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Banjac K, Obradovic M, Zafirovic S, Essack M, Gluvic Z, Sunderic M, Nedic O, Isenovic ER. The involvement of Akt, mTOR, and S6K in the in vivo effect of IGF-1 on the regulation of rat cardiac Na +/K +-ATPase. Mol Biol Rep 2024; 51:517. [PMID: 38622478 DOI: 10.1007/s11033-024-09451-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/15/2024] [Indexed: 04/17/2024]
Abstract
BACKGROUND We previously demonstrated that insulin-like growth factor-1 (IGF-1) regulates sodium/potassium adenosine triphosphatase (Na+/K+-ATPase) in vascular smooth muscle cells (VSMC) via phosphatidylinositol-3 kinase (PI3K). Taking into account that others' work show that IGF-1 activates the PI3K/protein kinase B (Akt) signaling pathway in many different cells, we here further questioned if the Akt/mammalian target of rapamycin (mTOR)/ribosomal protein p70 S6 kinase (S6K) pathway stimulates Na+/K+-ATPase, an essential protein for maintaining normal heart function. METHODS AND RESULTS There were 14 adult male Wistar rats, half of whom received bolus injections of IGF-1 (50 μg/kg) for 24 h. We evaluated cardiac Na+/K+-ATPase expression, activity, and serum IGF-1 levels. Additionally, we examined the phosphorylated forms of the following proteins: insulin receptor substrate (IRS), phosphoinositide-dependent kinase-1 (PDK-1), Akt, mTOR, S6K, and α subunit of Na+/K+-ATPase. Additionally, the mRNA expression of the Na+/K+-ATPase α1 subunit was evaluated. Treatment with IGF-1 increases levels of serum IGF-1 and stimulates Na+/K+-ATPase activity, phosphorylation of α subunit of Na+/K+-ATPase on Ser23, and protein expression of α2 subunit. Furthermore, IGF-1 treatment increased phosphorylation of IRS-1 on Tyr1222, Akt on Ser473, PDK-1 on Ser241, mTOR on Ser2481 and Ser2448, and S6K on Thr421/Ser424. The concentration of IGF-1 in serum positively correlates with Na+/K+-ATPase activity and the phosphorylated form of mTOR (Ser2448), while Na+/K+-ATPase activity positively correlates with the phosphorylated form of IRS-1 (Tyr1222) and mTOR (Ser2448). CONCLUSION These results indicate that the Akt/mTOR/S6K signalling pathway may be involved in the IGF-1 regulating cardiac Na+/K+-ATPase expression and activity.
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Affiliation(s)
- Katarina Banjac
- Department of Radiobiology and Molecular Genetics, "VINCA" Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, P.O.Box 522, Belgrade, 11000, Serbia
| | - Milan Obradovic
- Department of Radiobiology and Molecular Genetics, "VINCA" Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, P.O.Box 522, Belgrade, 11000, Serbia.
| | - Sonja Zafirovic
- Department of Radiobiology and Molecular Genetics, "VINCA" Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, P.O.Box 522, Belgrade, 11000, Serbia
| | - Magbubah Essack
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Zoran Gluvic
- Clinic of Internal Medicine, School of Medicine, University Clinical-Hospital Centre Zemun-Belgrade, University of Belgrade, Vukova 9, Belgrade, 11080, Serbia
| | - Milos Sunderic
- Institute for the Application of Nuclear Energy, Department for Metabolism, University of Belgrade, Banatska 31b, Belgrade, Serbia
| | - Olgica Nedic
- Institute for the Application of Nuclear Energy, Department for Metabolism, University of Belgrade, Banatska 31b, Belgrade, Serbia
| | - Esma R Isenovic
- Department of Radiobiology and Molecular Genetics, "VINCA" Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, P.O.Box 522, Belgrade, 11000, Serbia
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2
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Blaustein MP, Hamlyn JM. Sensational site: the sodium pump ouabain-binding site and its ligands. Am J Physiol Cell Physiol 2024; 326:C1120-C1177. [PMID: 38223926 DOI: 10.1152/ajpcell.00273.2023] [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: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
Cardiotonic steroids (CTS), used by certain insects, toads, and rats for protection from predators, became, thanks to Withering's trailblazing 1785 monograph, the mainstay of heart failure (HF) therapy. In the 1950s and 1960s, we learned that the CTS receptor was part of the sodium pump (NKA) and that the Na+/Ca2+ exchanger was critical for the acute cardiotonic effect of digoxin- and ouabain-related CTS. This "settled" view was upended by seven revolutionary observations. First, subnanomolar ouabain sometimes stimulates NKA while higher concentrations are invariably inhibitory. Second, endogenous ouabain (EO) was discovered in the human circulation. Third, in the DIG clinical trial, digoxin only marginally improved outcomes in patients with HF. Fourth, cloning of NKA in 1985 revealed multiple NKA α and β subunit isoforms that, in the rodent, differ in their sensitivities to CTS. Fifth, the NKA is a cation pump and a hormone receptor/signal transducer. EO binding to NKA activates, in a ligand- and cell-specific manner, several protein kinase and Ca2+-dependent signaling cascades that have widespread physiological effects and can contribute to hypertension and HF pathogenesis. Sixth, all CTS are not equivalent, e.g., ouabain induces hypertension in rodents while digoxin is antihypertensinogenic ("biased signaling"). Seventh, most common rodent hypertension models require a highly ouabain-sensitive α2 NKA and the elevated blood pressure is alleviated by EO immunoneutralization. These numerous phenomena are enabled by NKA's intricate structure. We have just begun to understand the endocrine role of the endogenous ligands and the broad impact of the ouabain-binding site on physiology and pathophysiology.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
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3
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Aßfalg M, Güner G, Müller SA, Breimann S, Langosch D, Muhle-Goll C, Frishman D, Steiner H, Lichtenthaler SF. Cleavage efficiency of the intramembrane protease γ-secretase is reduced by the palmitoylation of a substrate's transmembrane domain. FASEB J 2024; 38:e23442. [PMID: 38275103 DOI: 10.1096/fj.202302152r] [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: 10/26/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 01/27/2024]
Abstract
The intramembrane protease γ-secretase has broad physiological functions, but also contributes to Notch-dependent tumors and Alzheimer's disease. While γ-secretase cleaves numerous membrane proteins, only few nonsubstrates are known. Thus, a fundamental open question is how γ-secretase distinguishes substrates from nonsubstrates and whether sequence-based features or post-translational modifications of membrane proteins contribute to substrate recognition. Using mass spectrometry-based proteomics, we identified several type I membrane proteins with short ectodomains that were inefficiently or not cleaved by γ-secretase, including 'pituitary tumor-transforming gene 1-interacting protein' (PTTG1IP). To analyze the mechanism preventing cleavage of these putative nonsubstrates, we used the validated substrate FN14 as a backbone and replaced its transmembrane domain (TMD), where γ-cleavage occurs, with the one of nonsubstrates. Surprisingly, some nonsubstrate TMDs were efficiently cleaved in the FN14 backbone, demonstrating that a cleavable TMD is necessary, but not sufficient for cleavage by γ-secretase. Cleavage efficiencies varied by up to 200-fold. Other TMDs, including that of PTTG1IP, were still barely cleaved within the FN14 backbone. Pharmacological and mutational experiments revealed that the PTTG1IP TMD is palmitoylated, which prevented cleavage by γ-secretase. We conclude that the TMD sequence of a membrane protein and its palmitoylation can be key factors determining substrate recognition and cleavage efficiency by γ-secretase.
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Affiliation(s)
- Marlene Aßfalg
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Gökhan Güner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Stephan A Müller
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Stephan Breimann
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Bioinformatics, School of Life Sciences, Technical University of Munich, Freising, Germany
- Biomedical Center (BMC), Division of Metabolic Biochemistry, Faculty of Medicine, LMU Munich, Munich, Germany
| | | | - Claudia Muhle-Goll
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Dmitrij Frishman
- Department of Bioinformatics, School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Harald Steiner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Biomedical Center (BMC), Division of Metabolic Biochemistry, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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4
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Spontarelli K, Young VC, Sweazey R, Padro A, Lee J, Bueso T, Hernandez RM, Kim J, Katz A, Rossignol F, Turner C, Wilczewski CM, Maxwell GL, Holmgren M, Bailoo JD, Yano ST, Artigas P. ATP1A1-linked diseases require a malfunctioning protein product from one allele. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119572. [PMID: 37659504 DOI: 10.1016/j.bbamcr.2023.119572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/06/2023] [Accepted: 08/22/2023] [Indexed: 09/04/2023]
Abstract
Heterozygous germline variants in ATP1A1, the gene encoding the α1 subunit of the Na+/K+-ATPase (NKA), have been linked to diseases including primary hyperaldosteronism and the peripheral neuropathy Charcot-Marie-Tooth disease (CMT). ATP1A1 variants that cause CMT induce loss-of-function of NKA. This heterodimeric (αβ) enzyme hydrolyzes ATP to establish transmembrane electrochemical gradients of Na+ and K+ that are essential for electrical signaling and cell survival. Of the 4 catalytic subunit isoforms, α1 is ubiquitously expressed and is the predominant paralog in peripheral axons. Human population sequencing datasets indicate strong negative selection against both missense and protein-null ATP1A1 variants. To test whether haploinsufficiency generated by heterozygous protein-null alleles are sufficient to cause disease, we tested the neuromuscular characteristics of heterozygous Atp1a1+/- knockout mice and their wildtype littermates, while also evaluating if exercise increased CMT penetrance. We found that Atp1a1+/- mice were phenotypically normal up to 18 months of age. Consistent with the observations in mice, we report clinical phenotyping of a healthy adult human who lacks any clinical features of known ATP1A1-related diseases despite carrying a plasma-membrane protein-null early truncation variant, p.Y148*. Taken together, these results suggest that a malfunctioning gene product is required for disease induction by ATP1A1 variants and that if any pathology is associated with protein-null variants, they may display low penetrance or high age of onset.
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Affiliation(s)
- Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Victoria C Young
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Ryan Sweazey
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Alexandria Padro
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Jeannie Lee
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Tulio Bueso
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Roberto M Hernandez
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Jongyeol Kim
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Alexander Katz
- NIH Reverse Phenotyping Core, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Francis Rossignol
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Clesson Turner
- NIH Reverse Phenotyping Core, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Caralynn M Wilczewski
- NIH Reverse Phenotyping Core, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - George L Maxwell
- Women's Health Integrated Research Center, Inova Health System, Falls Church, VA, USA
| | - Miguel Holmgren
- Molecular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Jeremy D Bailoo
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Sho T Yano
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA; Molecular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA; Current address: Section of Pediatric Neurology, Department of Pediatrics, University of Chicago, Chicago, IL, USA.
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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5
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Artigas P, Meyer DJ, Young VC, Spontarelli K, Eastman J, Strandquist E, Rui H, Roux B, Birk MA, Nakanishi H, Abe K, Gatto C. A Na pump with reduced stoichiometry is up-regulated by brine shrimp in extreme salinities. Proc Natl Acad Sci U S A 2023; 120:e2313999120. [PMID: 38079564 PMCID: PMC10756188 DOI: 10.1073/pnas.2313999120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023] Open
Abstract
Brine shrimp (Artemia) are the only animals to thrive at sodium concentrations above 4 M. Salt excretion is powered by the Na+,K+-ATPase (NKA), a heterodimeric (αβ) pump that usually exports 3Na+ in exchange for 2 K+ per hydrolyzed ATP. Artemia express several NKA catalytic α-subunit subtypes. High-salinity adaptation increases abundance of α2KK, an isoform that contains two lysines (Lys308 and Lys758 in transmembrane segments TM4 and TM5, respectively) at positions where canonical NKAs have asparagines (Xenopus α1's Asn333 and Asn785). Using de novo transcriptome assembly and qPCR, we found that Artemia express two salinity-independent canonical α subunits (α1NN and α3NN), as well as two β variants, in addition to the salinity-controlled α2KK. These β subunits permitted heterologous expression of the α2KK pump and determination of its CryoEM structure in a closed, ion-free conformation, showing Lys758 residing within the ion-binding cavity. We used electrophysiology to characterize the function of α2KK pumps and compared it to that of Xenopus α1 (and its α2KK-mimicking single- and double-lysine substitutions). The double substitution N333K/N785K confers α2KK-like characteristics to Xenopus α1, and mutant cycle analysis reveals energetic coupling between these two residues, illustrating how α2KK's Lys308 helps to maintain high affinity for external K+ when Lys758 occupies an ion-binding site. By measuring uptake under voltage clamp of the K+-congener 86Rb+, we prove that double-lysine-substituted pumps transport 2Na+ and 1 K+ per catalytic cycle. Our results show how the two lysines contribute to generate a pump with reduced stoichiometry allowing Artemia to maintain steeper Na+ gradients in hypersaline environments.
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Affiliation(s)
- Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Dylan J. Meyer
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Victoria C. Young
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Jessica Eastman
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Evan Strandquist
- School of Biological Sciences, Illinois State University, Normal, IL61790
| | - Huan Rui
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL60637
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL60637
| | - Matthew A. Birk
- Department of Biology, Saint Francis University, Loretto, PA15940
| | - Hanayo Nakanishi
- Department of Basic Medical Sciences, Cellular and Structural Physiology Institute, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya464-8601, Japan
| | - Kazuhiro Abe
- Department of Basic Medical Sciences, Cellular and Structural Physiology Institute, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya464-8601, Japan
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL61790
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Bobotis BC, Braniff O, Gargus M, Akinluyi ET, Awogbindin IO, Tremblay MÈ. Sex differences of microglia in the healthy brain from embryonic development to adulthood and across lifestyle influences. Brain Res Bull 2023; 202:110752. [PMID: 37652267 DOI: 10.1016/j.brainresbull.2023.110752] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/15/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023]
Abstract
Microglia, the central nervous system innate immune cells, play a critical role in maintaining a homeostatic environment in the brain throughout life. These cells exhibit an impressive range of functions and characteristics that help to ensure proper functioning of the brain. Notably, microglia can present differences in their genetic and physical traits, which can be influenced by a range of factors, including age, environmental exposures, disease, and sex. Remarkably, microglia have been found to express receptors for sex hormones, suggesting that these hormones may play a role in modulating microglial behavior and potentially contribute to sex differences. Additionally, sex-chromosomal factors were shown to impact microglial genetics and functioning. In this review, we will examine how microglial responses in homeostasis are impacted by their interaction with sex hormones and sex chromosomes. Specifically, our investigation will focus on examining this interaction from embryonic development to adulthood, and the influence of lifestyle elements on various microglial features, including density and distribution, morphology, transcriptome, and proteome.
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Affiliation(s)
| | - Olivia Braniff
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Makenna Gargus
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Elizabeth Toyin Akinluyi
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Department of Pharmacology and Therapeutics, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Ifeoluwa Oluleke Awogbindin
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Neuroimmunology Group, Molecular Drug Metabolism and Toxicology Laboratory, Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Neurosciences Axis, Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada; Department of Molecular Medicine, Université Laval, Québec, QC, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.
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7
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Palmgren M. Evolution of the sodium pump. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119511. [PMID: 37301269 DOI: 10.1016/j.bbamcr.2023.119511] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/16/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023]
Abstract
Eukaryotic plasma membranes (PMs) are energized by electrogenic P-type ATPases that generate either Na+ or H+ motive forces to drive Na+ and H+ dependent transport processes, respectively. For this purpose, animal rely on Na+/K+-ATPases whereas fungi and plants employ PM H+-ATPases. Prokaryotes, on the other hand, depend on H+ or Na+-motive electron transport complexes to energize their cell membranes. This raises the question as to why and when electrogenic Na+ and H+ pumps evolved? Here it is shown that prokaryotic Na+/K+-ATPases have near perfect conservation of binding sites involved in coordination of three Na+ and two K+ ions. Such pumps are rare in Eubacteria but are common in methanogenic Archaea where they often are found together with P-type putative PM H+-ATPases. With some exceptions, Na+/K+-ATPases and PM H+-ATPases are found everywhere in the eukaryotic tree of life, but never together in animals, fungi and land plants. It is hypothesized that Na+/K+-ATPases and PM H+-ATPases evolved in methanogenic Archaea to support the bioenergetics of these ancestral organisms, which can utilize both H+ and Na+ as energy currencies. Both pumps must have been simultaneously present in the first eukaryotic cell, but during diversification of the major eukaryotic kingdoms, and at the time animals diverged from fungi, animals kept Na+/K+-ATPases but lost PM H+-ATPases. At the same evolutionary branch point, fungi did loose Na+/K+-ATPases, and their role was taken over by PM H+-ATPases. An independent but similar scenery emerged during terrestrialization of plants: they lost Na+/K+-ATPases but kept PM H+-ATPases.
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Affiliation(s)
- Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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8
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Liu X, Wang M, Qin J, Liu Y, Chai Z, Peng W, Kangzhu Y, Zhong J, Wang J. Identification of Candidate Genes Associated with Yak Body Size Using a Genome-Wide Association Study and Multiple Populations of Information. Animals (Basel) 2023; 13:ani13091470. [PMID: 37174506 PMCID: PMC10177615 DOI: 10.3390/ani13091470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/23/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
Yaks have evolved several breeds or genetic resources owing to their geographical and ecological environment, and investigating the genetic construction of body size among breeds is key for breeding. Here, a genome-wide association study (GWAS) was performed for five body size traits in 31 yak breeds and genetic resources. The information from clustering individuals according to their habitats was used for kinship grouping in the compressed mixed linear model (CMLM). We named this approach the pCMLM method. A total of 3,584,464 high-quality single nucleotide polymorphisms (SNPs) were obtained, and six markers were found to be significantly associated with height by pCMLM. Four candidate genes, including FXYD6, SOHLH2, ADGRB2, and OSBPL6, were identified. Our results show that when CMLM cannot identify optimal clustering groups, pCMLM can provide sufficient associated results based on population information. Moreover, this study provides basic information on the gene localization of quantitative traits of body size among yak breeds.
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Affiliation(s)
- Xinrui Liu
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Mingxiu Wang
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Jie Qin
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Yaxin Liu
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Zhixin Chai
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Wei Peng
- Qinghai Academy of Animal Science and Veterinary Science, Qinghai University, Xining 810016, China
| | - Yixi Kangzhu
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Jincheng Zhong
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Jiabo Wang
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
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9
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Spontarelli K, Young VC, Sweazey R, Padro A, Lee J, Bueso T, Hernandez RM, Kim J, Katz A, Rossignol F, Turner C, Wilczewski CM, Maxwell GL, Holmgren M, Bailoo JD, Yano ST, Artigas P. ATP1A1 -linked diseases require a malfunctioning protein product from one allele. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.05.531165. [PMID: 37090550 PMCID: PMC10120656 DOI: 10.1101/2023.03.05.531165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Heterozygous germline variants in ATP1A1 , the gene encoding the α1 subunit of the Na + /K + -ATPase (NKA), have been linked to diseases including primary hyperaldosteronism and the peripheral neuropathy Charcot-Marie-Tooth disease (CMT). ATP1A1 variants that cause CMT induce loss-of-function of NKA. This heterodimeric (αβ) enzyme hydrolyzes ATP to establish transmembrane electrochemical gradients of Na + and K + that are essential for electrical signaling and cell survival. Of the 4 catalytic subunit isoforms, α1 is ubiquitously expressed and is the predominant paralog in peripheral axons. Human population sequencing datasets indicate strong negative selection against both missense and protein-null ATP1A1 variants. To test whether haploinsufficiency generated by heterozygous protein-null alleles are sufficient to cause disease, we tested the neuromuscular characteristics of heterozygous Atp1a1 +/- knockout mice and their wildtype littermates, while also evaluating if exercise increased CMT penetrance. We found that Atp1a1 +/- mice were phenotypically normal up to 18 months of age. Consistent with the observations in mice, we report clinical phenotyping of a healthy adult human who lacks any clinical features of known ATP1A1 -related diseases despite carrying a protein-null early truncation variant, p.Y148*. Taken together, these results suggest that a malfunctioning gene product is required for disease induction by ATP1A1 variants and that if any pathology is associated with protein-null variants, they may display low penetrance or high age of onset.
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10
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Chernova I, Song W, Steach H, Hafez O, Al Souz J, Chen PM, Chandra N, Cantley L, Veselits M, Clark MR, Craft J. The ion transporter Na +-K +-ATPase enables pathological B cell survival in the kidney microenvironment of lupus nephritis. SCIENCE ADVANCES 2023; 9:eadf8156. [PMID: 36724234 PMCID: PMC9891690 DOI: 10.1126/sciadv.adf8156] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The kidney is a comparatively hostile microenvironment characterized by highsodium concentrations; however, lymphocytes infiltrate and survive therein in autoimmune diseases such as lupus. The effects of sodium-lymphocyte interactions on tissue injury in autoimmune diseases and the mechanisms used by infiltrating lymphocytes to survive the highsodium environment of the kidney are not known. Here, we show that kidney-infiltrating B cells in lupus adapt to elevated sodium concentrations and that expression of sodium potassium adenosine triphosphatase (Na+-K+-ATPase) correlates with the ability of infiltrating cells to survive. Pharmacological inhibition of Na+-K+-ATPase and genetic knockout of Na+-K+-ATPase γ subunit resulted in reduced B cell infiltration into kidneys and amelioration of proteinuria. B cells in human lupus nephritis biopsies also had high expression of Na+-K+-ATPase. Our study reveals that kidney-infiltrating B cells in lupus initiate a tissue adaption program in response to sodium stress and identifies Na+-K+-ATPase as an organ-specific therapeutic target.
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Affiliation(s)
- Irene Chernova
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
- Corresponding author. (I.C.); (J.C.)
| | - Wenzhi Song
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Holly Steach
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Omeed Hafez
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Jafar Al Souz
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Ping-Min Chen
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Nisha Chandra
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Lloyd Cantley
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Margaret Veselits
- Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, Departments of Medicine and Pathology, University of Chicago, Chicago, IL, USA
| | - Marcus R. Clark
- Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, Departments of Medicine and Pathology, University of Chicago, Chicago, IL, USA
| | - Joe Craft
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
- Corresponding author. (I.C.); (J.C.)
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11
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Meyer DJ, Díaz-García CM, Nathwani N, Rahman M, Yellen G. The Na +/K + pump dominates control of glycolysis in hippocampal dentate granule cells. eLife 2022; 11:e81645. [PMID: 36222651 PMCID: PMC9592084 DOI: 10.7554/elife.81645] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
Cellular ATP that is consumed to perform energetically expensive tasks must be replenished by new ATP through the activation of metabolism. Neuronal stimulation, an energetically demanding process, transiently activates aerobic glycolysis, but the precise mechanism underlying this glycolysis activation has not been determined. We previously showed that neuronal glycolysis is correlated with Ca2+ influx, but is not activated by feedforward Ca2+ signaling (Díaz-García et al., 2021a). Since ATP-powered Na+ and Ca2+ pumping activities are increased following stimulation to restore ion gradients and are estimated to consume most neuronal ATP, we aimed to determine if they are coupled to neuronal glycolysis activation. By using two-photon imaging of fluorescent biosensors and dyes in dentate granule cell somas of acute mouse hippocampal slices, we observed that production of cytoplasmic NADH, a byproduct of glycolysis, is strongly coupled to changes in intracellular Na+, while intracellular Ca2+ could only increase NADH production if both forward Na+/Ca2+ exchange and Na+/K+ pump activity were intact. Additionally, antidromic stimulation-induced intracellular [Na+] increases were reduced >50% by blocking Ca2+ entry. These results indicate that neuronal glycolysis activation is predominantly a response to an increase in activity of the Na+/K+ pump, which is strongly potentiated by Na+ influx through the Na+/Ca2+ exchanger during extrusion of Ca2+ following stimulation.
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Affiliation(s)
- Dylan J Meyer
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | | | - Nidhi Nathwani
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Mahia Rahman
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Gary Yellen
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
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12
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Deficiency in FTSJ1 Affects Neuronal Plasticity in the Hippocampal Formation of Mice. BIOLOGY 2022; 11:biology11071011. [PMID: 36101392 PMCID: PMC9312013 DOI: 10.3390/biology11071011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/01/2022] [Accepted: 07/03/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Neuronal plasticity refers to the brain’s ability to adapt in response to activity-dependent changes. This process, among others, allows the brain to acquire memory or to compensate for a neurocognitive deficit. We analyzed adult FTSJ1-deficient mice in order to gain insight into the role of FTSJ1 in neuronal plasticity. These mice displayed alterations in the hippocampus (a brain structure that is involved in memory and learning, among other functions) e.g., in the form of changes in dendritic spines. Changes in dendritic spines are considered to represent a morphological hallmark of altered neuronal plasticity, and thus FTSJ1 deficiency might have a direct effect upon the capacity of the brain to adapt to plastic changes. Long-term potentiation (LTP) is an electrophysiological correlate of neuronal plasticity, and is related to learning and to processes attributed to memory. Here we show that LTP in FTSJ1-deficient mice is reduced, hinting at disturbed neuronal plasticity. These findings suggest that FTSJ1 deficiency has an impact on neuronal plasticity not only morphologically but also on the physiological level. Abstract The role of the tRNA methyltransferase FTSJ1 in the brain is largely unknown. We analyzed whether FTSJ1-deficient mice (KO) displayed altered neuronal plasticity. We explored open field behavior (10 KO mice (aged 22–25 weeks)) and 11 age-matched control littermates (WT) and examined mean layer thickness (7 KO; 6 WT) and dendritic spines (5 KO; 5 WT) in the hippocampal area CA1 and the dentate gyrus. Furthermore, long-term potentiation (LTP) within area CA1 was investigated (5 KO; 5 WT), and mass spectrometry (MS) using CA1 tissue (2 each) was performed. Compared to controls, KO mice showed a significant reduction in the mean thickness of apical CA1 layers. Dendritic spine densities were also altered in KO mice. Stable LTP could be induced in the CA1 area of KO mice and remained stable at for at least 1 h, although at a lower level as compared to WTs, while MS data indicated differential abundance of several proteins, which play a role in neuronal plasticity. FTSJ1 has an impact on neuronal plasticity in the murine hippocampal area CA1 at the morphological and physiological levels, which, in conjunction with comparable changes in other cortical areas, might accumulate in disturbed learning and memory functions.
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13
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Spontarelli K, Infield DT, Nielsen HN, Holm R, Young VC, Galpin JD, Ahern CA, Vilsen B, Artigas P. Role of a conserved ion-binding site tyrosine in ion selectivity of the Na+/K+ pump. J Gen Physiol 2022; 154:e202113039. [PMID: 35657726 PMCID: PMC9171065 DOI: 10.1085/jgp.202113039] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 04/19/2022] [Accepted: 05/16/2022] [Indexed: 01/07/2023] Open
Abstract
The essential transmembrane Na+ and K+ gradients in animal cells are established by the Na+/K+ pump, a P-type ATPase that exports three Na+ and imports two K+ per ATP hydrolyzed. The mechanism by which the Na+/K+ pump distinguishes between Na+ and K+ at the two membrane sides is poorly understood. Crystal structures identify two sites (sites I and II) that bind Na+ or K+ and a third (site III) specific for Na+. The side chain of a conserved tyrosine at site III of the catalytic α-subunit (Xenopus-α1 Y780) has been proposed to contribute to Na+ binding by cation-π interaction. We substituted Y780 with natural and unnatural amino acids, expressed the mutants in Xenopus oocytes and COS-1 cells, and used electrophysiology and biochemistry to evaluate their function. Substitutions disrupting H-bonds impaired Na+ interaction, while Y780Q strengthened it, likely by H-bond formation. Utilizing the non-sense suppression method previously used to incorporate unnatural derivatives in ion channels, we were able to analyze Na+/K+ pumps with fluorinated tyrosine or phenylalanine derivatives inserted at position 780 to diminish cation-π interaction strength. In line with the results of the analysis of mutants with natural amino acid substitutions, the results with the fluorinated derivatives indicate that Na+-π interaction with the phenol ring at position 780 contributes minimally, if at all, to the binding of Na+. All Y780 substitutions decreased K+ apparent affinity, highlighting that a state-dependent H-bond network is essential for the selectivity switch at sites I and II when the pump changes conformational state.
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Affiliation(s)
- Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Daniel T. Infield
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Hang N. Nielsen
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Rikke Holm
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Victoria C. Young
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Jason D. Galpin
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Christopher A. Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Bente Vilsen
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
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14
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Zhang Z, Tang Y, Li L, Yang W, Xu Y, Zhou J, Ma K, Zhang K, Zhuang H, Gong Y, Gong K. Downregulation of FXYD2 Is Associated with Poor Prognosis and Increased Regulatory T Cell Infiltration in Clear Cell Renal Cell Carcinoma. J Immunol Res 2022; 2022:4946197. [PMID: 36313180 PMCID: PMC9606837 DOI: 10.1155/2022/4946197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/15/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND FXYD2, a gene coding for the γ subunit of Na+/K+-ATPase, was demonstrated to involve in carcinogenesis recently. However, the specific role of FXYD2 in clear cell renal cell carcinoma (ccRCC) remains unknown. The current study was conducted to investigate the expression, biological function, and potentially immune-related mechanisms of FXYD2 in ccRCC. Materials and methods. The data from TCGA-KIRC, ICGC, GEO, Oncomine, ArrayExpress, TIMER, HPA datasets, and our clinical samples were used to determine and validate the expression level, prognostic roles, and potentially immune-related mechanisms in ccRCC. Cell function assays were performed to investigate the biological role of FXYD2 in vitro. RESULTS FXYD2 was identified to be downregulated in ccRCC tissue compared to normal tissue, which was confirmed by our RT-PCR, WB, and IHC analyses. Kaplan-Meier survival analysis and Cox regression analysis suggested that downregulated FXYD2 could independently predict poor survival of ccRCC patients. Through the ESTIMATE algorithm, ssGSEA algorithm, CIBERSORT algorithm, TIMER database, and our laboratory experiment, FXYD2 was found to correlate with the immune landscape, especially regulatory T cells (Treg), in ccRCC. Gain-of-function experiment revealed that FXYD2 could restrain cell proliferation, migration, and invasion in vitro. Functional enrichment analysis illustrated that TGF-β-SMAD2/3, Notch, and PI3K-Akt-mTOR signaling pathways may be potential signaling pathways of FXYD2 in ccRCC. CONCLUSIONS Downregulation of FXYD2 is associated with ccRCC tumorigenesis, poor prognosis, and increased Treg infiltration in ccRCC, which may be related to TGF-β-SMAD2/3, Notch, and PI3K-Akt-mTOR signaling pathways. This will probably provide a novel prognostic marker and potential therapeutic target for ccRCC.
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Affiliation(s)
- Zedan Zhang
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Yanlin Tang
- Shantou University Medical College, Shantou, China
| | - Lei Li
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Wuping Yang
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Yawei Xu
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Jingcheng Zhou
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Kaifang Ma
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Kenan Zhang
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Hongkai Zhuang
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yanqing Gong
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
| | - Kan Gong
- Department of Urology, Peking University First Hospital, Beijing, China
- Hereditary Kidney Cancer Research Center, Peking University First Hospital, Beijing, China
- Institute of Urology, Peking University, Beijing, China
- National Urological Cancer Center, Beijing, China
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15
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Biondo ED, Spontarelli K, Ababioh G, Méndez L, Artigas P. Diseases caused by mutations in the Na +/K + pump α1 gene ATP1A1. Am J Physiol Cell Physiol 2021; 321:C394-C408. [PMID: 34232746 DOI: 10.1152/ajpcell.00059.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human cell survival requires function of the Na+/K+ pump; the heteromeric protein that hydrolyzes ATP to extrude Na+ and import K+ across the plasmalemma, thereby building and maintaining these ions' electrochemical gradients. Numerous dominant diseases caused by mutations in genes encoding for Na+/K+ pump catalytic (α) subunit isoforms highlight the importance of this protein. Here, we review literature describing disorders caused by missense mutations in ATP1A1, the gene encoding the ubiquitously expressed α1 isoform of the Na+/K+ pump. These various maladies include primary aldosteronism with secondary hypertension, an endocrine syndrome, Charcot-Marie-Tooth disease, a peripheral neuropathy, complex spastic paraplegia, another neuromuscular disorder, as well as hypomagnesemia accompanied by seizures and cognitive delay, a condition affecting the renal and central nervous systems. This article focuses on observed commonalities among these mutations' functional effects, as well as on the special characteristics that enable each particular mutation to exclusively affect a certain system, without affecting others. In this respect, it is clear how somatic mutations localized to adrenal adenomas increase aldosterone production without compromising other systems. However, it remains largely unknown how and why some but not all de novo germline or familial mutations (where the mutant must be expressed in numerous tissues) produce a specific disease and not the other diseases. We propose hypotheses to explain this observation and the approaches that we think will drive future research on these debilitating disorders to develop novel patient-specific treatments by combining the use of heterologous protein-expression systems, patient-derived pluripotent cells, and gene-edited cell and mouse models.
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Affiliation(s)
- Elisa D Biondo
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Giovanna Ababioh
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Lois Méndez
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
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16
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Habeck M, Poulsen H. What FXYDs fix. J Gen Physiol 2021; 153:212005. [PMID: 33871566 PMCID: PMC8059070 DOI: 10.1085/jgp.202012845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Michael Habeck
- Danish Research Institute of Translational Neuroscience and the Center for Proteins in Memory, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Hanne Poulsen
- Danish Research Institute of Translational Neuroscience and the Center for Proteins in Memory, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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17
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Yap JQ, Seflova J, Sweazey R, Artigas P, Robia SL. FXYD proteins and sodium pump regulatory mechanisms. J Gen Physiol 2021; 153:211866. [PMID: 33688925 PMCID: PMC7953255 DOI: 10.1085/jgp.202012633] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
The sodium/potassium-ATPase (NKA) is the enzyme that establishes gradients of sodium and potassium across the plasma membrane. NKA activity is tightly regulated for different physiological contexts through interactions with single-span transmembrane peptides, the FXYD proteins. This diverse family of regulators has in common a domain containing a Phe-X-Tyr-Asp (FXYD) motif, two conserved glycines, and one serine residue. In humans, there are seven tissue-specific FXYD proteins that differentially modulate NKA kinetics as appropriate for each system, providing dynamic responsiveness to changing physiological conditions. Our understanding of how FXYD proteins contribute to homeostasis has benefitted from recent advances described in this review: biochemical and biophysical studies have provided insight into regulatory mechanisms, genetic models have uncovered remarkable complexity of FXYD function in integrated physiological systems, new posttranslational modifications have been identified, high-resolution structural studies have revealed new details of the regulatory interaction with NKA, and new clinical correlations have been uncovered. In this review, we address the structural determinants of diverse FXYD functions and the special roles of FXYDs in various physiological systems. We also discuss the possible roles of FXYDs in protein trafficking and regulation of non-NKA targets.
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Affiliation(s)
- John Q Yap
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Ryan Sweazey
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
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