with the reaction temperature and the anisotropic state of the mixed lipid/detergent micelles and further that this correlation relies on three highly conserved phenylalanine residues in M1. This suggests that at least part of the intrinsic ATP hydrolytic activity is allosterically coupled to movements in the TM domain in the purified preparations. It is suggested that free movement of the M1 helix represent an energetic constraint on catalysis and that this constraint likely is lost in the purified preparations resulting in protein with intrinsic spontaneous ATP hydrolytic activity. Removal of the N-terminal part of the protein apparently removes this activity.
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Affiliation(s)
- Johan Ørskov Ipsen
- Center for Membrane Pumps in Cells and Disease—PUMPKIN, Danish National Research Foundation, Copenhagen, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- Department of Geoscience and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Danny Mollerup Sørensen
- Center for Membrane Pumps in Cells and Disease—PUMPKIN, Danish National Research Foundation, Copenhagen, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- * E-mail:
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Palmgren M, Sørensen DM, Hallström BM, Säll T, Broberg K. Evolution of P2A and P5A ATPases: ancient gene duplications and the red algal connection to green plants revisited. Physiol Plant 2020; 168:630-647. [PMID: 31268560 PMCID: PMC7065118 DOI: 10.1111/ppl.13008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/20/2019] [Accepted: 06/27/2019] [Indexed: 05/14/2023]
Abstract
In a search for slowly evolving nuclear genes that may cast light on the deep evolution of plants, we carried out phylogenetic analyses of two well-characterized subfamilies of P-type pumps (P2A and P5A ATPases) from representative branches of the eukaryotic tree of life. Both P-type ATPase genes were duplicated very early in eukaryotic evolution and before the divergence of the present eukaryotic supergroups. Synapomorphies identified in the sequences provide evidence that green plants and red algae are more distantly related than are green plants and eukaryotic supergroups in which secondary or tertiary plastids are common, such as several groups belonging to the clade that includes Stramenopiles, Alveolata, Rhizaria, Cryptophyta and Haptophyta (SAR). We propose that red algae branched off soon after the first photosynthesizing eukaryote had acquired a primary plastid, while in another lineage that led to SAR, the primary plastid was lost but, in some cases, regained as a secondary or tertiary plastid.
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Affiliation(s)
- Michael Palmgren
- Department of Plant and Environmental SciencesUniversity of CopenhagenCopenhagenDenmark
- Institute of Environmental MedicineKarolinska InstitutetStockholmSweden
| | | | - Björn M. Hallström
- Science for Life LaboratoryKTH – Royal Institute of TechnologyStockholmSweden
| | | | - Karin Broberg
- Institute of Environmental MedicineKarolinska InstitutetStockholmSweden
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Sørensen DM, Holen HW, Pedersen JT, Martens HJ, Silvestro D, Stanchev LD, Costa SR, Günther Pomorski T, López-Marqués RL, Palmgren M. The P5A ATPase Spf1p is stimulated by phosphatidylinositol 4-phosphate and influences cellular sterol homeostasis. Mol Biol Cell 2019; 30:1069-1084. [PMID: 30785834 PMCID: PMC6724510 DOI: 10.1091/mbc.e18-06-0365] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
P5A ATPases are expressed in the endoplasmic reticulum (ER) of all eukaryotic cells, and their disruption results in severe ER stress. However, the function of these ubiquitous membrane proteins, which belong to the P-type ATPase superfamily, is unknown. We purified a functional tagged version of the Saccharomyces cerevisiae P5A ATPase Spf1p and observed that the ATP hydrolytic activity of the protein is stimulated by phosphatidylinositol 4-phosphate (PI4P). Furthermore, SPF1 exhibited negative genetic interactions with SAC1, encoding a PI4P phosphatase, and with OSH1 to OSH6, encoding Osh proteins, which, when energized by a PI4P gradient, drive export of sterols and lipids from the ER. Deletion of SPF1 resulted in increased sensitivity to inhibitors of sterol production, a marked change in the ergosterol/lanosterol ratio, accumulation of sterols in the plasma membrane, and cytosolic accumulation of lipid bodies. We propose that Spf1p maintains cellular sterol homeostasis by influencing the PI4P-induced and Osh-mediated export of sterols from the ER.
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Affiliation(s)
- Danny Mollerup Sørensen
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Henrik Waldal Holen
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Jesper Torbøl Pedersen
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Helle Juel Martens
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Daniele Silvestro
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Lyubomir Dimitrov Stanchev
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Sara Rute Costa
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Thomas Günther Pomorski
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Rosa Laura López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
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Sørensen DM, Holemans T, van Veen S, Martin S, Arslan T, Haagendahl IW, Holen HW, Hamouda NN, Eggermont J, Palmgren M, Vangheluwe P. Parkinson disease related ATP13A2 evolved early in animal evolution. PLoS One 2018; 13:e0193228. [PMID: 29505581 PMCID: PMC5837089 DOI: 10.1371/journal.pone.0193228] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 02/07/2018] [Indexed: 12/30/2022] Open
Abstract
Several human P5-type transport ATPases are implicated in neurological disorders, but little is known about their physiological function and properties. Here, we investigated the relationship between the five mammalian P5 isoforms ATP13A1-5 in a comparative study. We demonstrated that ATP13A1-4 isoforms undergo autophosphorylation, which is a hallmark P-type ATPase property that is required for substrate transport. A phylogenetic analysis of P5 sequences revealed that ATP13A1 represents clade P5A, which is highly conserved between fungi and animals with one member in each investigated species. The ATP13A2-5 isoforms belong to clade P5B and diversified from one isoform in fungi and primitive animals to a maximum of four in mammals by successive gene duplication events in vertebrate evolution. We revealed that ATP13A1 localizes in the endoplasmic reticulum (ER) and experimentally demonstrate that ATP13A1 likely contains 12 transmembrane helices. Conversely, ATP13A2-5 isoforms reside in overlapping compartments of the endosomal system and likely contain 10 transmembrane helices, similar to what was demonstrated earlier for ATP13A2. ATP13A1 complemented a deletion of the yeast P5A ATPase SPF1, while none of ATP13A2-5 could complement either the loss of SPF1 or that of the single P5B ATPase YPK9 in yeast. Thus, ATP13A1 carries out a basic ER function similar to its yeast counterpart Spf1p that plays a role in ER related processes like protein folding and processing. ATP13A2-5 isoforms diversified in mammals and are expressed in the endosomal system where they may have evolved novel complementary or partially redundant functions. While most P5-type ATPases are widely expressed, some P5B-type ATPases (ATP13A4 and ATP13A5) display a more limited tissue distribution in the brain and epithelial glandular cells, where they may exert specialized functions. At least some P5B isoforms are of vital importance for the nervous system, since ATP13A2 and ATP13A4 are linked to respectively Parkinson disease and autism spectrum disorders.
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Affiliation(s)
- Danny Mollerup Sørensen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Tine Holemans
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
| | - Sarah van Veen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
| | - Shaun Martin
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
| | - Tugce Arslan
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
| | - Ida Winther Haagendahl
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Henrik Waldal Holen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Norin Nabil Hamouda
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
| | - Jan Eggermont
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
| | - Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; Leuven, Belgium
- * E-mail:
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Estrada-Cuzcano A, Martin S, Chamova T, Synofzik M, Timmann D, Holemans T, Andreeva A, Reichbauer J, De Rycke R, Chang DI, van Veen S, Samuel J, Schöls L, Pöppel T, Mollerup Sørensen D, Asselbergh B, Klein C, Zuchner S, Jordanova A, Vangheluwe P, Tournev I, Schüle R. Loss-of-function mutations in the ATP13A2/PARK9 gene cause complicated hereditary spastic paraplegia (SPG78). Brain 2017; 140:287-305. [PMID: 28137957 DOI: 10.1093/brain/aww307] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/29/2016] [Accepted: 10/19/2016] [Indexed: 12/23/2022] Open
Abstract
Hereditary spastic paraplegias are heterogeneous neurodegenerative disorders characterized by progressive spasticity of the lower limbs due to degeneration of the corticospinal motor neurons. In a Bulgarian family with three siblings affected by complicated hereditary spastic paraplegia, we performed whole exome sequencing and homozygosity mapping and identified a homozygous p.Thr512Ile (c.1535C > T) mutation in ATP13A2. Molecular defects in this gene have been causally associated with Kufor-Rakeb syndrome (#606693), an autosomal recessive form of juvenile-onset parkinsonism, and neuronal ceroid lipofuscinosis (#606693), a neurodegenerative disorder characterized by the intracellular accumulation of autofluorescent lipopigments. Further analysis of 795 index cases with hereditary spastic paraplegia and related disorders revealed two additional families carrying truncating biallelic mutations in ATP13A2. ATP13A2 is a lysosomal P5-type transport ATPase, the activity of which critically depends on catalytic autophosphorylation. Our biochemical and immunocytochemical experiments in COS-1 and HeLa cells and patient-derived fibroblasts demonstrated that the hereditary spastic paraplegia-associated mutations, similarly to the ones causing Kufor-Rakeb syndrome and neuronal ceroid lipofuscinosis, cause loss of ATP13A2 function due to transcript or protein instability and abnormal intracellular localization of the mutant proteins, ultimately impairing the lysosomal and mitochondrial function. Moreover, we provide the first biochemical evidence that disease-causing mutations can affect the catalytic autophosphorylation activity of ATP13A2. Our study adds complicated hereditary spastic paraplegia (SPG78) to the clinical continuum of ATP13A2-associated neurological disorders, which are commonly hallmarked by lysosomal and mitochondrial dysfunction. The disease presentation in our patients with hereditary spastic paraplegia was dominated by an adult-onset lower-limb predominant spastic paraparesis. Cognitive impairment was present in most of the cases and ranged from very mild deficits to advanced dementia with fronto-temporal characteristics. Nerve conduction studies revealed involvement of the peripheral motor and sensory nerves. Only one of five patients with hereditary spastic paraplegia showed clinical indication of extrapyramidal involvement in the form of subtle bradykinesia and slight resting tremor. Neuroimaging cranial investigations revealed pronounced vermian and hemispheric cerebellar atrophy. Notably, reduced striatal dopamine was apparent in the brain of one of the patients, who had no clinical signs or symptoms of extrapyramidal involvement.
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Affiliation(s)
- Alejandro Estrada-Cuzcano
- Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Shaun Martin
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; 3000 Leuven, Belgium
| | - Teodora Chamova
- Department of Neurology, Medical University-Sofia, 1431 Sofia, Bulgaria
| | - Matthis Synofzik
- Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Dagmar Timmann
- Department of Neurology, Essen University Hospital, University of Duisburg-Essen, 45147 Essen, Germany
| | - Tine Holemans
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; 3000 Leuven, Belgium
| | - Albena Andreeva
- Department of Neurology, Medical University-Sofia, 1431 Sofia, Bulgaria
| | - Jennifer Reichbauer
- Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Riet De Rycke
- Inflammation Research Center, VIB, Ghent, Belgium and Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Dae-In Chang
- Inflammation Research Center, VIB, Ghent, Belgium and Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Sarah van Veen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; 3000 Leuven, Belgium
| | - Jean Samuel
- Department of Neurology, Medical University-Sofia, 1431 Sofia, Bulgaria
| | - Ludger Schöls
- Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Thorsten Pöppel
- Department of Nuclear Medicine, Essen University Hospital, University of Duisburg-Essen, 45147 Essen, Germany
| | - Danny Mollerup Sørensen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; 3000 Leuven, Belgium
| | - Bob Asselbergh
- VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Christine Klein
- Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium.,Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Stephan Zuchner
- Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Albena Jordanova
- Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium.,Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium.,Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; 3000 Leuven, Belgium
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven; 3000 Leuven, Belgium
| | - Ivailo Tournev
- Department of Neurology, Medical University-Sofia, 1431 Sofia, Bulgaria.,Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium.,Department of Neurology, Medical University-Sofia, 1431 Sofia, Bulgaria
| | - Rebecca Schüle
- Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany .,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany.,Molecular Neurogenomics Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
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Sørensen DM, Holen HW, Holemans T, Vangheluwe P, Palmgren MG. Towards defining the substrate of orphan P5A-ATPases. Biochim Biophys Acta Gen Subj 2014; 1850:524-35. [PMID: 24836520 DOI: 10.1016/j.bbagen.2014.05.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND P-type ATPases are ubiquitous ion and lipid pumps found in cellular membranes. P5A-ATPases constitute a poorly characterized subfamily of P-type ATPases present in all eukaryotic organisms but for which a transported substrate remains to be identified. SCOPE OF REVIEW This review aims to discuss the available evidence which could lead to identification of possible substrates of P5A-ATPases. MAJOR CONCLUSIONS The complex phenotypes resulting from the loss of P5A-ATPases in model organisms can be explained by a role of the P5A-ATPase in the endoplasmic reticulum (ER), where loss of function leads to broad and unspecific phenotypes related to the impairment of basic ER functions such as protein folding and processing. Genetic interactions in Saccharomyces cerevisiae point to a role of the endogenous P5A-ATPase Spf1p in separation of charges in the ER, in sterol metabolism, and in insertion of tail-anchored proteins in the ER membrane. A role for P5A-ATPases in vesicle formation would explain why sterol transport and distribution are affected in knock out cells, which in turn has a negative impact on the spontaneous insertion of tail-anchored proteins. It would also explain why secretory proteins destined for the Golgi and the cell wall have difficulties in reaching their final destination. Cations and phospholipids could both be transported substrates of P5A-ATPases and as each carry charges, transport of either might explain why a charge difference arises across the ER membrane. GENERAL SIGNIFICANCE Identification of the substrate of P5A-ATPases would throw light on an important general process in the ER that is still not fully understood. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.
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Affiliation(s)
- Danny Mollerup Sørensen
- Centre for Membrane Pumps in Cells and Disease-PUMPkin, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Henrik Waldal Holen
- Centre for Membrane Pumps in Cells and Disease-PUMPkin, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Tine Holemans
- Department of Cellular and Molecular Medicine, ON1 Campus Gasthuisberg, Katholieke Universiteit Leuven, Herestraat 49, Box 802, B3000 Leuven, Belgium
| | - Peter Vangheluwe
- Department of Cellular and Molecular Medicine, ON1 Campus Gasthuisberg, Katholieke Universiteit Leuven, Herestraat 49, Box 802, B3000 Leuven, Belgium
| | - Michael G Palmgren
- Centre for Membrane Pumps in Cells and Disease-PUMPkin, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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Sørensen DM, Møller AB, Jakobsen MK, Jensen MK, Vangheluwe P, Buch-Pedersen MJ, Palmgren MG. Ca2+ induces spontaneous dephosphorylation of a novel P5A-type ATPase. J Biol Chem 2012; 287:28336-48. [PMID: 22730321 DOI: 10.1074/jbc.m112.387191] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
P5 ATPases constitute the least studied group of P-type ATPases, an essential family of ion pumps in all kingdoms of life. Although P5 ATPases are present in every eukaryotic genome analyzed so far, they have remained orphan pumps, and their biochemical function is obscure. We show that a P5A ATPase from barley, HvP5A1, locates to the endoplasmic reticulum and is able to rescue knock-out mutants of P5A genes in both Arabidopsis thaliana and Saccharomyces cerevisiae. HvP5A1 spontaneously forms a phosphorylated reaction cycle intermediate at the catalytic residue Asp-488, whereas, among all plant nutrients tested, only Ca(2+) triggers dephosphorylation. Remarkably, Ca(2+)-induced dephosphorylation occurs at high apparent [Ca(2+)] (K(i) = 0.25 mM) and is independent of the phosphatase motif of the pump and the putative binding site for transported ligands located in M4. Taken together, our results rule out that Ca(2+) is a transported substrate but indicate the presence of a cytosolic low affinity Ca(2+)-binding site, which is conserved among P-type pumps and could be involved in pump regulation. Our work constitutes the first characterization of a P5 ATPase phosphoenzyme and points to Ca(2+) as a modifier of its function.
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Affiliation(s)
- Danny Mollerup Sørensen
- Centre for Membrane Pumps in Cells and Disease, PUMPKIN, Danish National Research Foundation, Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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Sørensen DM, Buch-Pedersen MJ, Palmgren MG. Structural divergence between the two subgroups of P5 ATPases. Biochim Biophys Acta 2010; 1797:846-55. [PMID: 20416272 DOI: 10.1016/j.bbabio.2010.04.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 04/09/2010] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
Abstract
Evolution of P5 type ATPases marks the origin of eukaryotes but still they remain the least characterized pumps in the superfamily of P-type ATPases. Phylogenetic analysis of available sequences suggests that P5 ATPases should be divided into at least two subgroups, P5A and P5B. P5A ATPases have been identified in the endoplasmic reticulum and seem to have basic functions in protein maturation and secretion. P5B ATPases localize to vacuolar/lysosomal or apical membranes and in animals play a role in hereditary neuronal diseases. Here we have used a bioinformatical approach to identify differences in the primary sequences between the two subgroups. P5A and P5B ATPases appear have a very different membrane topology from other P-type ATPases with two and one, respectively, additional transmembrane segments inserted in the N-terminal end. Based on conservation of residues in the transmembrane region, the two P5 subgroups most likely have different substrate specificities although these cannot be predicted from their sequences. Furthermore, sequence differences between P5A and P5B ATPases are identified in the catalytic domains that could influence key kinetic properties differentially. Together these findings indicate that P5A and P5B ATPases are structurally and functionally different.
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Affiliation(s)
- Danny Mollerup Sørensen
- Centre for Membrane Pumps in Cells and Disease, PUMPKIN, Danish National Research Foundation, Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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