1
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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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2
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Kowalski A, Betzer C, Larsen ST, Gregersen E, Newcombe EA, Bermejo MC, Bendtsen VW, Diemer J, Ernstsen CV, Jain S, Bou AE, Langkilde AE, Nejsum LN, Klipp E, Edwards R, Kragelund BB, Jensen PH, Nissen P. Monomeric α-synuclein activates the plasma membrane calcium pump. EMBO J 2023; 42:e111122. [PMID: 37916890 PMCID: PMC10690453 DOI: 10.15252/embj.2022111122] [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: 03/14/2022] [Revised: 09/19/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023] Open
Abstract
Alpha-synuclein (aSN) is a membrane-associated and intrinsically disordered protein, well known for pathological aggregation in neurodegeneration. However, the physiological function of aSN is disputed. Pull-down experiments have pointed to plasma membrane Ca2+ -ATPase (PMCA) as a potential interaction partner. From proximity ligation assays, we find that aSN and PMCA colocalize at neuronal synapses, and we show that calcium expulsion is activated by aSN and PMCA. We further show that soluble, monomeric aSN activates PMCA at par with calmodulin, but independent of the autoinhibitory domain of PMCA, and highly dependent on acidic phospholipids and membrane-anchoring properties of aSN. On PMCA, the key site is mapped to the acidic lipid-binding site, located within a disordered PMCA-specific loop connecting the cytosolic A domain and transmembrane segment 3. Our studies point toward a novel physiological role of monomeric aSN as a stimulator of calcium clearance in neurons through activation of PMCA.
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Affiliation(s)
- Antoni Kowalski
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- REPIN and Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
- Department of Molecular NeurochemistryMedical University of LodzLodzPoland
- Present address:
ImmunAware ApSHørsholmDenmark
| | - Cristine Betzer
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
- Present address:
Region Midtjylland, Regionshospitalet GødstrupHerningDenmark
| | - Sigrid Thirup Larsen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
| | - Emil Gregersen
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
- Present address:
Department of Clinical MedicineAarhus UniversityAarhus NDenmark
| | - Estella A Newcombe
- REPIN and Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Montaña Caballero Bermejo
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department Biochemistry and Molecular Biology and Genetics, IBMPUniversity of ExtremaduraBadajozSpain
| | - Viktor Wisniewski Bendtsen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
| | - Jorin Diemer
- Theoretical BiophysicsHumboldt‐Universität zu BerlinBerlinGermany
| | | | - Shweta Jain
- Departments of Neurology and PhysiologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Alicia Espiña Bou
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
| | | | - Lene N Nejsum
- Department of Clinical MedicineAarhus UniversityAarhus NDenmark
| | - Edda Klipp
- Theoretical BiophysicsHumboldt‐Universität zu BerlinBerlinGermany
| | - Robert Edwards
- Departments of Neurology and PhysiologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Birthe B Kragelund
- REPIN and Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Poul Henning Jensen
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | - Poul Nissen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
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3
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Corradi GR, Mazzitelli LR, Petrovich GD, de Tezanos Pinto F, Rochi L, Adamo HP. Plasma Membrane Ca 2+ Pump PMCA4z Is More Active Than Splicing Variant PMCA4x. Front Cell Neurosci 2021; 15:668371. [PMID: 34512262 PMCID: PMC8428515 DOI: 10.3389/fncel.2021.668371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
The plasma membrane Ca2+ pumps (PMCA) are P-ATPases that control Ca2+ signaling and homeostasis by transporting Ca2+ out of the eukaryotic cell. Humans have four genes that code for PMCA isoforms (PMCA1-4). A large diversity of PMCA isoforms is generated by alternative mRNA splicing at sites A and C. The different PMCA isoforms are expressed in a cell-type and developmental-specific manner and exhibit differential sensitivity to a great number of regulatory mechanisms. PMCA4 has two A splice variants, the forms "x" and "z". While PMCA4x is ubiquitously expressed and relatively well-studied, PMCA4z is less characterized and its expression is restricted to some tissues such as the brain and heart muscle. PMCA4z lacks a stretch of 12 amino acids in the so-called A-M3 linker, a conformation-sensitive region of the molecule connecting the actuator domain (A) with the third transmembrane segment (M3). We expressed in yeast PMCA4 variants "x" and "z", maintaining constant the most frequent splice variant "b" at the C-terminal end, and obtained purified preparations of both proteins. In the basal autoinhibited state, PMCA4zb showed a higher ATPase activity and a higher apparent Ca2+ affinity than PMCA4xb. Both isoforms were stimulated by calmodulin but PMCA4zb was more strongly activated by acidic lipids than PMCA4xb. The results indicate that a PMCA4 intrinsically more active and more responsive to acidic lipids is produced by the variant "z" of the splicing site A.
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Affiliation(s)
- Gerardo R Corradi
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Luciana R Mazzitelli
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Guido D Petrovich
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Felicitas de Tezanos Pinto
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lucia Rochi
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Hugo P Adamo
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
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4
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Pignataro MF, Dodes-Traian MM, González-Flecha FL, Sica M, Mangialavori IC, Rossi JPFC. Modulation of plasma membrane Ca2+-ATPase by neutral phospholipids: effect of the micelle-vesicle transition and the bilayer thickness. J Biol Chem 2015; 290:6179-90. [PMID: 25605721 PMCID: PMC4358257 DOI: 10.1074/jbc.m114.585828] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 10/29/2014] [Indexed: 11/06/2022] Open
Abstract
The effects of lipids on membrane proteins are likely to be complex and unique for each membrane protein. Here we studied different detergent/phosphatidylcholine reconstitution media and tested their effects on plasma membrane Ca(2+) pump (PMCA). We found that Ca(2+)-ATPase activity shows a biphasic behavior with respect to the detergent/phosphatidylcholine ratio. Moreover, the maximal Ca(2+)-ATPase activity largely depends on the length and the unsaturation degree of the hydrocarbon chain. Using static light scattering and fluorescence correlation spectroscopy, we monitored the changes in hydrodynamic radius of detergent/phosphatidylcholine particles during the micelle-vesicle transition. We found that, when PMCA is reconstituted in mixed micelles, neutral phospholipids increase the enzyme turnover. The biophysical changes associated with the transition from mixed micelles to bicelles increase the time of residence of the phosphorylated intermediate (EP), decreasing the enzyme turnover. Molecular dynamics simulations analysis of the interactions between PMCA and the phospholipid bilayer in which it is embedded show that in the 1,2-dioleoyl-sn-glycero-3-phosphocholine bilayer, charged residues of the protein are trapped in the hydrophobic core. Conversely, in the 1,2-dimyristoyl-sn-glycero-3-phosphocholine bilayer, the overall hydrophobic-hydrophilic requirements of the protein surface are fulfilled the best, reducing the thermodynamic cost of exposing charged residues to the hydrophobic core. The apparent mismatch produced by a 1,2-dioleoyl-sn-glycero-3-phosphocholine thicker bilayer could be a structural foundation to explain its functional effect on PMCA.
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Affiliation(s)
- María Florencia Pignataro
- From the Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
| | - Martín M Dodes-Traian
- From the Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
| | - F Luis González-Flecha
- From the Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
| | - Mauricio Sica
- the Laboratorio de Bioenergías, IEDS, CONICET Centro Atómico Bariloche, E. Bustillo 9,500 (8400), San Carlos de Bariloche, Río Negro, Argentina
| | - Irene C Mangialavori
- From the Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
| | - Juan Pablo F C Rossi
- From the Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
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5
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Penniston JT, Padányi R, Pászty K, Varga K, Hegedus L, Enyedi A. Apart from its known function, the plasma membrane Ca²⁺ATPase can regulate Ca²⁺ signaling by controlling phosphatidylinositol 4,5-bisphosphate levels. J Cell Sci 2013; 127:72-84. [PMID: 24198396 DOI: 10.1242/jcs.132548] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasma membrane Ca(2+) ATPases (PMCAs, also known as ATP2B1-ATP2B4) are known targets of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P₂], but if and how they control the PtdIns(4,5)P₂ pool has not been considered. We demonstrate here that PMCAs protect PtdIns(4,5)P₂ in the plasma membrane from hydrolysis by phospholipase C (PLC). Comparison of active and inactive PMCAs indicates that the protection operates by two mechanisms; one requiring active PMCAs, the other not. It appears that the mechanism requiring activity is the removal of the Ca(2+) required for sustained PLC activity, whereas the mechanism not requiring activity is PtdIns(4,5)P₂ binding. We show that in PMCA overexpressing cells, PtdIns(4,5)P₂ binding can lead to less inositol 1,4,5-triphosphate (InsP₃) and diminished Ca(2+) release from intracellular Ca(2+) pools. Inspection of a homology model of PMCA suggests that PMCAs have a conserved cluster of basic residues forming a 'blue collar' at the interface between the membrane core and the cytoplasmic domains. By molecular dynamics simulation, we found that the blue collar forms four binding pockets for the phosphorylated inositol head group of PtdIns(4,5)P₂; these pockets bind PtdIns(4,5)P₂ strongly and frequently. Our studies suggest that by having the ability to bind PtdIns(4,5)P₂, PMCAs can control the accessibility of PtdIns(4,5)P₂ for PLC and other PtdIns(4,5)P₂-mediated processes.
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Affiliation(s)
- John T Penniston
- Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1025 Budapest, Hungary
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6
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Autoinhibition mechanism of the plasma membrane calcium pump isoforms 2 and 4 studied through lipid-protein interaction. Biochem J 2012; 443:125-31. [PMID: 22214540 DOI: 10.1042/bj20111035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The autoinhibition/activation of the PMCA (plasma membrane Ca2+-ATPase) involves conformational changes in the membrane region of the protein that affect the amount of lipids directly associated with the transmembrane domain. The lipid-protein-dependence of PMCA isoforms 2 and 4 expressed and obtained in purified form from Saccharomyces cerevisiae was investigated using the phosphatidylcholine analogue [125I]TID-PC/16 {l-O-hexadecanoyl-2-O-[9-[[[2-[125I]iodo-4-(trifluoromemyl-3H-diazirin-3-yl)benzyl]oxy]carbonyl]nonanoyl]-sn-glycero-3-phosphocholine}, which was incorporated into mixtures of dimyristoylphosphatidylcholine and the non-ionic detergent C12E10 [deca(ethylene glycol) dodecyl ether]. We found no differences between the recombinant PMCA4 and PMCA purified from erythrocytes (ePMCA). However, titration of the half-maximal activation by Ca2+/calmodulin of PMCA2 showed 30-fold higher affinity than PMCA4. PMCA2 exhibited a lower level of labelling in the autoinhibited conformation relative to PMCA4, indicating that the lower autoinhibition was correlated with a lower exposure to lipids in the autoinhibited state. Analysis of the lipid-protein stoichiometry showed that the lipid annulus of PMCA varies: (i) in accordance to the conformational state of the enzyme; and (ii) depending on the different isoforms of PMCA. PMCA2 during Ca2+ transport changes its conformation to a lesser extent than PMCA4, an isoform more sensitive to modulation by calmodulin and acidic phospholipids. This is the first demonstration of a dynamic behaviour of annular lipids and PMCA.
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7
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de Tezanos Pinto F, Corradi GR, de la Hera DP, Adamo HP. CHO cells expressing the human P5-ATPase ATP13A2 are more sensitive to the toxic effects of herbicide Paraquat. Neurochem Int 2012; 60:243-8. [DOI: 10.1016/j.neuint.2012.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 12/30/2011] [Accepted: 01/03/2012] [Indexed: 11/15/2022]
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8
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Mangialavori I, Villamil-Giraldo AM, Pignataro MF, Ferreira-Gomes M, Caride AJ, Rossi JPFC. Plasma membrane calcium pump (PMCA) differential exposure of hydrophobic domains after calmodulin and phosphatidic acid activation. J Biol Chem 2011; 286:18397-404. [PMID: 21454645 DOI: 10.1074/jbc.m110.210088] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The exposure of the plasma membrane calcium pump (PMCA) to the surrounding phospholipids was assessed by measuring the incorporation of the photoactivatable phosphatidylcholine analog [(125)I]TID-PC/16 to the protein. In the presence of Ca(2+) both calmodulin (CaM) and phosphatidic acid (PA) greatly decreased the incorporation of [(125)I]TID-PC/16 to PMCA. Proteolysis of PMCA with V8 protease results in three main fragments: N, which includes transmembrane segments M1 and M2; M, which includes M3 and M4; and C, which includes M5 to M10. CaM decreased the level of incorporation of [(125)I]TID-PC/16 to fragments M and C, whereas phosphatidic acid decreased the incorporation of [(125)I]TID-PC/16 to fragments N and M. This suggests that the conformational changes induced by binding of CaM or PA extend to the adjacent transmembrane domains. Interestingly, this result also denotes differences between the active conformations produced by CaM and PA. To verify this point, we measured resonance energy transfer between PMCA labeled with eosin isothiocyanate at the ATP-binding site and the phospholipid RhoPE included in PMCA micelles. CaM decreased the efficiency of the energy transfer between these two probes, whereas PA did not. This result indicates that activation by CaM increases the distance between the ATP-binding site and the membrane, but PA does not affect this distance. Our results disclose main differences between PMCA conformations induced by CaM or PA and show that those differences involve transmembrane regions.
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Affiliation(s)
- Irene Mangialavori
- Instituto de Química y Fisicoquímica Biologicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Junín 956, 1113 Buenos Aires, Argentina
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9
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Borchman D, Yappert MC. Lipids and the ocular lens. J Lipid Res 2010; 51:2473-88. [PMID: 20407021 PMCID: PMC2918433 DOI: 10.1194/jlr.r004119] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 01/29/2010] [Indexed: 11/20/2022] Open
Abstract
The unusually high levels of saturation and thus order contribute to the uniqueness of human lens membranes. In addition, and unlike in most biomembranes, most of the lens lipids are associated with proteins, thus reducing their mobility. The major phospholipid of the human lens is dihydrosphingomyelin. Found in significant quantities only in primate lenses, particularly human ones, this lipid is so extremely stable that it was reported to be the only lipid remaining in a frozen mammoth 40,000 years after its death. Unusually high levels of cholesterol add peculiarity to the composition of lens membranes. Beyond the lateral segregation of lipids into dynamic domains known as rafts, the high abundance of cholesterol in the human lens leads to the formation of patches of pure cholesterol. Changes in human lens lipid composition with age and disease as well as differences among species are greater than those observed for any other biomembrane. The relationships among lens membrane composition, structure, and lipid conformation reviewed in this article are unique to the mammalian lens and offer exciting insights into lens membrane function. This review focuses on findings reported over the last two decades that demonstrate the uniqueness of mammalian lens membranes regarding their morphology and composition. Because the membranes of human lenses do undergo the most dramatic changes with age and cataractogenesis, the final sections of this review address our current knowledge of the unusual composition and organization of adult human lens membranes with and without opacification. Finally, the questions that still remain to be answered are presented.
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Affiliation(s)
- Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA.
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10
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Brini M, Di Leva F, Ortega CK, Domi T, Ottolini D, Leonardi E, Tosatto SCE, Carafoli E. Deletions and mutations in the acidic lipid-binding region of the plasma membrane Ca2+ pump: a study on different splicing variants of isoform 2. J Biol Chem 2010; 285:30779-91. [PMID: 20643655 DOI: 10.1074/jbc.m110.140475] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acidic phospholipids increase the affinity of the plasma membrane Ca(2+)-ATPase pump for Ca(2+). They interact with the C-terminal region of the pump and with a domain in the loop connecting transmembrane domains 2 and 3 (A(L) region) next to site A of alternative splicing. The contribution of the two phospholipid-binding sites and the possible interference of splicing inserts at site A with the regulation of the ATPase activity of isoform 2 of the pump by phospholipids have been analyzed. The activity of the full-length z/b variant (no insert at site A), the w/b (with insert at site A), and the w/a variant, containing both the 45-amino acid A-site insert and a C-site insert that truncates the pump in the calmodulin binding domain, has been analyzed in microsomal membranes of overexpressing CHO cells. The A-site insertion did not modify the phospholipid sensitivity of the pump, but the doubly inserted w/a variant became insensitive to acidic phospholipids, even if containing the intact A(L) phospholipid binding domain. Pump mutants in which 12 amino acids had been deleted, or single lysine mutations introduced, in the A(L) region were studied by monitoring agonist-induced Ca(2+) transients in overexpressing CHO cells. The 12-residue deletion completely abolished the ATPase activity of the w/a variant but only reduced that of the z/b variant, which was also affected by the single lysine substitutions in the same domain. A structural interpretation of the interplay of the pump with phospholipids, and of the mechanism of their activation, is proposed on the basis of molecular modeling studies.
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Affiliation(s)
- Marisa Brini
- Department of Biological Chemistry, University of Padova, 35131 Padova, Italy.
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11
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Xiong Y, Antalffy G, Enyedi Á, Strehler EE. Apical localization of PMCA2w/b is lipid raft-dependent. Biochem Biophys Res Commun 2009; 384:32-6. [PMID: 19379709 PMCID: PMC2731683 DOI: 10.1016/j.bbrc.2009.04.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 04/11/2009] [Indexed: 01/20/2023]
Abstract
Alternative splicing of the first intracellular loop differentially targets plasma membrane calcium ATPase (PMCA) isoform 2 to the apical or basolateral membrane in MDCK cells. To determine if the targeting is affected by lipid interactions, we stably expressed PMCA2w/b and PMCA2z/b in MDCK cells, and analyzed the PMCA distribution by confocal fluorescence microscopy and membrane fractionation. PMCA2w/b showed clear apical and lateral distribution, whereas PMCA2z/b was mainly localized to the basolateral membrane. A significant fraction of PMCA2w/b partitioned into low-density membranes associated with lipid rafts. Depletion of membrane cholesterol by methyl-beta-cyclodextrin resulted in reduced lipid raft association and a striking loss of PMCA2w/b from the apical membrane, whereas the lateral localization of PMCA2z/b remained unchanged. Our data indicate that alternative splicing differentially affects the lipid interactions of PMCA2w/b and PMCA2z/b and that the apical localization of PMCA2w/b is lipid raft-dependent and sensitive to cholesterol depletion.
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Affiliation(s)
- Yuning Xiong
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Géza Antalffy
- National Blood Center, Department of Molecular Cell Biology, H-1113 Budapest, Hungary
| | - Ágnes Enyedi
- National Blood Center, Department of Molecular Cell Biology, H-1113 Budapest, Hungary
| | - Emanuel E. Strehler
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN, USA
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12
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Meneghelli S, Fusca T, Luoni L, De Michelis MI. Dual mechanism of activation of plant plasma membrane Ca2+-ATPase by acidic phospholipids: evidence for a phospholipid binding site which overlaps the calmodulin-binding site. Mol Membr Biol 2009; 25:539-46. [PMID: 18988067 DOI: 10.1080/09687680802508747] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The effect of phospholipids on the activity of isoform ACA8 of Arabidopsis thaliana plasma membrane (PM) Ca2+-ATPase was evaluated in membranes isolated from Saccharomyces cerevisiae strain K616 expressing wild type or mutated ACA8 cDNA. Acidic phospholipids stimulated the basal Ca2+-ATPase activity in the following order of efficiency: phosphatidylinositol 4-monophosphate > phosphatidylserine > phosphatidylcholine approximately = phosphatidylethanolamine approximately = 0. Acidic phospholipids increased V(max-Ca2+) and lowered the value of K(0.5-Ca2+) below the value measured in the presence of calmodulin (CaM). In the presence of CaM acidic phospholipids activated ACA8 by further decreasing its K(0.5-Ca2+) value. Phosphatidylinositol 4-monophosphate and, with lower efficiency, phosphatidylserine bound peptides reproducing ACA8 N-terminus (aa 1-116). Single point mutation of three residues (A56, R59 and Y62) within the sequence A56-T63 lowered the apparent affinity of ACA8 for phosphatidylinositol 4-monophosphate by two to three fold, indicating that this region contains a binding site for acidic phospholipids. However, the N-deleted mutant Delta74-ACA8 was also activated by acidic phospholipids, indicating that acidic phospholipids activate ACA8 through a complex mechanism, involving interaction with different sites. The striking similarity between the response to acidic phospholipids of ACA8 and animal plasma membrane Ca2+-ATPase provides new evidence that type 2B Ca2+-ATPases share common regulatory properties independently of structural differences such as the localization of the terminal regulatory region at the N- or C-terminal end of the protein.
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Affiliation(s)
- Silvia Meneghelli
- Dipartimento di Biologia, Universita di Milano, Istituto di Biofisica del CNR, Sezione di Milano, Milano, Italy
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Di Leva F, Domi T, Fedrizzi L, Lim D, Carafoli E. The plasma membrane Ca2+ ATPase of animal cells: structure, function and regulation. Arch Biochem Biophys 2008; 476:65-74. [PMID: 18328800 DOI: 10.1016/j.abb.2008.02.026] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 02/15/2008] [Accepted: 02/17/2008] [Indexed: 12/19/2022]
Abstract
Most important processes in cell life are regulated by calcium (Ca2+). A number of mechanisms have thus been developed to maintain the concentration of free Ca2+ inside cells at the level (100-200nM) necessary for the optimal operation of the targets of its regulatory function. The systems that move Ca2+ back and forth across membranes are important actors in its control. The plasma membrane calcium ATPase (PMCA pump) which ejects Ca2+ from all eukaryotic cell types will be the topic of this contribution. The pump uses a molecule of ATP to transport one molecule of Ca2+ from the cytosol to the external environment. It is a P-type ATPase encoded by four genes (ATP2B1-4), the transcripts of which undergo different types of alternative splicing. Many pump variants thus exist. Their multiplicity is best explained by the specific Ca2+ demands in different cell types. In keeping with these demands, the isoforms are differently expressed in tissues and cell types and have differential Ca2+ extruding properties. At very low Ca2+ concentrations the PMCAs are nearly inactive. They must be activated by calmodulin, by acid phospholipids, by protein kinases, and by other means, e.g., a dimerization process. Other proteins interact with the PMCAs (i.e., MAGUK and NHERF at the PDZ domain and calcineurin A in the main intracellular domain) to sort them to specific regions of the cell membrane or to regulate their function. In some cases the interaction is isoform, or even splice variant specific. PMCAs knock out (KO) mice have been generated and have contributed information on the importance of PMCAs to cells and organisms. So far, only one human genetic disease, hearing loss, has been traced back to a PMCA defect.
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Affiliation(s)
- Francesca Di Leva
- Department of Biochemistry, University of Padova, Viale G. Colombo, 3 35131 Padova, Italy
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Gatto C, Helms JB, Prasse MC, Huang SY, Zou X, Arnett KL, Milanick MA. Similarities and differences between organic cation inhibition of the Na,K-ATPase and PMCA. Biochemistry 2006; 45:13331-45. [PMID: 17073454 DOI: 10.1021/bi060667j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of three classes of organic cations on the inhibition of the plasma membrane Ca pump (PMCA) were determined and compared to inhibition of the Na pump. Quaternary amines (tetramethylammonium, tetraethylammonium, and tetrapropylammonium, TMA, TEA, and TPA, respectively) did not inhibit PMCA. This is not to imply that PMCA is inherently selective against monovalent cations because guanidine and tetramethylguanidine inhibited PMCA by competing with Ca(2+). The divalent organic cation, ethyl diamine, inhibited PMCA but was not competitive with Ca(2+). In contrast, propyl diamine did compete with Ca(2+) and was about 10-fold more potent than butyl diamine in inhibiting PMCA. For the Na pump, both TEA and TPA inhibited, but TMA did not. TEA, guanidine, and tetramethylguanidine inhibition was competitive with Na(+) for ATPase activation and with K(+) for pNPPase activation, both of which are cytoplasmic substrate cation effects. Thus, these findings are consistent with TEA, guanidine, and tetramethylguanidine inhibiting from the cytoplasmic side of the Na pump; in contrast, we have previously shown that TPA did not inhibit from the cytoplasmic side. The divalent alkane diamines ethyl, propyl, and butyl diamine all inhibited the Na pump and all competed at the intracellular surface. The order of potency was ED > PD > BD consistent with an optimal size for binding; similarly, for the quaternary amines TMA is apparently too small to make appropriate contacts, and TPA is too large. Homology models based upon the high-resolution SERCA structure are included to contextualize the kinetic observations.
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Affiliation(s)
- Craig Gatto
- Division of Biomedical Sciences, Department of Biological Sciences, Illinois State University, Normal, Illinois 61790-4120, USA
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de Tezanos Pinto F, Adamo HP. Deletions in the ALregion of the h4xb plasma membrane Ca2+pump. FEBS Lett 2006; 580:1576-80. [PMID: 16488415 DOI: 10.1016/j.febslet.2006.01.088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 01/26/2006] [Accepted: 01/27/2006] [Indexed: 11/21/2022]
Abstract
Mutants of the plasma membrane Ca(2+) pump (human isoform 4xb) with deletions in the linker between domain A and transmembrane segment M3 (A(L) region) were constructed and expressed in Chinese hamster ovary cells. The total or partial removal of the amino acid segment 300-349 did not change the maximal Ca(2+) transport activity, but mutants with deletions involving residues 300-338 exhibited a higher apparent affinity for Ca(2+) than the wild type h4xb enzyme. Deletion of the putative acidic lipid interacting sequence (residues 339-349) had no observable functional consequences. The removal of either residues 300-314 or 313-338 resulted in a similar increase in the apparent Ca(2+) affinity of the pump although the increase was somewhat lower than that obtained by the deletion 300-349 suggesting that both deletions affected the same structural determinant. The results show that alterations in the region of the alternative splicing site A change the sensitivity to Ca(2+) of the human isoform 4 of the PMCA.
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Affiliation(s)
- Felicitas de Tezanos Pinto
- IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires Junín 956, 1113 Buenos Aires, Argentina
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Zhao Y, Zhang X. Heparin inhibits the reconstituted plasma membrane Ca(2+)-ATPase from porcine brain synaptosome. Glycoconj J 2004; 19:373-8. [PMID: 14707483 DOI: 10.1023/b:glyc.0000004008.30509.ff] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Heparin has been shown to be involved in the regulation of cellular Ca(2+) by binding to many proteins with high affinity. Here we examined the effects of heparin on the plasma membrane Ca(2+)-ATPase from porcine brain synaptosome. Our results showed that heparin dramatically inhibited the ATP hydrolysis and Ca(2+) uptake in the presence and absence of calmodulin. Together with controlled proteolysis by trypsin, we concluded that the calmodulin-binding domain of the plasma membrane Ca(2+)-ATPase was less important for the heparin inhibition. Excess phosphatidylserine was able to eliminate the heparin inhibition. We observed that Ca(2+) affinity kept no obvious changes, but the ATP affinity of plasma membrane Ca(2+)-ATPase was apparently decreased in the presence of heparin. Our results indicated that heparin had little effects on ATP or Ca(2+) binding sites of the enzyme.
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Affiliation(s)
- Yongfang Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
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Adamo HP, Pinto FDT, Bredeston LM, Corradi GR. Acidic-lipid responsive regions of the plasma membrane Ca2+ pump. Ann N Y Acad Sci 2003; 986:552-3. [PMID: 12763888 DOI: 10.1111/j.1749-6632.2003.tb07252.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hugo P Adamo
- Instituto de Química y Fisicoquímica Biológicas, Universidad de Buenos Aires, Junín 956 1113, Argentina.
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