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Costa A, Resentini F, Buratti S, Bonza MC. Plant Ca 2+-ATPases: From biochemistry to signalling. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119508. [PMID: 37290725 DOI: 10.1016/j.bbamcr.2023.119508] [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: 01/25/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 06/10/2023]
Abstract
Calcium (Ca2+)-ATPases are ATP-dependent enzymes that transport Ca2+ ions against their electrochemical gradient playing the fundamental biological function of keeping the free cytosolic Ca2+ concentration in the submicromolar range to prevent cytotoxic effects. In plants, type IIB autoinhibited Ca2+-ATPases (ACAs) are localised both at the plasma membrane and at the endomembranes including endoplasmic reticulum (ER) and tonoplast and their activity is primarily regulated by Ca2+-dependent mechanisms. Instead, type IIA ER-type Ca2+-ATPases (ECAs) are present mainly at the ER and Golgi Apparatus membranes and are active at resting Ca2+. Whereas research in plants has historically focused on the biochemical characterization of these pumps, more recently the attention has been also addressed on the physiological roles played by the different isoforms. This review aims to highlight the main biochemical properties of both type IIB and type IIA Ca2+ pumps and their involvement in the shaping of cellular Ca2+ dynamics induced by different stimuli.
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Affiliation(s)
- Alex Costa
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy; Institute of Biophysics, National Research Council of Italy (CNR), 20133 Milano, Italy.
| | - Francesca Resentini
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy
| | - Stefano Buratti
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy.
| | - Maria Cristina Bonza
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy.
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2
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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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Astegno A, Bonza MC, Vallone R, La Verde V, D'Onofrio M, Luoni L, Molesini B, Dominici P. Arabidopsis calmodulin-like protein CML36 is a calcium (Ca 2+) sensor that interacts with the plasma membrane Ca 2+-ATPase isoform ACA8 and stimulates its activity. J Biol Chem 2017; 292:15049-15061. [PMID: 28726644 PMCID: PMC5592680 DOI: 10.1074/jbc.m117.787796] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/07/2017] [Indexed: 11/06/2022] Open
Abstract
Calmodulin-like (CML) proteins are major EF-hand-containing, calcium (Ca2+)-binding proteins with crucial roles in plant development and in coordinating plant stress tolerance. Given their abundance in plants, the properties of Ca2+ sensors and identification of novel target proteins of CMLs deserve special attention. To this end, we recombinantly produced and biochemically characterized CML36 from Arabidopsis thaliana We analyzed Ca2+ and Mg2+ binding to the individual EF-hands, observed metal-induced conformational changes, and identified a physiologically relevant target. CML36 possesses two high-affinity Ca2+/Mg2+ mixed binding sites and two low-affinity Ca2+-specific sites. Binding of Ca2+ induced an increase in the α-helical content and a conformational change that lead to the exposure of hydrophobic regions responsible for target protein recognition. Cation binding, either Ca2+ or Mg2+, stabilized the secondary and tertiary structures of CML36, guiding a large structural transition from a molten globule apo-state to a compact holoconformation. Importantly, through in vitro binding and activity assays, we showed that CML36 interacts directly with the regulative N terminus of the Arabidopsis plasma membrane Ca2+-ATPase isoform 8 (ACA8) and that this interaction stimulates ACA8 activity. Gene expression analysis revealed that CML36 and ACA8 are co-expressed mainly in inflorescences. Collectively, our results support a role for CML36 as a Ca2+ sensor that binds to and modulates ACA8, uncovering a possible involvement of the CML protein family in the modulation of plant-autoinhibited Ca2+ pumps.
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Affiliation(s)
- Alessandra Astegno
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Maria Cristina Bonza
- the Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milano, Italy
| | - Rosario Vallone
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Valentina La Verde
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Mariapina D'Onofrio
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Laura Luoni
- the Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milano, Italy
| | - Barbara Molesini
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Paola Dominici
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
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Calì T, Frizzarin M, Luoni L, Zonta F, Pantano S, Cruz C, Bonza MC, Bertipaglia I, Ruzzene M, De Michelis MI, Damiano N, Marin O, Zanni G, Zanotti G, Brini M, Lopreiato R, Carafoli E. The ataxia related G1107D mutation of the plasma membrane Ca 2+ ATPase isoform 3 affects its interplay with calmodulin and the autoinhibition process. Biochim Biophys Acta Mol Basis Dis 2016; 1863:165-173. [PMID: 27632770 DOI: 10.1016/j.bbadis.2016.09.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/05/2016] [Accepted: 09/09/2016] [Indexed: 11/20/2022]
Abstract
The plasma membrane Ca2+ ATPases (PMCA pumps) have a long, cytosolic C-terminal regulatory region where a calmodulin-binding domain (CaM-BD) is located. Under basal conditions (low Ca2+), the C-terminal tail of the pump interacts with autoinhibitory sites proximal to the active center of the enzyme. In activating conditions (i.e., high Ca2+), Ca2+-bound CaM displaces the C-terminal tail from the autoinhibitory sites, restoring activity. We have recently identified a G1107D replacement within the CaM-BD of isoform 3 of the PMCA pump in a family affected by X-linked congenital cerebellar ataxia. Here, we investigate the effects of the G1107D replacement on the interplay of the mutated CaM-BD with both CaM and the pump core, by combining computational, biochemical and functional approaches. We provide evidence that the affinity of the isolated mutated CaM-BD for CaM is significantly reduced with respect to the wild type (wt) counterpart, and that the ability of CaM to activate the pump in vitro is thus decreased. Multiscale simulations support the conclusions on the detrimental effect of the mutation, indicating reduced stability of the CaM binding. We further show that the G1107D replacement impairs the autoinhibition mechanism of the PMCA3 pump as well, as the introduction of a negative charge perturbs the contacts between the CaM-BD and the pump core. Thus, the mutation affects both the ability of the pump to optimally transport Ca2+ in the activated state, and the autoinhibition mechanism in its resting state.
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Affiliation(s)
- Tito Calì
- Department of Biomedical Sciences, University of Padova, Italy
| | | | - Laura Luoni
- Department of Biosciences, University of Milano, Italy
| | - Francesco Zonta
- Shanghai Institute of Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | | | - Carlos Cruz
- Aggeu Magalhães Research Center - CpqAM, Oswaldo Cruz Foundation - FioCruz, Rio de Janeiro, Brazil; Institut Pasteur de Montevideo, Uruguay
| | | | | | - Maria Ruzzene
- Department of Biomedical Sciences, University of Padova, Italy
| | | | - Nunzio Damiano
- Department of Biomedical Sciences, University of Padova, Italy
| | - Oriano Marin
- Department of Biomedical Sciences, University of Padova, Italy
| | - Ginevra Zanni
- Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Marisa Brini
- Department of Biology, University of Padova, Italy
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Aseervatham J, Tran L, Machaca K, Boudker O. The Role of Flexible Loops in Folding, Trafficking and Activity of Equilibrative Nucleoside Transporters. PLoS One 2015; 10:e0136779. [PMID: 26406980 PMCID: PMC4583308 DOI: 10.1371/journal.pone.0136779] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/07/2015] [Indexed: 11/25/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs) are integral membrane proteins, which reside in plasma membranes of all eukaryotic cells and mediate thermodynamically downhill transport of nucleosides. This process is essential for nucleoside recycling, and also plays a key role in terminating adenosine-mediated cellular signaling. Furthermore, ENTs mediate the uptake of many drugs, including anticancer and antiviral nucleoside analogues. The structure and mechanism, by which ENTs catalyze trans-membrane transport of their substrates, remain unknown. To identify the core of the transporter needed for stability, activity, and for its correct trafficking to the plasma membrane, we have expressed human ENT deletion mutants in Xenopus laevis oocytes and determined their localization, transport properties and susceptibility to inhibition. We found that the carboxyl terminal trans-membrane segments are essential for correct protein folding and trafficking. In contrast, the soluble extracellular and intracellular loops appear to be dispensable, and must be involved in the fine-tuning of transport regulation.
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Affiliation(s)
- Jaya Aseervatham
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Qatar foundation, Education City, Doha, Qatar
| | - Lucky Tran
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, United States of America
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Qatar foundation, Education City, Doha, Qatar
| | - Olga Boudker
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, United States of America
- * E-mail:
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6
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Limonta M, Romanowsky S, Olivari C, Bonza MC, Luoni L, Rosenberg A, Harper JF, De Michelis MI. ACA12 is a deregulated isoform of plasma membrane Ca²⁺-ATPase of Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 2014; 84:387-97. [PMID: 24101142 PMCID: PMC4104672 DOI: 10.1007/s11103-013-0138-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 09/29/2013] [Indexed: 05/08/2023]
Abstract
Plant auto-inhibited Ca²⁺-ATPases (ACA) are crucial in defining the shape of calcium transients and therefore in eliciting plant responses to various stimuli. Arabidopsis thaliana genome encodes ten ACA isoforms that can be divided into four clusters based on gene structure and sequence homology. While isoforms from clusters 1, 2 and 4 have been characterized, virtually nothing is known about members of cluster 3 (ACA12 and ACA13). Here we show that a GFP-tagged ACA12 localizes at the plasma membrane and that expression of ACA12 rescues the phenotype of partial male sterility of a null mutant of the plasma membrane isoform ACA9, thus providing genetic evidence that ACA12 is a functional plasma membrane-resident Ca²⁺-ATPase. By ACA12 expression in yeast and purification by CaM-affinity chromatography, we show that, unlike other ACAs, the activity of ACA12 is not stimulated by CaM. Moreover, full length ACA12 is able to rescue a yeast mutant deficient in calcium pumps. Analysis of single point ACA12 mutants suggests that ACA12 loss of auto-inhibition can be ascribed to the lack of two acidic residues--highly conserved in other ACA isoforms--localized at the cytoplasmic edge of the second and third transmembrane segments. Together, these results support a model in which the calcium pump activity of ACA12 is primarily regulated by increasing or decreasing mRNA expression and/or protein translation and degradation.
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Affiliation(s)
- Margherita Limonta
- Dipartimento di Bioscienze, Università degli Studi di Milano, Istituto di Biofisica del CNR, Sezione di Milano, via G. Celoria 26, 20133 Milano, Italy
| | - Shawn Romanowsky
- Biochemistry Department, University of Nevada, Reno, Nevada 89557
| | - Claudio Olivari
- Dipartimento di Bioscienze, Università degli Studi di Milano, Istituto di Biofisica del CNR, Sezione di Milano, via G. Celoria 26, 20133 Milano, Italy
| | - Maria Cristina Bonza
- Dipartimento di Bioscienze, Università degli Studi di Milano, Istituto di Biofisica del CNR, Sezione di Milano, via G. Celoria 26, 20133 Milano, Italy
| | - Laura Luoni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Istituto di Biofisica del CNR, Sezione di Milano, via G. Celoria 26, 20133 Milano, Italy
| | - Alexa Rosenberg
- Biochemistry Department, University of Nevada, Reno, Nevada 89557
| | | | - Maria Ida De Michelis
- Dipartimento di Bioscienze, Università degli Studi di Milano, Istituto di Biofisica del CNR, Sezione di Milano, via G. Celoria 26, 20133 Milano, Italy
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Huda KMK, Banu MSA, Tuteja R, Tuteja N. Global calcium transducer P-type Ca²⁺-ATPases open new avenues for agriculture by regulating stress signalling. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3099-109. [PMID: 23918957 DOI: 10.1093/jxb/ert182] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Food security is in danger under the continuous growing threat of various stresses including climate change and global warming, which ultimately leads to a reduction in crop yields. Calcium plays a very important role in many signal transduction pathways including stress signalling. Different extracellular stimuli trigger increases in cytosolic calcium, which is detrimental to plants. To cope with such stresses, plants need to develop efficient efflux mechanisms to maintain ionic homeostasis. The Ca(2+)-ATPases are members of the P-type ATPase superfamily, which perform many fundamental processes in organisms by actively transporting ions across cellular membranes. In recent years, many studies have revealed that, as well as efflux mechanisms, Ca(2+)-ATPases also play critical roles in sensing calcium fluctuations and relaying downstream signals by activating definitive targets, thus modulating corresponding metabolic pathways. As calcium-activated calmodulin (CaM) is reported to play vital roles in stress tolerance, the presence of a unique CaM-binding site in type IIB Ca(2+)-ATPases indicates their potential role in biotic as well as abiotic stress tolerance. The key roles of Ca(2+)-ATPases in transport systems and stress signalling in cellular homeostasis are addressed in this review. A complete understanding of plant defence mechanisms under stress will allow bioengineering of improved crop plants, which will be crucial for food security currently observed worldwide in the context of global climate changes. Overall, this article covers classification, evolution, structural aspects of Ca(2+)-ATPases, and their emerging roles in plant stress signalling.
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Affiliation(s)
- Kazi Md Kamrul Huda
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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8
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Kamrul Huda KM, Yadav S, Akhter Banu MS, Trivedi DK, Tuteja N. Genome-wide analysis of plant-type II Ca(2+)ATPases gene family from rice and Arabidopsis: potential role in abiotic stresses. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 65:32-47. [PMID: 23416494 DOI: 10.1016/j.plaphy.2013.01.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 01/18/2013] [Indexed: 05/05/2023]
Abstract
The Plant Ca(2+)ATPases are members of the P-type ATPase superfamily and play essential roles in pollen tube growth, vegetative development, inflorescence architecture, stomatal opening or closing as well as transport of Ca(2+), Mn(2+) and Zn(2+). Their role in abiotic stress adaptation by activation of different signaling pathways is emerging. In Arabidopsis, the P-type Ca(2+)ATPases can be classified in two distinct groups: type IIA (ECA) and type IIB (ACA). The availability of rice genome sequence allowed performing a genome-wide search for P-type Ca(2+)ATPases proteins, and the comparison of the identified proteins with their homologs in Arabidopsis model plant. In the present study, we identified the P-type II Ca(2+)ATPases from rice by analyzing their phylogenetic relationship, multiple alignment, cis-regulatory elements, protein domains, motifs and homology percentage. The phylogenetic analysis revealed that rice type IIA Ca(2+)ATPases clustered with Arabidopsis type IIA Ca(2+)ATPases and showed high sequence similarity within the group, whereas rice type IIB Ca(2+)ATPases presented variable sequence similarities with Arabidopsis type IIB members. The protein homology modeling, identification of putative transmembrane domains and conserved motifs of rice P-type II Ca(2+)ATPases provided information on their functions and structural architecture. The analysis of P-type II Ca(2+)ATPases promoter regions in rice showed multiple stress-induced cis-acting elements. The expression profile analysis indicated vital roles of P-type II Ca(2+)ATPases in stress signaling, plant development and abiotic stress responses. The comprehensive analysis and expression profiling provided a critical platform for functional characterization of P-type II Ca(2+)ATPase genes that could be applied in engineering crop plants with modified calcium signaling and homeostatic pathways.
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Affiliation(s)
- Kazi Md Kamrul Huda
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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A bimodular mechanism of calcium control in eukaryotes. Nature 2012; 491:468-72. [PMID: 23086147 DOI: 10.1038/nature11539] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 08/23/2012] [Indexed: 11/08/2022]
Abstract
Calcium ions (Ca(2+)) have an important role as secondary messengers in numerous signal transduction processes, and cells invest much energy in controlling and maintaining a steep gradient between intracellular (∼0.1-micromolar) and extracellular (∼2-millimolar) Ca(2+) concentrations. Calmodulin-stimulated calcium pumps, which include the plasma-membrane Ca(2+)-ATPases (PMCAs), are key regulators of intracellular Ca(2+) in eukaryotes. They contain a unique amino- or carboxy-terminal regulatory domain responsible for autoinhibition, and binding of calcium-loaded calmodulin to this domain releases autoinhibition and activates the pump. However, the structural basis for the activation mechanism is unknown and a key remaining question is how calmodulin-mediated PMCA regulation can cover both basal Ca(2+) levels in the nanomolar range as well as micromolar-range Ca(2+) transients generated by cell stimulation. Here we present an integrated study combining the determination of the high-resolution crystal structure of a PMCA regulatory-domain/calmodulin complex with in vivo characterization and biochemical, biophysical and bioinformatics data that provide mechanistic insights into a two-step PMCA activation mechanism mediated by calcium-loaded calmodulin. The structure shows the entire PMCA regulatory domain and reveals an unexpected 2:1 stoichiometry with two calcium-loaded calmodulin molecules binding to different sites on a long helix. A multifaceted characterization of the role of both sites leads to a general structural model for calmodulin-mediated regulation of PMCAs that allows stringent, highly responsive control of intracellular calcium in eukaryotes, making it possible to maintain a stable, basal level at a threshold Ca(2+) concentration, where steep activation occurs.
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Giacometti S, Marrano CA, Bonza MC, Luoni L, Limonta M, De Michelis MI. Phosphorylation of serine residues in the N-terminus modulates the activity of ACA8, a plasma membrane Ca2+-ATPase of Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1215-24. [PMID: 22090438 PMCID: PMC3276087 DOI: 10.1093/jxb/err346] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 09/20/2011] [Accepted: 10/04/2011] [Indexed: 05/23/2023]
Abstract
ACA8 is a plasma membrane-localized isoform of calmodulin (CaM)-regulated Ca(2+)-ATPase of Arabidopsis thaliana. Several phosphopeptides corresponding to portions of the regulatory N-terminus of ACA8 have been identified in phospho-proteomic studies. To mimic phosphorylation of the ACA8 N-terminus, each of the serines found to be phosphorylated in those studies (Ser19, Ser22, Ser27, Ser29, Ser57, and Ser99) has been mutated to aspartate. Mutants have been expressed in Saccharomyces cerevisiae and characterized: mutants S19D and S57D--and to a lesser extent also mutants S22D and S27D--are deregulated, as shown by their low activation by CaM and by tryptic cleavage of the N-terminus. The His-tagged N-termini of wild-type and mutant ACA8 (6His-(1)M-I(116)) were expressed in Escherichia coli, affinity-purified, and used to analyse the kinetics of CaM binding by surface plasmon resonance. All the analysed mutations affect the kinetics of interaction with CaM to some extent: in most cases, the altered kinetics result in marginal changes in affinity, with the exception of mutants S57D (K(D) ≈ 10-fold higher than wild-type ACA8) and S99D (K(D) about half that of wild-type ACA8). The ACA8 N-terminus is phosphorylated in vitro by two isoforms of A. thaliana calcium-dependent protein kinase (CPK1 and CPK16); phosphorylation of mutant 6His-(1)M-I(116) peptides shows that CPK16 is able to phosphorylate the ACA8 N-terminus at Ser19 and at Ser22. The possible physiological implications of the subtle modulation of ACA8 activity by phosphorylation of its N-terminus are discussed.
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11
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Heintz D, Gallien S, Compagnon V, Berna A, Suzuki M, Yoshida S, Muranaka T, Van Dorsselaer A, Schaeffer C, Bach TJ, Schaller H. Phosphoproteome exploration reveals a reformatting of cellular processes in response to low sterol biosynthetic capacity in Arabidopsis. J Proteome Res 2012; 11:1228-39. [PMID: 22182420 DOI: 10.1021/pr201127u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Sterols are membrane-bound isoprenoid lipids that are required for cell viability and growth. In plants, it is generally assumed that 3-hydroxy-3-methylglutaryl-CoA-reductase (HMGR) is a key element of their biosynthesis, but the molecular regulation of that pathway is largely unknown. In an attempt to identify regulators of the biosynthetic flux from acyl-CoA toward phytosterols, we compared the membrane phosphoproteome of wild-type Arabidopsis thaliana and of a mutant being deficient in HMGR1. We performed a N-terminal labeling of microsomal peptides with a trimethoxyphenyl phosphonium (TMPP) derivative, followed by a quantitative assessment of phosphopeptides with a spectral counting method. TMPP derivatization of peptides resulted in an improved LC-MS/MS detection due to increased hydrophobicity in chromatography and ionization efficiency in electrospray. The phosphoproteome coverage was 40% higher with this methodology. We further found that 31 proteins were in a different phosphorylation state in the hmgr1-1 mutant as compared with the wild-type. One-third of these proteins were identified based on novel phosphopeptides. This approach revealed that phosphorylation changes in the Arabidopsis membrane proteome targets major cellular processes such as transports, calcium homeostasis, photomorphogenesis, and carbohydrate synthesis. A reformatting of these processes appears to be a response of a genetically reduced sterol biosynthesis.
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Affiliation(s)
- Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-Unité Propre de Recherche 2357, Université de Strasbourg , 28 rue Goethe, 67083 Strasbourg, France
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12
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Reyes G, Nivillac NMI, Chalsev M, Coe IR. Analysis of recombinant tagged equilibrative nucleoside transporter 1 (ENT1) expressed in E. coli. Biochem Cell Biol 2011; 89:246-55. [PMID: 21455275 DOI: 10.1139/o10-155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nucleoside transporters (NTs) are integral membrane proteins necessary for the cellular entry of nucleoside analog drugs used in chemotherapeutic treatment of conditions such as cancer and viral or parasitic infections. NTs are also the targets of certain drugs used in the treatment of various cardiovascular conditions. Because of the importance of NTs in drug uptake, determination of the three-dimensional structure of these proteins, particularly hENT1, has the potential to improve these treatments through structure-based design of more specifically targeted and transported drugs. In this paper, we use NMR spectroscopy to investigate the structure of the large intracellular loop between transmembrane domains 6 and 7 and we also describe a method for the successful overexpression of full-length hENT1 in a bacterial system. Recombinant tandem histidine-affinity (HAT) and 3×FLAG tagged hENT1 was overexpressed in E. coli, affinity purified, and functionally characterized by nitrobenzylthioinosine (NBTI) binding. Anti-3×FLAG immunodetection confirmed the expression of N-HAT-3×FLAG-hENT1, while increased NBTI binding (3.2-fold compared with controls) confirmed the conformational integrity of the recombinant hENT1 within the bacterial inner membrane. Yields of recombinant hENT1 using this approach were ~15 µg/L of bacterial culture and this approach provides a basis for large-scale production of protein for a variety of purposes.
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Affiliation(s)
- German Reyes
- Department of Biology, York University, Toronto, ON, Canada
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Bonza MC, De Michelis MI. The plant Ca2+ -ATPase repertoire: biochemical features and physiological functions. PLANT BIOLOGY (STUTTGART, GERMANY) 2011; 13:421-30. [PMID: 21489092 DOI: 10.1111/j.1438-8677.2010.00405.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ca(2+)-ATPases are P-type ATPases that use the energy of ATP hydrolysis to pump Ca(2+) from the cytoplasm into intracellular compartments or into the apoplast. Plant cells possess two types of Ca(2+) -pumping ATPase, named ECAs (for ER-type Ca(2+)-ATPase) and ACAs (for auto-inhibited Ca(2+)-ATPase). Each type comprises different isoforms, localised on different membranes. Here, we summarise available knowledge of the biochemical characteristics and the physiological role of plant Ca(2+)-ATPases, greatly improved after gene identification, which allows both biochemical analysis of single isoforms through heterologous expression in yeast and expression profiling and phenotypic analysis of single isoform knock-out mutants.
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Affiliation(s)
- M C Bonza
- Dipartimento di Biologia L. Gorini, Università degli Studi di Milano, Istituto di Biofisica del CNR, Sezione di Milano, Milano, Italy
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14
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Ca2+ Pumps and Ca2+ Antiporters in Plant Development. SIGNALING AND COMMUNICATION IN PLANTS 2011. [DOI: 10.1007/978-3-642-14369-4_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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Bonza MC, Luoni L. Plant and animal type 2B Ca2+-ATPases: evidence for a common auto-inhibitory mechanism. FEBS Lett 2010; 584:4783-8. [PMID: 21073872 DOI: 10.1016/j.febslet.2010.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
Abstract
Plant auto-inhibited Ca(2+)-ATPase 8 (ACA8) and animal plasma membrane Ca(2+)-ATPase 4b (PMCA4b) are representatives of plant and animal 2B P-type ATPases with a regulatory auto-inhibitory domain localized at the N- and C-terminus, respectively. To check whether the regulatory domain works independently of its terminal localization and if auto-inhibitory domains of different organisms are interchangeable, a mutant in which the N-terminus of ACA8 is repositioned at the C-terminus and chimeras in which PMCA4b C-terminus is fused to the N- or C-terminus of ACA8 were analysed in the yeast mutant K616 devoid of endogenous Ca(2+)-ATPases. Results show that the regulatory function of the terminal domain is independent from its position in ACA8 and that the regulatory domain belonging to PMCA4b is able to at least partially auto-inhibit ACA8.
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Bonza MC, Martin H, Kang M, Lewis G, Greiner T, Giacometti S, Van Etten JL, De Michelis MI, Thiel G, Moroni A. A functional calcium-transporting ATPase encoded by chlorella viruses. J Gen Virol 2010; 91:2620-9. [PMID: 20573858 PMCID: PMC3052600 DOI: 10.1099/vir.0.021873-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Calcium-transporting ATPases (Ca2+ pumps) are major players in maintaining calcium homeostasis in the cell and have been detected in all cellular organisms. Here, we report the identification of two putative Ca2+ pumps, M535L and C785L, encoded by chlorella viruses MT325 and AR158, respectively, and the functional characterization of M535L. Phylogenetic and sequence analyses place the viral proteins in group IIB of P-type ATPases even though they lack a typical feature of this class, a calmodulin-binding domain. A Ca2+ pump gene is present in 45 of 47 viruses tested and is transcribed during virus infection. Complementation analysis of the triple yeast mutant K616 confirmed that M535L transports calcium ions and, unusually for group IIB pumps, also manganese ions. In vitro assays show basal ATPase activity. This activity is inhibited by vanadate, but, unlike that of other Ca2+ pumps, is not significantly stimulated by either calcium or manganese. The enzyme forms a 32P-phosphorylated intermediate, which is inhibited by vanadate and not stimulated by the transported substrate Ca2+, thus confirming the peculiar properties of this viral pump. To our knowledge this is the first report of a functional P-type Ca2+-transporting ATPase encoded by a virus.
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Affiliation(s)
- Maria Cristina Bonza
- Dipartimento di Biologia e Istituto di Biofisica del CNR, Università degli Studi di Milano, Milano, Italy
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