1
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Matsell E, Andersen JP, Molday RS. Functional and in silico analysis of ATP8A2 and other P4-ATPase variants associated with human genetic diseases. Dis Model Mech 2024; 17:dmm050546. [PMID: 38436085 PMCID: PMC11073571 DOI: 10.1242/dmm.050546] [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: 10/10/2023] [Accepted: 02/21/2024] [Indexed: 03/05/2024] Open
Abstract
P4-ATPases flip lipids from the exoplasmic to cytoplasmic leaflet of cell membranes, a property crucial for many biological processes. Mutations in P4-ATPases are associated with severe inherited and complex human disorders. We determined the expression, localization and ATPase activity of four variants of ATP8A2, the P4-ATPase associated with the neurodevelopmental disorder known as cerebellar ataxia, impaired intellectual development and disequilibrium syndrome 4 (CAMRQ4). Two variants, G447R and A772P, harboring mutations in catalytic domains, expressed at low levels and mislocalized in cells. In contrast, the E459Q variant in a flexible loop displayed wild-type expression levels, Golgi-endosome localization and ATPase activity. The R1147W variant expressed at 50% of wild-type levels but showed normal localization and activity. These results indicate that the G447R and A772P mutations cause CAMRQ4 through protein misfolding. The E459Q mutation is unlikely to be causative, whereas the R1147W may display a milder disease phenotype. Using various programs that predict protein stability, we show that there is a good correlation between the experimental expression of the variants and in silico stability assessments, suggesting that such analysis is useful in identifying protein misfolding disease-associated variants.
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Affiliation(s)
- Eli Matsell
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | - Robert S. Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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2
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Duan HD, Li H. Consensus, controversies, and conundrums of P4-ATPases: The emerging face of eukaryotic lipid flippases. J Biol Chem 2024; 300:107387. [PMID: 38763336 PMCID: PMC11225554 DOI: 10.1016/j.jbc.2024.107387] [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: 03/26/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/21/2024] Open
Abstract
The cryo-EM resolution revolution has heralded a new era in our understanding of eukaryotic lipid flippases with a rapidly growing number of high-resolution structures. Flippases belong to the P4 family of ATPases (type IV P-type ATPases) that largely follow the reaction cycle proposed for the more extensively studied cation-transporting P-type ATPases. However, unlike the canonical P-type ATPases, no flippase cargos are transported in the phosphorylation half-reaction. Instead of being released into the intracellular or extracellular milieu, lipid cargos are transported to their destination at the inner leaflet of the membrane. Recent flippase structures have revealed multiple conformational states during the lipid transport cycle. Nonetheless, critical conformational states capturing the lipid cargo "in transit" are still missing. In this review, we highlight the amazing structural advances of these lipid transporters, discuss various perspectives on catalytic and regulatory mechanisms in the literature, and shed light on future directions in further deciphering the detailed molecular mechanisms of lipid flipping.
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Affiliation(s)
- H Diessel Duan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA.
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3
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Park S, Noblett N, Pitts L, Colavita A, Wehman AM, Jin Y, Chisholm AD. Dopey-dependent regulation of extracellular vesicles maintains neuronal morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.591898. [PMID: 38766017 PMCID: PMC11100700 DOI: 10.1101/2024.05.07.591898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Mature neurons maintain their distinctive morphology for extended periods in adult life. Compared to developmental neurite outgrowth, axon guidance, and target selection, relatively little is known of mechanisms that maintain mature neuron morphology. Loss of function in C. elegans DIP-2, a member of the conserved lipid metabolic regulator Dip2 family, results in progressive overgrowth of neurites in adults. We find that dip-2 mutants display specific genetic interactions with sax-2, the C. elegans ortholog of Drosophila Furry and mammalian FRY. Combined loss of DIP-2 and SAX-2 results in severe disruption of neuronal morphology maintenance accompanied by increased release of neuronal extracellular vesicles (EVs). By screening for suppressors of dip-2 sax-2 double mutant defects we identified gain-of-function (gf) mutations in the conserved Dopey family protein PAD-1 and its associated phospholipid flippase TAT-5/ATP9A. In dip-2 sax-2 double mutants carrying either pad-1(gf) or tat-5(gf) mutation, EV release is reduced and neuronal morphology across multiple neuron types is restored to largely normal. PAD-1(gf) acts cell autonomously in neurons. The domain containing pad-1(gf) is essential for PAD-1 function, and PAD-1(gf) protein displays increased association with the plasma membrane and inhibits EV release. Our findings uncover a novel functional network of DIP-2, SAX-2, PAD-1, and TAT-5 that maintains morphology of neurons and other types of cells, shedding light on the mechanistic basis of neurological disorders involving human orthologs of these genes.
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Affiliation(s)
- Seungmee Park
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Nathaniel Noblett
- Neuroscience Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Lauren Pitts
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Antonio Colavita
- Neuroscience Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Ann M Wehman
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Yishi Jin
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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4
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Villagrana R, López-Marqués RL. Plant P4-ATPase lipid flippases: How are they regulated? BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119599. [PMID: 37741575 DOI: 10.1016/j.bbamcr.2023.119599] [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: 05/20/2023] [Revised: 08/22/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023]
Abstract
P4 ATPases are active membrane transporters that translocate lipids towards the cytosolic side of the biological membranes in eukaryotic cells. Due to their essential cellular functions, P4 ATPase activity is expected to be tightly controlled, but fundamental aspects of the regulation of plant P4 ATPases remain unstudied. In this mini-review, our knowledge of the regulatory mechanisms of yeast and mammalian P4 ATPases will be summarized, and sequence comparison and structural modelling will be used as a basis to discuss the putative regulation of the corresponding plant lipid transporters.
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Affiliation(s)
- Richard Villagrana
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Rosa Laura López-Marqués
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark.
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5
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Mogensen LS, Mikkelsen SA, Tadini-Buoninsegni F, Holm R, Matsell E, Vilsen B, Molday RS, Andersen JP. On the track of the lipid transport pathway of the phospholipid flippase ATP8A2 - Mutation analysis of residues of the transmembrane segments M1, M2, M3 and M4. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119570. [PMID: 37678495 DOI: 10.1016/j.bbamcr.2023.119570] [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: 07/03/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023]
Abstract
P4-ATPases, also known as flippases, translocate specific lipids from the exoplasmic leaflet to the cytoplasmic leaflet of biological membranes, thereby generating an asymmetric lipid distribution essential for numerous cellular functions. A debated issue is which pathway within the protein the lipid substrate follows during the translocation. Here we present a comprehensive mutational screening of all amino acid residues in the transmembrane segments M1, M2, M3, and M4 of the flippase ATP8A2, thus allowing the functionally important residues in these transmembrane segments to be highlighted on a background of less important residues. Kinetic analysis of ATPase activity of 130 new ATP8A2 mutants, providing Vmax values as well as apparent affinities of the mutants for the lipid substrate, support a translocation pathway between M2 and M4 ("M2-M4 path"), extending from the entry site, where the lipid substrate binds from the exoplasmic leaflet, to a putative exit site at the cytoplasmic surface, formed by the divergence of M2 and M4. The effects of mutations in the M2-M4 path on the function of the entry site, including loss of lipid specificity in some mutants, suggest that the M2-M4 path and the entry site are conformationally coupled. Many of the residues of the M2-M4 path possess side chains with a potential for interacting with each other in a zipper-like mode, as well as with the head group of the lipid substrate, by ionic/hydrogen bonds. Thus, the translocation of the lipid substrate toward the cytoplasmic bilayer leaflet is comparable to unzipping a zipper of salt bridges/hydrogen bonds.
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Affiliation(s)
| | | | | | - Rikke Holm
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Eli Matsell
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bente Vilsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada; Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Young MR, Heit S, Bublitz M. Structure, function and biogenesis of the fungal proton pump Pma1. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119600. [PMID: 37741574 DOI: 10.1016/j.bbamcr.2023.119600] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/19/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023]
Abstract
The fungal plasma membrane proton pump Pma1 is an integral plasma membrane protein of the P-type ATPase family. It is an essential enzyme responsible for maintaining a constant cytosolic pH and for energising the plasma membrane to secondary transport processes. Due to its importance for fungal survival and absence from animals, Pma1 is also a highly sought-after drug target. Until recently, its characterisation has been limited to functional, mutational and localisation studies, due to a lack of high-resolution structural information. The determination of three cryo-EM structures of Pma1 in its unique hexameric state offers a new level of understanding the molecular mechanisms underlying the protein's stability, regulated activity and druggability. In light of this context, this article aims to review what we currently know about the structure, function and biogenesis of fungal Pma1.
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Affiliation(s)
- Margaret R Young
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Maike Bublitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
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7
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Herrera SA, Justesen BH, Dieudonné T, Montigny C, Nissen P, Lenoir G, Günther Pomorski T. Direct evidence of lipid transport by the Drs2-Cdc50 flippase upon truncation of its terminal regions. Protein Sci 2023; 33:e4855. [PMID: 38063271 PMCID: PMC10895448 DOI: 10.1002/pro.4855] [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: 08/19/2023] [Revised: 11/15/2023] [Accepted: 12/02/2023] [Indexed: 02/27/2024]
Abstract
P4-ATPases in complex with Cdc50 subunits are lipid flippases that couple ATP hydrolysis with lipid transport to the cytoplasmic leaflet of membranes to create lipid asymmetry. Such vectorial transport has been shown to contribute to vesicle formation in the late secretory pathway. Some flippases are regulated by autoinhibitory regions that can be destabilized by protein kinase-mediated phosphorylation and possibly by binding of cytosolic proteins. In addition, the binding of lipids to flippases may also induce conformational changes required for the activity of these transporters. Here, we address the role of phosphatidylinositol-4-phosphate (PI4P) and the terminal autoinhibitory tails on the lipid flipping activity of the yeast lipid flippase Drs2-Cdc50. By functionally reconstituting the full-length and truncated forms of Drs2 in a 1:1 complex with the Cdc50 subunit, we provide compelling evidence that lipid flippase activity is exclusively detected for the truncated Drs2 variant and is dependent on the presence of the phosphoinositide PI4P. These findings highlight the critical role of phosphoinositides as lipid co-factors in the regulation of lipid transport by the Drs2-Cdc50 flippase.
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Affiliation(s)
- Sara Abad Herrera
- Department of Molecular Biochemistry, Faculty of Chemistry and BiochemistryRuhr University BochumBochumGermany
| | - Bo Højen Justesen
- Department of Molecular Biochemistry, Faculty of Chemistry and BiochemistryRuhr University BochumBochumGermany
| | - Thibaud Dieudonné
- Université Paris‐Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Gif‐sur‐YvetteFrance
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Cédric Montigny
- Université Paris‐Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Gif‐sur‐YvetteFrance
| | - Poul Nissen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Guillaume Lenoir
- Université Paris‐Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)Gif‐sur‐YvetteFrance
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and BiochemistryRuhr University BochumBochumGermany
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksbergDenmark
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8
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Dieudonné T, Kümmerer F, Laursen MJ, Stock C, Flygaard RK, Khalid S, Lenoir G, Lyons JA, Lindorff-Larsen K, Nissen P. Activation and substrate specificity of the human P4-ATPase ATP8B1. Nat Commun 2023; 14:7492. [PMID: 37980352 PMCID: PMC10657443 DOI: 10.1038/s41467-023-42828-9] [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: 04/12/2023] [Accepted: 10/23/2023] [Indexed: 11/20/2023] Open
Abstract
Asymmetric distribution of phospholipids in eukaryotic membranes is essential for cell integrity, signaling pathways, and vesicular trafficking. P4-ATPases, also known as flippases, participate in creating and maintaining this asymmetry through active transport of phospholipids from the exoplasmic to the cytosolic leaflet. Here, we present a total of nine cryo-electron microscopy structures of the human flippase ATP8B1-CDC50A complex at 2.4 to 3.1 Å overall resolution, along with functional and computational studies, addressing the autophosphorylation steps from ATP, substrate recognition and occlusion, as well as a phosphoinositide binding site. We find that the P4-ATPase transport site is occupied by water upon phosphorylation from ATP. Additionally, we identify two different autoinhibited states, a closed and an outward-open conformation. Furthermore, we identify and characterize the PI(3,4,5)P3 binding site of ATP8B1 in an electropositive pocket between transmembrane segments 5, 7, 8, and 10. Our study also highlights the structural basis of a broad lipid specificity of ATP8B1 and adds phosphatidylinositol as a transport substrate for ATP8B1. We report a critical role of the sn-2 ester bond of glycerophospholipids in substrate recognition by ATP8B1 through conserved S403. These findings provide fundamental insights into ATP8B1 catalytic cycle and regulation, and substrate recognition in P4-ATPases.
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Affiliation(s)
- Thibaud Dieudonné
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Felix Kümmerer
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Michelle Juknaviciute Laursen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Charlott Stock
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Rasmus Kock Flygaard
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Joseph A Lyons
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
- Interdisciplinary Nanoscience Centre (iNANO) Aarhus University, Aarhus, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Poul Nissen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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9
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Rivera-Morán MA, Sampedro JG. Isolation of the Sarcoplasmic Reticulum Ca 2+-ATPase from Rabbit Fast-Twitch Muscle. Methods Protoc 2023; 6:102. [PMID: 37888034 PMCID: PMC10608927 DOI: 10.3390/mps6050102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023] Open
Abstract
The sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) is a membrane protein that is destabilized during purification in the absence of calcium ions. The disaccharide trehalose is a protein stabilizer that accumulates in the yeast cytoplasm when under stress. In the present work, SERCA was purified by including trehalose in the purification protocol. The purified SERCA showed high protein purity (~95%) and ATPase activity. ATP hydrolysis was dependent on the presence of Ca2+ and the enzyme kinetics showed a hyperbolic dependence on ATP (Km = 12.16 ± 2.25 μM ATP). FITC labeling showed the integrity of the ATP-binding site and the identity of the isolated enzyme as a P-type ATPase. Circular dichroism (CD) spectral changes at a wavelength of 225 nm were observed upon titration with ATP, indicating α-helical rearrangements in the nucleotide-binding domain (N-domain), which correlated with ATP affinity (Km). The presence of Ca2+ did not affect FITC labeling or the ATP-mediated structural changes at the N-domain. The use of trehalose in the SERCA purification protocol stabilized the enzyme. The isolated SERCA appears to be suitable for structural and ligand binding studies, e.g., for testing newly designed or natural inhibitors. The use of trehalose is recommended for the isolation of unstable enzymes.
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Affiliation(s)
| | - José G. Sampedro
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Avenida Chapultepec 1570, Privadas del Pedregal, San Luis Potosí 78295, Mexico
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10
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Herrera SA, Günther Pomorski T. Reconstitution of ATP-dependent lipid transporters: gaining insight into molecular characteristics, regulation, and mechanisms. Biosci Rep 2023; 43:BSR20221268. [PMID: 37417269 PMCID: PMC10412526 DOI: 10.1042/bsr20221268] [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: 04/26/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 07/08/2023] Open
Abstract
Lipid transporters play a crucial role in supporting essential cellular processes such as organelle assembly, vesicular trafficking, and lipid homeostasis by driving lipid transport across membranes. Cryo-electron microscopy has recently resolved the structures of several ATP-dependent lipid transporters, but functional characterization remains a major challenge. Although studies of detergent-purified proteins have advanced our understanding of these transporters, in vitro evidence for lipid transport is still limited to a few ATP-dependent lipid transporters. Reconstitution into model membranes, such as liposomes, is a suitable approach to study lipid transporters in vitro and to investigate their key molecular features. In this review, we discuss the current approaches for reconstituting ATP-driven lipid transporters into large liposomes and common techniques used to study lipid transport in proteoliposomes. We also highlight the existing knowledge on the regulatory mechanisms that modulate the activity of lipid transporters, and finally, we address the limitations of the current approaches and future perspectives in this field.
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Affiliation(s)
- Sara Abad Herrera
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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11
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Čopič A, Dieudonné T, Lenoir G. Phosphatidylserine transport in cell life and death. Curr Opin Cell Biol 2023; 83:102192. [PMID: 37413778 DOI: 10.1016/j.ceb.2023.102192] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023]
Abstract
Phosphatidylserine (PS) is a negatively charged glycerophospholipid found mainly in the plasma membrane (PM) and in the late secretory/endocytic compartments, where it regulates cellular activity and can mediate apoptosis. Export of PS from the endoplasmic reticulum, its site of synthesis, to other compartments, and its transbilayer asymmetry must therefore be precisely regulated. We review recent findings on nonvesicular transport of PS by lipid transfer proteins (LTPs) at membrane contact sites, on PS flip-flop between membrane leaflets by flippases and scramblases, and on PS nanoclustering at the PM. We also discuss emerging data on cooperation between scramblases and LTPs, how perturbation of PS distribution can lead to disease, and the specific role of PS in viral infection.
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Affiliation(s)
- Alenka Čopič
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293, Montpellier CEDEX 05, France.
| | - Thibaud Dieudonné
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette 91198, France
| | - Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette 91198, France
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12
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Sakuragi T, Nagata S. Regulation of phospholipid distribution in the lipid bilayer by flippases and scramblases. Nat Rev Mol Cell Biol 2023:10.1038/s41580-023-00604-z. [PMID: 37106071 PMCID: PMC10134735 DOI: 10.1038/s41580-023-00604-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2023] [Indexed: 04/29/2023]
Abstract
Cellular membranes function as permeability barriers that separate cells from the external environment or partition cells into distinct compartments. These membranes are lipid bilayers composed of glycerophospholipids, sphingolipids and cholesterol, in which proteins are embedded. Glycerophospholipids and sphingolipids freely move laterally, whereas transverse movement between lipid bilayers is limited. Phospholipids are asymmetrically distributed between membrane leaflets but change their location in biological processes, serving as signalling molecules or enzyme activators. Designated proteins - flippases and scramblases - mediate this lipid movement between the bilayers. Flippases mediate the confined localization of specific phospholipids (phosphatidylserine (PtdSer) and phosphatidylethanolamine) to the cytoplasmic leaflet. Scramblases randomly scramble phospholipids between leaflets and facilitate the exposure of PtdSer on the cell surface, which serves as an important signalling molecule and as an 'eat me' signal for phagocytes. Defects in flippases and scramblases cause various human diseases. We herein review the recent research on the structure of flippases and scramblases and their physiological roles. Although still poorly understood, we address the mechanisms by which they translocate phospholipids between lipid bilayers and how defects cause human diseases.
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Affiliation(s)
- Takaharu Sakuragi
- Biochemistry & Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Shigekazu Nagata
- Biochemistry & Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan.
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13
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Zhang H, Zhang Y, Xu P, Bai C. Exploring the Phospholipid Transport Mechanism of ATP8A1-CDC50. Biomedicines 2023; 11:biomedicines11020546. [PMID: 36831082 PMCID: PMC9953615 DOI: 10.3390/biomedicines11020546] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
P4-ATPase translocates lipids from the exoplasmic to the cytosolic plasma membrane leaflet to maintain lipid asymmetry distribution in eukaryotic cells. P4-ATPase is associated with severe neurodegenerative and metabolic diseases such as neurological and motor disorders. Thus, it is important to understand its transport mechanism. However, even with progress in X-ray diffraction and cryo-electron microscopy techniques, it is difficult to obtain the dynamic information of the phospholipid transport process in detail. There are still some problems required to be resolved: (1) when does the lipid transport happen? (2) How do the key residues on the transmembrane helices contribute to the free energy of important states? In this work, we explore the phospholipid transport mechanism using a coarse-grained model and binding free energy calculations. We obtained the free energy landscape by coupling the protein conformational changes and the phospholipid transport event, taking ATP8A1-CDC50 (the typical subtype of P4-ATPase) as the research object. According to the results, we found that the phospholipid would bind to the ATP8A1-CDC50 at the early stage when ATP8A1-CDC50 changes from E2P to E2Pi-PL state. We also found that the electrostatic effects play crucial roles in the phospholipid transport process. The information obtained from this work could help us in designing novel drugs for P-type flippase disorders.
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Affiliation(s)
- Honghui Zhang
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China
| | - Yue Zhang
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Peiyi Xu
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China
| | - Chen Bai
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China
- Chenzhu (MoMeD) Biotechnology Co., Ltd., Hangzhou 310005, China
- Correspondence:
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Functional Analysis of the P-Type ATPases Apt2-4 from Cryptococcus neoformans by Heterologous Expression in Saccharomyces cerevisiae. J Fungi (Basel) 2023; 9:jof9020202. [PMID: 36836316 PMCID: PMC9966271 DOI: 10.3390/jof9020202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/09/2023] Open
Abstract
Lipid flippases of the P4-ATPase family actively transport phospholipids across cell membranes, an activity essential for key cellular processes such as vesicle budding and membrane trafficking. Members of this transporter family have also been implicated in the development of drug resistance in fungi. The encapsulated fungal pathogen Cryptococcus neoformans contains four P4-ATPases, among which Apt2-4p are poorly characterized. Using heterologous expression in the flippase-deficient S. cerevisiae strain dnf1Δdnf2Δdrs2Δ, we tested their lipid flippase activity in comparison to Apt1p using complementation tests and fluorescent lipid uptake assays. Apt2p and Apt3p required the co-expression of the C. neoformans Cdc50 protein for activity. Apt2p/Cdc50p displayed a narrow substrate specificity, limited to phosphatidylethanolamine and -choline. Despite its inability to transport fluorescent lipids, the Apt3p/Cdc50p complex still rescued the cold-sensitive phenotype of dnf1Δdnf2Δdrs2Δ, suggesting a functional role for the flippase in the secretory pathway. Apt4p, the closest homolog to Saccharomyces Neo1p, which does not require a Cdc50 protein, was unable to complement several flippase-deficient mutant phenotypes, neither in the presence nor absence of a β-subunit. These results identify C. neoformans Cdc50 as an essential subunit for Apt1-3p and provide a first insight into the molecular mechanisms underlying their physiological functions.
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15
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Li J, Zhao Y, Wang N. Physiological and Pathological Functions of TMEM30A: An Essential Subunit of P4-ATPase Phospholipid Flippases. J Lipids 2023; 2023:4625567. [PMID: 37200892 PMCID: PMC10188266 DOI: 10.1155/2023/4625567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/28/2023] [Accepted: 04/15/2023] [Indexed: 05/20/2023] Open
Abstract
Phospholipids are asymmetrically distributed across mammalian plasma membrane. The function of P4-ATPases is to maintain the abundance of phosphatidylserine (PS) and phosphatidylethanolamine (PE) in the inner leaflet as lipid flippases. Transmembrane protein 30A (TMEM30A, also named CDC50A), as an essential β subunit of most P4-ATPases, facilitates their transport and functions. With TMEM30A knockout mice or cell lines, it is found that the loss of TMEM30A has huge influences on the survival of mice and cells because of PS exposure-triggered apoptosis signaling. TMEM30A is a promising target for drug discovery due to its significant roles in various systems and diseases. In this review, we summarize the functions of TMEM30A in different systems, present current understanding of the protein structures and mechanisms of TMEM30A-P4-ATPase complexes, and discuss how these fundamental aspects of TMEM30A may be applied to disease treatment.
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Affiliation(s)
- Jingyi Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Yue Zhao
- Clinical Medical Laboratory, Wenjiang Hospital of Sichuan Provincial People's Hospital, Chengdu, China
| | - Na Wang
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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16
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Dieudonné T, Jaxel C, Lejeune M, Lenoir G, Montigny C. Expression in Saccharomyces cerevisiae and Purification of a Human Phospholipid Flippase. Methods Mol Biol 2023; 2652:231-246. [PMID: 37093479 DOI: 10.1007/978-1-0716-3147-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Membrane proteins (MPs) are challenging to study from a biochemical standpoint owing to the difficulties associated with the isolation of these proteins from the membranes they are embedded in. Even for the expression of closely-related homologues, protocols often require to be adjusted. Prominently, the solubilization step and the stabilization of recombinant proteins during the purification process are key issues, and remain a serious bottleneck. Here, we present a method for the expression and the purification of the human ATP8B1/CDC50A lipid flippase complex. Selection of the right Saccharomyces cerevisiae strain proved to be a critical step for the successful purification of this complex. Likewise, the use of cholesteryl hemisuccinate, a cholesterol analogue, contributed to significantly increase the yield of purification. We hope that the simple method described here can help researchers to succeed in the expression of other mammalian difficult-to-express lipid flippases and, by extension, help in the production of other membrane proteins whose isolation has so far proven difficult.
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Affiliation(s)
- Thibaud Dieudonné
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
| | - Christine Jaxel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Maylis Lejeune
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Institut Pasteur, Université de Paris, CNRS UMR3528, Structural Bioinformatics Unit, Paris, France
| | - Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
| | - Cédric Montigny
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
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17
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Gómez-Mellado VE, Chang JC, Ho-Mok KS, Bernardino Morcillo C, Kersten RHJ, Oude Elferink RPJ, Verhoeven AJ, Paulusma CC. ATP8B1 Deficiency Results in Elevated Mitochondrial Phosphatidylethanolamine Levels and Increased Mitochondrial Oxidative Phosphorylation in Human Hepatoma Cells. Int J Mol Sci 2022; 23:ijms232012344. [PMID: 36293199 PMCID: PMC9604224 DOI: 10.3390/ijms232012344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/20/2022] Open
Abstract
ATP8B1 is a phospholipid flippase that is deficient in patients with progressive familial intrahepatic cholestasis type 1 (PFIC1). PFIC1 patients suffer from severe liver disease but also present with dyslipidemia, including low plasma cholesterol, of yet unknown etiology. Here we show that ATP8B1 knockdown in HepG2 cells leads to a strong increase in the mitochondrial oxidative phosphorylation (OXPHOS) without a change in glycolysis. The enhanced OXPHOS coincides with elevated low-density lipoprotein receptor protein and increased mitochondrial fragmentation and phosphatidylethanolamine levels. Furthermore, expression of phosphatidylethanolamine N-methyltransferase, an enzyme that catalyzes the conversion of mitochondrial-derived phosphatidylethanolamine to phosphatidylcholine, was reduced in ATP8B1 knockdown cells. We conclude that ATP8B1 deficiency results in elevated mitochondrial PE levels that stimulate mitochondrial OXPHOS. The increased OXPHOS leads to elevated LDLR levels, which provides a possible explanation for the reduced plasma cholesterol levels in PFIC1 disease.
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Affiliation(s)
- Valentina E. Gómez-Mellado
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Jung-Chin Chang
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Kam S. Ho-Mok
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Carmen Bernardino Morcillo
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
| | - Remco H. J. Kersten
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Ronald P. J. Oude Elferink
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Arthur J. Verhoeven
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Coen C. Paulusma
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
- Correspondence:
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18
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Miyata Y, Yamada K, Nagata S, Segawa K. Two types of type IV P-type ATPases independently re-establish the asymmetrical distribution of phosphatidylserine in plasma membranes. J Biol Chem 2022; 298:102527. [PMID: 36162506 PMCID: PMC9597894 DOI: 10.1016/j.jbc.2022.102527] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 09/15/2022] [Accepted: 09/19/2022] [Indexed: 11/21/2022] Open
Abstract
Phospholipids are asymmetrically distributed between the lipid bilayer of plasma membranes in which phosphatidylserine (PtdSer) is confined to the inner leaflet. ATP11A and ATP11C, type IV P-Type ATPases in plasma membranes, flip PtdSer from the outer to the inner leaflet, but involvement of other P4-ATPases is unclear. We herein demonstrated that once PtdSer was exposed on the cell surface of ATP11A−/−ATP11C−/− mouse T cell line (W3), its internalization to the inner leaflet of plasma membranes was negligible at 15 °C. However, ATP11A−/−ATP11C−/− cells internalized the exposed PtdSer at 37 °C, a temperature at which trafficking of intracellular membranes was active. In addition to ATP11A and 11C, W3 cells expressed ATP8A1, 8B2, 8B4, 9A, 9B, and 11B, with ATP8A1 and ATP11B being present at recycling endosomes. Cells deficient in four P4-ATPases (ATP8A1, 11A, 11B, and 11C) (QKO) did not constitutively expose PtdSer on the cell surface but lost the ability to re-establish PtdSer asymmetry within 1 hour, even at 37 °C. The expression of ATP11A or ATP11C conferred QKO cells with the ability to rapidly re-establish PtdSer asymmetry at 15 °C and 37 °C, while cells expressing ATP8A1 or ATP11B required a temperature of 37 °C to achieve this function, and a dynamin inhibitor blocked this process. These results revealed that mammalian cells are equipped with two independent mechanisms to re-establish its asymmetry: the first is a rapid process involving plasma membrane flippases, ATP11A and ATP11C, while the other is mediated by ATP8A1 and ATP11B, which require an endocytosis process.
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Affiliation(s)
- Yugo Miyata
- Department of Medical Chemistry, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Kyoko Yamada
- Laboratory of Biochemistry & Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry & Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.
| | - Katsumori Segawa
- Department of Medical Chemistry, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan; Laboratory of Biochemistry & Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.
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19
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Shin HW, Takatsu H. Regulatory Roles of N- and C-Terminal Cytoplasmic Regions of P4-ATPases. Chem Pharm Bull (Tokyo) 2022; 70:524-532. [DOI: 10.1248/cpb.c22-00042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hye-Won Shin
- Graduate School of Pharmaceutical Sciences, Kyoto University
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