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Structural basis for activation of plasma-membrane Ca 2+-ATPase by calmodulin. Commun Biol 2018; 1:206. [PMID: 30511020 PMCID: PMC6255812 DOI: 10.1038/s42003-018-0203-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 10/26/2018] [Indexed: 01/17/2023] Open
Abstract
Plasma-membrane Ca2+-ATPases expel Ca2+ from the cytoplasm and are key regulators of Ca2+ homeostasis in eukaryotes. They are autoinhibited under low Ca2+ concentrations. Calmodulin (CaM)-binding to a unique regulatory domain releases the autoinhibition and activates the pump. However, the structural basis for this activation, including the overall structure of this calcium pump and its complex with calmodulin, is unknown. We previously determined the high-resolution structure of calmodulin in complex with the regulatory domain of the plasma-membrane Ca2+-ATPase ACA8 and revealed a bimodular mechanism of calcium control in eukaryotes. Here we show that activation of ACA8 by CaM involves large conformational changes. Combining advanced modeling of neutron scattering data acquired from stealth nanodiscs and native mass spectrometry with detailed dissection of binding constants, we present a structural model for the full-length ACA8 Ca2+ pump in its calmodulin-activated state illustrating a displacement of the regulatory domain from the core enzyme. Julius Nitsche et al. demonstrate that binding of two calmodulin molecules displaces the regulatory domain of the plasma-membrane Ca2+-ATPase ACA8 to fully activate this Ca2+ pump by relieving the autoinhibition. This work provides structural evidence for the previously proposed bimodular activation mechanism.
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Saffioti NA, de Sautu M, Ferreira-Gomes MS, Rossi RC, Berlin J, Rossi JPFC, Mangialavori IC. E2P-like states of plasma membrane Ca 2+‑ATPase characterization of vanadate and fluoride-stabilized phosphoenzyme analogues. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:366-379. [PMID: 30419189 DOI: 10.1016/j.bbamem.2018.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/22/2018] [Accepted: 11/01/2018] [Indexed: 01/18/2023]
Abstract
The plasma membrane Ca2+‑ATPase (PMCA) belongs to the family of P-type ATPases, which share the formation of an acid-stable phosphorylated intermediate as part of their reaction cycle. The crystal structure of PMCA is currently lacking. Its abundance is approximately 0.1% of the total protein in the membrane, hampering efforts to produce suitable crystals for X-ray structure analysis. In this work we characterized the effect of beryllium fluoride (BeFx), aluminium fluoride (AlFx) and magnesium fluoride (MgFx) on PMCA. These compounds are known inhibitors of P-type ATPases that stabilize E2P ground, E2·P phosphoryl transition and E2·Pi product states. Our results show that the phosphate analogues BeFx, AlFx and MgFx inhibit PMCA Ca2+‑ATPase activity, phosphatase activity and phosphorylation with high apparent affinity. Ca2+‑ATPase inhibition by AlFx and BeFx depended on Mg2+ concentration indicating that this ion stabilizes the complex between these inhibitors and the enzyme. Low pH increases AlFx and BeFx but not MgFx apparent affinity. Eosin fluorescent probe binds with high affinity to the nucleotide binding site of PMCA. The fluorescence of eosin decreases when fluoride complexes bind to PMCA indicating that the environment of the nucleotide binding site is less hydrophobic in E2P-like states. Finally, measuring the time course of E → E2P-like conformational change, we proposed a kinetic model for the binding of fluoride complexes and vanadate to PMCA. In summary, our results show that these fluoride complexes reveal different states of phosphorylated intermediates belonging to the mechanism of hydrolysis of ATP by the PMCA.
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Affiliation(s)
- Nicolás A Saffioti
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Junín 956, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina
| | - Marilina de Sautu
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Junín 956, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina
| | - Mariela S Ferreira-Gomes
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Junín 956, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina
| | - Rolando C Rossi
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Junín 956, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina
| | - Joshua Berlin
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Juan Pablo F C Rossi
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Junín 956, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina
| | - Irene C Mangialavori
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Junín 956, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina.
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Aluminum inhibits the plasma membrane and sarcoplasmic reticulum Ca 2+-ATPases by different mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1580-1588. [PMID: 29859139 DOI: 10.1016/j.bbamem.2018.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/28/2018] [Accepted: 05/25/2018] [Indexed: 11/21/2022]
Abstract
Aluminum (Al3+) is involved in the pathophysiology of neurodegenerative disorders. The mechanisms that have been proposed to explain the action of Al3+ toxicity are linked to changes in the cellular calcium homeostasis, placing the transporting calcium pumps as potential targets. The aim of this work was to study the molecular inhibitory mechanism of Al3+ on Ca2+-ATPases such as the plasma membrane and the sarcoplasmic reticulum calcium pumps (PMCA and SERCA, respectively). These P-ATPases transport Ca2+ actively from the cytoplasm towards the extracellular medium and to the sarcoplasmic reticulum, respectively. For this purpose, we performed enzymatic measurements of the effect of Al3+ on purified preparations of PMCA and SERCA. Our results show that Al3+ is an irreversible inhibitor of PMCA and a slowly-reversible inhibitor of SERCA. The binding of Al3+ is affected by Ca2+ in SERCA, though not in PMCA. Al3+ prevents the phosphorylation of SERCA and, conversely, the dephosphorylation of PMCA. The dephosphorylation time courses of the complex formed by PMCA and Al3+ (EPAl) in the presence of ADP or ATP show that EPAl is composed mainly by the conformer E2P. This work shows for the first time a distinct mechanism of Al3+ inhibition that involves different intermediates of the reaction cycle of these two Ca2+-ATPases.
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Regulation of the Plasma Membrane Calcium ATPases by the actin cytoskeleton. Biochem Biophys Res Commun 2017; 506:347-354. [PMID: 29180009 DOI: 10.1016/j.bbrc.2017.11.151] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 11/22/2017] [Indexed: 01/08/2023]
Abstract
Associations between the cortical cytoskeleton and the components of the plasma membrane are no longer considered to be merely of structural and mechanical nature but are nowadays recognized as dynamic interactions that modulate a plethora of cellular responses. Reorganization of actin filaments upon diverse stimuli - among which is the rise in cytosolic Ca2+ - is involved in cell motility and adhesion, phagocytosis, cytokinesis, and secretion. Actin dynamics also participates in the regulation of ion transport across the membranes where it not only plays a key role in the delivery and stabilization of channels and transporters in the plasma membrane but also in the regulation of their activity. The recently described functional interaction between actin and the Plasma Membrane Ca2+-ATPase (PMCA) represents a novel regulatory mechanism of the pump at the time that unveils a new pathway by which the cortical actin cytoskeleton participates in the regulation of cytosolic Ca2+ homeostasis. In this review, we summarize the current knowledge on the interaction between the cortical actin cytoskeleton and the PMCA and discuss the possible mechanisms that may explain the pump's modulation.
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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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Lopreiato R, Giacomello M, Carafoli E. The plasma membrane calcium pump: new ways to look at an old enzyme. J Biol Chem 2014; 289:10261-10268. [PMID: 24570005 DOI: 10.1074/jbc.o114.555565] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The three-dimensional structure of the PMCA pump has not been solved, but its basic mechanistic properties are known to repeat those of the other Ca(2+) pumps. However, the pump also has unique properties. They concern essentially its numerous regulatory mechanisms, the most important of which is the autoinhibition by its C-terminal tail. Other regulatory mechanisms involve protein kinases and the phospholipids of the membrane in which the pump is embedded. Permanent activation of the pump, e.g. by calmodulin, is physiologically as harmful to cells as its absence. The concept is now emerging that the global control of cell Ca(2+) may not be the main function of the pump; in some cell types, it could even be irrelevant. The main pump role would be the regulation of Ca(2+) in cell microdomains in which the pump co-segregates with partners that modulate the Ca(2+) message and transduce it to important cell functions.
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Affiliation(s)
| | - Marta Giacomello
- Venetian Institute of Molecular Medicine, University of Padova, 35129 Padova, Italy
| | - Ernesto Carafoli
- Venetian Institute of Molecular Medicine, University of Padova, 35129 Padova, Italy.
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Mangialavori IC, Ferreira-Gomes MS, Saffioti NA, González-Lebrero RM, Rossi RC, Rossi JPFC. Conformational changes produced by ATP binding to the plasma membrane calcium pump. J Biol Chem 2013; 288:31030-41. [PMID: 24025327 DOI: 10.1074/jbc.m113.494633] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The aim of this work was to study the plasma membrane calcium pump (PMCA) reaction cycle by characterizing conformational changes associated with calcium, ATP, and vanadate binding to purified PMCA. This was accomplished by studying the exposure of PMCA to surrounding phospholipids by measuring the incorporation of the photoactivatable phosphatidylcholine analog 1-O-hexadecanoyl-2-O-[9-[[[2-[(125)I]iodo-4-(trifluoromethyl-3H-diazirin-3-yl)benzyl]oxy]carbonyl]nonanoyl]-sn-glycero-3-phosphocholine to the protein. ATP could bind to the different vanadate-bound states of the enzyme either in the presence or in the absence of Ca(2+) with high apparent affinity. Conformational movements of the ATP binding domain were determined using the fluorescent analog 2'(3')-O-(2,4,6-trinitrophenyl)adenosine 5'-triphosphate. To assess the conformational behavior of the Ca(2+) binding domain, we also studied the occlusion of Ca(2+), both in the presence and in the absence of ATP and with or without vanadate. Results show the existence of occluded species in the presence of vanadate and/or ATP. This allowed the development of a model that describes the transport of Ca(2+) and its relation with ATP hydrolysis. This is the first approach that uses a conformational study to describe the PMCA P-type ATPase reaction cycle, adding important features to the classical E1-E2 model devised using kinetics methodology only.
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Affiliation(s)
- Irene C Mangialavori
- From the 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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Xia Y, Peng L. Photoactivatable Lipid Probes for Studying Biomembranes by Photoaffinity Labeling. Chem Rev 2013; 113:7880-929. [DOI: 10.1021/cr300419p] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yi Xia
- Aix-Marseille Université, Centre Interdisciplinaire de Nanoscience de Marseille, CNRS UMR 7325, Campus de Luminy, 13288 Marseille, France
| | - Ling Peng
- Aix-Marseille Université, Centre Interdisciplinaire de Nanoscience de Marseille, CNRS UMR 7325, Campus de Luminy, 13288 Marseille, France
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Dalghi MG, Fernández MM, Ferreira-Gomes M, Mangialavori IC, Malchiodi EL, Strehler EE, Rossi JPFC. Plasma membrane calcium ATPase activity is regulated by actin oligomers through direct interaction. J Biol Chem 2013; 288:23380-93. [PMID: 23803603 PMCID: PMC3743507 DOI: 10.1074/jbc.m113.470542] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/19/2013] [Indexed: 02/05/2023] Open
Abstract
As recently described by our group, plasma membrane calcium ATPase (PMCA) activity can be regulated by the actin cytoskeleton. In this study, we characterize the interaction of purified G-actin with isolated PMCA and examine the effect of G-actin during the first polymerization steps. As measured by surface plasmon resonance, G-actin directly interacts with PMCA with an apparent 1:1 stoichiometry in the presence of Ca(2+) with an apparent affinity in the micromolar range. As assessed by the photoactivatable probe 1-O-hexadecanoyl-2-O-[9-[[[2-[(125)I]iodo-4-(trifluoromethyl-3H-diazirin-3-yl)benzyl]oxy]carbonyl]nonanoyl]-sn-glycero-3-phosphocholine, the association of PMCA to actin produced a shift in the distribution of the conformers of the pump toward a calmodulin-activated conformation. G-actin stimulates Ca(2+)-ATPase activity of the enzyme when incubated under polymerizing conditions, displaying a cooperative behavior. The increase in the Ca(2+)-ATPase activity was related to an increase in the apparent affinity for Ca(2+) and an increase in the phosphoenzyme levels at steady state. Although surface plasmon resonance experiments revealed only one binding site for G-actin, results clearly indicate that more than one molecule of G-actin was needed for a regulatory effect on the pump. Polymerization studies showed that the experimental conditions are compatible with the presence of actin in the first stages of assembly. Altogether, these observations suggest that the stimulatory effect is exerted by short oligomers of actin. The functional interaction between actin oligomers and PMCA represents a novel regulatory pathway by which the cortical actin cytoskeleton participates in the regulation of cytosolic Ca(2+) homeostasis.
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Affiliation(s)
| | - Marisa M. Fernández
- Instituto de Estudios de la Immunidad Humoral-Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
| | | | | | - Emilio L. Malchiodi
- Instituto de Estudios de la Immunidad Humoral-Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956 (1113) Buenos Aires, Argentina and
| | - Emanuel E. Strehler
- the Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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