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Schachter J, Alvarez CL, Bazzi Z, Faillace MP, Corradi G, Hattab C, Rinaldi DE, Gonzalez-Lebrero R, Molineris MP, Sévigny J, Ostuni MA, Schwarzbaum PJ. Extracellular ATP hydrolysis in Caco-2 human intestinal cell line. Biochim Biophys Acta Biomembr 2021; 1863:183679. [PMID: 34216588 DOI: 10.1016/j.bbamem.2021.183679] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
Extracellular nucleotides and nucleosides activate signaling pathways that play major roles in the physiology and pathophysiology of the gastrointestinal tract. Ectonucleotidases hydrolyze extracellular nucleotides and thus regulate ligand exposure to purinergic receptors. In this study, we investigated the expression, localization and activities of ectonucleotidases using Caco-2 cells, a model of human intestinal epithelial cells. In addition, by studying ATP release and the rates of extracellular ATP (eATP) hydrolysis, we analyzed the contribution of these processes to the regulation of eATP in these cells. Results show that Caco-2 cells regulate the metabolism of eATP and by-products by ecto-nucleoside triphosphate diphosphohydrolase-1 and -2, a neutral ecto-phosphatase and ecto-5'-nucleotidase. All these ectoenzymes were kinetically characterized using intact cells, and their presence confirmed by denatured and native gels, western blot and cytoimmunofluorescence techniques. In addition, regulation of eATP was studied by monitoring the dynamic balance between intracellular ATP release and ectoATPase activity. Following mechanical and hypotonic stimuli, Caco-2 cells triggered a strong but transient release of intracellular ATP, with almost no energy cost, leading to a steep increase of eATP concentration, which was later reduced by ectoATPase activity. A data-driven algorithm allowed quantifying and predicting the rates of ATP release and ATP consumption contributing to the dynamic accumulation of ATP at the cell surface.
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Affiliation(s)
- J Schachter
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina.
| | - C L Alvarez
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina; Universidad de Buenos Aires (UBA), Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956, C1113AAD Buenos Aires, Argentina
| | - Z Bazzi
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina
| | - M P Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay), Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - G Corradi
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina; Universidad de Buenos Aires (UBA), Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956, C1113AAD Buenos Aires, Argentina
| | - C Hattab
- Université de Paris, UMR_S1134, BIGR, Inserm, F-75015 Paris, France; Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France
| | - D E Rinaldi
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina; Universidad de Buenos Aires (UBA), Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956, C1113AAD Buenos Aires, Argentina
| | - R Gonzalez-Lebrero
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina; Universidad de Buenos Aires (UBA), Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956, C1113AAD Buenos Aires, Argentina
| | - M Pucci Molineris
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP) "Prof. Dr. Rodolfo R. Brenner", Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Médicas, Av. 60 y Av. 120, La Plata, Argentina; Universidad Nacional de La Plata, Facultad de Ciencias Médicas, Av. 60 y Av. 120, La Plata, Argentina
| | - J Sévigny
- Centre de Recherche du CHU de Québec-Université Laval, Québec, QC, Canada; Département de Microbiologie-Infectiologie et d'Immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - M A Ostuni
- Université de Paris, UMR_S1134, BIGR, Inserm, F-75015 Paris, France; Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France
| | - P J Schwarzbaum
- Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini", Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina; Universidad de Buenos Aires (UBA), Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956, C1113AAD Buenos Aires, Argentina.
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Rinaldi DE, Ontiveros MQ, Saffioti NA, Vigil MA, Mangialavori IC, Rossi RC, Rossi JP, Espelt MV, Ferreira-Gomes MS. Epigallocatechin 3-gallate inhibits the plasma membrane Ca 2+-ATPase: effects on calcium homeostasis. Heliyon 2021; 7:e06337. [PMID: 33681501 PMCID: PMC7930289 DOI: 10.1016/j.heliyon.2021.e06337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/16/2021] [Accepted: 02/17/2021] [Indexed: 12/27/2022] Open
Abstract
Flavonoids are natural compounds responsible for the health benefits of green tea. Some of the flavonoids present in green tea are catechins, among which are: epigallocatechin, epicatechin-3-gallate, epicatechin, catechin and epigallocatechin-3-gallate (EGCG). The latter was found to induce apoptosis, reduce reactive oxygen species, in some conditions though in others it acts as an oxidizing agent, induce cell cycle arrest, and inhibit carcinogenesis. EGCG also was found to be involved in calcium (Ca2+) homeostasis in excitable and in non-excitable cells. In this study, we investigate the effect of catechins on plasma membrane Ca2+-ATPase (PMCA), which is one of the main mechanisms that extrude Ca2+ out of the cell. Our studies comprised experiments on the isolated PMCA and on cells overexpressing the pump. Among catechins that inhibited PMCA activity, the most potent inhibitor was EGCG. EGCG inhibited PMCA activity in a reversible way favoring E1P conformation. EGCG inhibition also occurred in the presence of calmodulin, the main pump activator. Finally, the effect of EGCG on PMCA activity was studied in human embryonic kidney cells (HEK293T) that transiently overexpress hPMCA4. Results show that EGCG inhibited PMCA activity in HEK293T cells, suggesting that the effects observed on isolated PMCA occur in living cells.
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Affiliation(s)
| | | | - Nicolas A. Saffioti
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
| | - Maximiliano A. Vigil
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
| | - Irene C. Mangialavori
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
| | - Rolando C. Rossi
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
| | - Juan P. Rossi
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
| | - María V. Espelt
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
| | - Mariela S. Ferreira-Gomes
- IQUIFIB – Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Junín 956, 1113 Buenos Aires, Argentina
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Leal Denis MF, Lefevre SD, Alvarez CL, Lauri N, Enrique N, Rinaldi DE, Gonzalez-Lebrero R, Vecchio LE, Espelt MV, Stringa P, Muñoz-Garay C, Milesi V, Ostuni MA, Herlax V, Schwarzbaum PJ. Regulation of extracellular ATP of human erythrocytes treated with α-hemolysin. Effects of cell volume, morphology, rheology and hemolysis. Biochim Biophys Acta Mol Cell Res 2019; 1866:896-915. [PMID: 30726708 DOI: 10.1016/j.bbamcr.2019.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/10/2019] [Accepted: 01/30/2019] [Indexed: 12/17/2022]
Abstract
Alpha-hemolysin (HlyA) of uropathogenic strains of Escherichia coli irreversibly binds to human erythrocytes (RBCs) and triggers activation of ATP release and metabolic changes ultimately leading to hemolysis. We studied the regulation of extracellular ATP (ATPe) of RBCs exposed to HlyA. Luminometry was used to assess ATP release and ATPe hydrolysis, whereas changes in cell volume and morphology were determined by electrical impedance, ektacytometry and aggregometry. Exposure of RBCs to HlyA induced a strong increase of [ATPe] (3-36-fold) and hemolysis (1-44-fold), partially compensated by [ATPe] hydrolysis by ectoATPases and intracellular ATPases released by dead cells. Carbenoxolone, a pannexin 1 inhibitor, partially inhibited ATP release (43-67%). The un-acylated toxin ProHlyA and the deletion analog HlyA∆914-936 were unable to induce ATP release or hemolysis. For HlyA treated RBCs, a data driven mathematical model showed that simultaneous lytic and non-lytic release mainly governed ATPe kinetics, while ATPe hydrolysis became important after prolonged toxin exposure. HlyA induced a 1.5-fold swelling, while blocking this swelling reduced ATP release by 77%. Blocking ATPe activation of purinergic P2X receptors reduced swelling by 60-80%. HlyA-RBCs showed an acute 1.3-2.2-fold increase of Ca2+i, increased crenation and externalization of phosphatidylserine. Perfusion of HlyA-RBCs through adhesion platforms showed strong adhesion to activated HMEC cells, followed by rapid detachment. HlyA exposed RBCs exhibited increased sphericity under osmotic stress, reduced elongation under shear stress, and very low aggregation in viscous media. Overall results showed that HlyA-RBCs displayed activated ATP release, high but weak adhesivity, low deformability and aggregability and high sphericity.
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Affiliation(s)
- M F Leal Denis
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Analítica, Cátedra de Química Química Analítica y Fisicoquímica, Junín 956 Buenos Aires, Argentina
| | - S D Lefevre
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.; Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France
| | - C L Alvarez
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Intendente Güiraldes 2160 Buenos Aires, Argentina
| | - N Lauri
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica. Cátedra de Química Biológica Superior, Junín 956 Buenos Aires, Argentina
| | - N Enrique
- Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Facultad de Ciencias Exactas, Calle 47 y 115 La Plata, Argentina.; Universidad Nacional de la Plata, Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Cátedra de Fisiología, Calle 47, Casco Urbano, La Plata, Argentina
| | - D E Rinaldi
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956 Buenos Aires, Argentina
| | - R Gonzalez-Lebrero
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Cátedra de Química Biológica, Junín 956 Buenos Aires, Argentina
| | - L E Vecchio
- Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Facultad de Ciencias Exactas, Calle 47 y 115 La Plata, Argentina.; Universidad Nacional de la Plata, Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Cátedra de Fisiología, Calle 47, Casco Urbano, La Plata, Argentina
| | - M V Espelt
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica. Cátedra de Química Biológica Superior, Junín 956 Buenos Aires, Argentina
| | - P Stringa
- Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Facultad de Ciencias Exactas, Calle 47 y 115 La Plata, Argentina.; Universidad Favaloro, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Medicina Traslacional, Trasplante y Bioingeniería (IMETTyB), Av. Entre Ríos 495, Buenos Aires, Argentina.; Universidad Nacional de La Plata, Laboratorio de Trasplante de Órganos y Tejidos, Facultad de Ciencias, Calle 60 y 120, La Plata, Argentina
| | - C Muñoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (UNAM), Av. Universidad s/n, Cuernavaca, Mexico
| | - V Milesi
- Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Facultad de Ciencias Exactas, Calle 47 y 115 La Plata, Argentina.; Universidad Nacional de la Plata, Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Cátedra de Fisiología, Calle 47, Casco Urbano, La Plata, Argentina
| | - M A Ostuni
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.; Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France
| | - V Herlax
- Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP) "Prof. Dr. Rodolfo R. Brenner", Facultad de Ciencias Médicas, Av. 60 y Av. 120, La Plata, Argentina.; Universidad Nacional de La Plata, Facultad de Ciencias Médicas, Av. 60 y Av. 120, La Plata, Argentina
| | - P J Schwarzbaum
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Junín 956 Buenos Aires, Argentina.; Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica. Cátedra de Química Biológica Superior, Junín 956 Buenos Aires, Argentina..
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Rinaldi DE, Corradi GR, Cuesta LM, Adamo HP, de Tezanos Pinto F. The Parkinson-associated human P5B-ATPase ATP13A2 protects against the iron-induced cytotoxicity. Biochim Biophys Acta 2015; 1848:1646-55. [PMID: 25912790 DOI: 10.1016/j.bbamem.2015.04.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 03/28/2015] [Accepted: 04/15/2015] [Indexed: 12/11/2022]
Abstract
P-type ion pumps are membrane transporters that have been classified into five subfamilies termed P1-P5. The ion transported by the P5-ATPases is not known. Five genes named ATP13A1-ATP13A5 that belong to the P5-ATPase group are present in humans. Loss-of-function mutations in the ATP13A2 gene (PARK9, OMIM 610513) underlay a form of Parkinson's disease (PD) known as the Kufor-Rakeb syndrome (KRS), which belongs to the group of syndromes of neurodegeneration with brain iron accumulation (NBIA). Here we report that the cytotoxicity induced by iron exposure was two-fold reduced in CHO cells stably expressing the ATP13A2 recombinant protein (ATP13A2). Moreover, the iron content in ATP13A2 cells was lower than control cells stably expressing an inactive mutant of ATP13A2. ATP13A2 expression caused an enlargement of lysosomes and late endosomes. ATP13A2 cells exhibited a reduced iron-induced lysosome membrane permeabilization (LMP). These results suggest that ATP13A2 overexpression improves the lysosome membrane integrity and protects against the iron-induced cell damage.
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Affiliation(s)
- Débora E Rinaldi
- From IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina
| | - Gerardo R Corradi
- From IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina
| | - Lucía Martínez Cuesta
- From IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina
| | - Hugo P Adamo
- From IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina.
| | - Felicitas de Tezanos Pinto
- From IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina.
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Mazzitelli LR, Rinaldi DE, Corradi GR, Adamo HP. The plasma membrane Ca2+ pump catalyzes the hydrolysis of ATP at low rate in the absence of Ca2+. Arch Biochem Biophys 2009; 495:62-6. [PMID: 20035709 DOI: 10.1016/j.abb.2009.12.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 12/16/2009] [Accepted: 12/17/2009] [Indexed: 11/30/2022]
Abstract
The plasma membrane Ca2+ ATPase catalyzed the hydrolysis of ATP in the presence of millimolar concentrations of EGTA and no added Ca2+ at a rate near 1.5% of that attained at saturating concentrations of Ca2+. Like the Ca-dependent ATPase, the Ca-independent activity was lower when the enzyme was autoinhibited, and increased when the enzyme was activated by acidic lipids or partial proteolysis. The ATP concentration dependence of the Ca2+-independent ATPase was consistent with ATP binding to the low affinity modulatory site. In this condition a small amount of hydroxylamine-sensitive phosphoenzyme was formed and rapidly decayed when chased with cold ATP. We propose that the Ca2+-independent ATP hydrolysis reflects the well known phosphatase activity which is maximal in the absence of Ca2+ and is catalyzed by E(2)-like forms of the enzyme. In agreement with this idea pNPP, a classic phosphatase substrate was a very effective inhibitor of the ATP hydrolysis.
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Affiliation(s)
- Luciana R Mazzitelli
- IQUIFIB-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina
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6
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Rinaldi DE, Adamo HP. The role of the Ca2+ binding ligand Asn879 in the function of the plasma membrane Ca2+ pump. Biochim Biophys Acta 2009; 1788:2404-10. [PMID: 19761757 DOI: 10.1016/j.bbamem.2009.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 08/26/2009] [Accepted: 09/06/2009] [Indexed: 11/27/2022]
Abstract
Asn879 in the transmembrane segment M6 of the plasma membrane Ca(2+) pump (PMCA human isoform 4xb) has been proposed to coordinate Ca(2+) at the transport site through its carboxylate. This idea agrees with the fact that this Asn is conserved in other Ca(2+)-ATPases but is replaced by Asp, Glu, and other residues in closely related 2P-type ATPases of different ionic specificity. Previous mutagenesis studies have shown that the substitution of Ala for Asn abolishes the activity of the enzyme (Adebayo et al., 1995; Guerini et al., 1996). We have constructed a mutant PMCA in which the Asn879 was substituted by Asp. The mutant protein was expressed in Saccharomyces cerevisiae, solubilized and purified by calmodulin affinity chromatography. The Asn879Asp PMCA mutant exhibited about 30% of the wild type Ca(2+)-dependent ATPase activity and only a minor reduction of the apparent affinity for Ca(2+). The decrease in the Ca(2+)-ATPase of the mutant enzyme was in parallel with the reduction in the amount of phosphoenzyme formed from Ca(2+) plus ATP. Noteworthy, the mutation nearly eliminated the ability of the enzyme to hydrolyze pNPP which is maximal in the absence of Ca(2+) revealing a major effect of the mutation on the Ca(2+)-independent reactions of the transport cycle. At a pH low enough to protonate the Asp carboxylate the pNPPase activity of Asn879Asp increased, suggesting that the binding of protons to Asn879 is essential for the activities catalyzed by E(2)-like forms of the enzyme.
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Affiliation(s)
- Débora E Rinaldi
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB)-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Ciudad de Buenos Aires, Argentina
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Cura CI, Corradi GR, Rinaldi DE, Adamo HP. High sensibility to reactivation by acidic lipids of the recombinant human plasma membrane Ca2+-ATPase isoform 4xb purified from Saccharomyces cerevisiae. Biochim Biophys Acta 2008; 1778:2757-64. [PMID: 18822268 DOI: 10.1016/j.bbamem.2008.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 11/17/2022]
Abstract
The human plasma membrane Ca2+ pump (isoform 4xb) was expressed in Saccharomyces cerevisiae and purified by calmodulin-affinity chromatography. Under optimal conditions the recombinant enzyme (yPMCA) hydrolyzed ATP in a Ca2+ dependent manner at a rate of 15 micromol/mg/min. The properties of yPMCA were compared to those of the PMCA purified from human red cells (ePMCA). The mobility of yPMCA in SDS-PAGE was the expected for the hPMCA4xb protein but slightly lower than that of ePMCA. Both enzymes achieved maximal activity when supplemented with acidic phospholipids. However, while ePMCA in mixed micelles of phosphatidylcholine-detergent had 30% of its maximal activity, the yPMCA enzyme was nearly inactive. Increasing the phosphatidylcholine content of the micelles did not increase the activity of yPMCA but the activity in the presence of phosphatidylcholine improved by partially removing the detergent. The reactivation of the detergent solubilized yPMCA required specifically acidic lipids and, as judged by the increase in the level of phosphoenzyme, it involved the increase in the amount of active enzyme. These results indicate that the function of yPMCA is highly sensitive to delipidation and the restitution of acidic lipids is needed for a functional enzyme.
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Affiliation(s)
- Carolina I Cura
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB)-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Ciudad de Buenos Aires, Argentina.
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Arienti HM, Guignard SI, Rinaldi DE, Elbarcha OC. [Comparison of 2 serologic methods for the diagnosis of hydatidosis]. Bol Oficina Sanit Panam 1996; 121:221-7. [PMID: 8962664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The sera of 176 patients with epidemiologic antecedents or radiologic and clinical signs of hydatidosis were tested by counter-immunoelectrophoresis (CIE) and enzyme-linked immunoassay (ELISA). A semipurified antigen from cysts of human origin were used for both techniques. The results were compared with those obtained from complementary radiologic studies and were confirmed by examination of excised cysts. Biopsy confirmed the diagnosis of hydatidosis in 65 patients (37%) and revealed the presence of other diseases in the remaining 111 (63%). Of the original 176 patients, 36 (20.4%) were positive by CIE and 62 (35.2%) by ELISA. Both techniques showed an excellent correlation with postsurgical diagnosis; neither produced any false positives, and the ELISA gave false negative results for only three patients (4.6%) with cysts that were infected, infertile, or calcified to some degree. The paper describes standardization of an inexpensive and easy-to-use microELISA.
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Affiliation(s)
- H M Arienti
- Laboratorio de Parasitología, Hospital Rawson, Córdoba, Argentina
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