Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca2+-ATPase

Tadini‐Buoninsegni, Francesco; Moncelli, Maria Rosa; Peruzzi, Niccolò; Ninham, Barry W.; Dei, Luigi; Nostro, Pierandrea Lo

doi:10.1038/srep14282

Cited by 16 publications

(15 citation statements)

References 55 publications

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“…To investigate the interaction of these polyphenolic compounds with SR Ca 2+ -ATPase and its possible inhibition, we performed current measurements on SR vesicles adsorbed on a SSM. The SSM technique allows direct measurements of charge displacements within the transport protein yielding valuable information about the ion transport mechanism [ 32 , 56 , 57 ]. The technique is also well suited for the analysis of inhibitor interactions with membrane transporters [ 33 , 58 ].…”

Section: Resultsmentioning

confidence: 99%

Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues

et al. 2016

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Protection of plants against bacterial diseases still mainly relies on the use of chemical pesticides, which in Europe correspond essentially to copper-based compounds. However, recently plant diseases control is oriented towards a rational use of molecules and extracts, generally with natural origin, with lower intrinsic toxicity and a reduced negative environmental impact. In this work, polyphenolic extracts from vegetable no food/feed residues of typical Mediterranean crops, as Olea europaea, Cynara scolymus, and Vitis vinifera were obtained and their inhibitory activity on the Type Three Secretion System (TTSS) and the Quorum Sensing (QS) of the Gram-negative phytopathogenic bacterium Pseudomonas savastanoi pv. nerii strain Psn23 was assessed. Extract from green tea (Camellia sinensis) was used as a positive control. Collectively, the data obtained through gfp-promoter fusion system and real-time PCR show that all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability. Extracts from green tea and grape seeds were shown to be the most active. Such activity was confirmed in planta by a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco. By using a newly developed Congo red assay and an ELISA test, we demonstrated that the TTSS-targeted activity of these polyphenolic extracts also affects the TTSS pilus assembly. In consideration of the potential application of polyphenolic extracts in plant protection, the absence of any toxicity of these polyphenolic compounds was also assessed. A widely and evolutionary conserved molecular target such as Ca2+-ATPase, essential for the survival of any living organism, was used for the toxicity assessment.

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Section: Resultsmentioning

confidence: 99%

Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues

et al. 2016

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“…Additional data consistent with the involvement of anions in the function of the Na + /K + -ATPase comes from extensive studies characterizing a Hofmeister effect whereby chaotropic ions stabilize the E1P state (25,37) and slow the E1P-E2P interconversion rate (38). While previous studies have ascribed the Hofmeister effect in the Na + /K + -ATPase and the sarcoplasmic reticulum Ca 2+ -ATPase to modified electrostatic interactions at the membrane/enzyme/cytoplasm interface (38)(39)(40), the existence of an anion binding site near this interface is not inconsistent with these data. Future simulation work will help to test this hypothesis by predicting binding affinities for different anionic chemical species.…”

Section: Molecular Mechanism Of Selectivity In Namentioning

confidence: 90%

Molecular simulations and free-energy calculations suggest conformation-dependent anion binding to a cytoplasmic site as a mechanism for Na+/K+-ATPase ion selectivity

Razavi

Delemotte

Berlin

et al. 2017

Journal of Biological Chemistry

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Na+ /K + -ATPase transports Na + and K + ions across the cell membrane via an ion-binding site becoming alternatively accessible to the intra-and extracellular milieu by conformational transitions that confer marked changes in ion-binding stoichiometry and selectivity. To probe the mechanism of these changes, we used molecular simulation and free energy perturbation approaches to identify probable protonation states of Na + and K + coordinating residues in E1P and E2P conformations of Na + /K + -ATPase. Analysis of these simulations revealed a molecular mechanism responsible for the change in protonation state: the conformation-dependent binding of an anion (a chloride ion in our simulations) to a previously unrecognized cytoplasmic site in the loop between transmembrane helices 8 and 9, which influences the electrostatic potential of the crucial Na + -coordinating residue D926. This mechanistic model is consistent with experimental observations and provides a molecular-level picture of how E1P to E2P enzyme conformational transitions are coupled to changes in ion binding stoichiometry and selectivity. Na + /K + -ATPase is a membrane protein that actively transports sodium ions out of the cell while importing potassium ions, both against their electrochemical gradients, thus providing potential energy necessary for many essential cellular functions (1-3). Malfunction of Na + /K + -ATPase has been linked to numerous diseases including impaired memory and learning, familial hemiplegic migraine 2, rapid-onset dystonia Parkinsonism, and heart failure (4-6), thus, Na + /K + -ATPase is an important target for treatment of brain and heart conditions (7,8).By harnessing chemical energy stored in ATP, the Na + /K + -ATPase cycles between two major conformational states during active ion pumping: one state with high affinity for sodium ions (E1), and a second with high affinity for potassium ion (E2).While the complete mechanism of function of the Na Na+ /K + -ATPase and ion selectivity 2 more complicated, involving several conformational transitions described more fully in the Post-Albers scheme (9-11), here we focus on the sodium-bond E1P and potassium-bound E2P states (i.e. phosphorylated E1 and E2), for which crystal structures are available (12)(13)(14)(15)(16)(17). One of the central features of ion transport by the Na + /K + -ATPase is a change in ion selectivity between E1 and E2 conformations (3). The origin of this selectivity change has been a focus of Na + /K + -ATPase research since its discovery by Jens Christian Skou in 1957 (1). Extensive mutational studies have identified key residues involved in ion binding, which include five acidic residues: Asp804, Asp808, and Asp926, Glu327 and Glu779 (13) whose orientation, distance, and ion coordination have been proposed to be involved in determining selectivity (3). The first crystal structure of the Na + /K + -ATPase, solved for the potassium-bound E2P state in 2007 (15) and later followed by several higher resolution structures (14,16,17), revealed a ...

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“…attributable to the translocation of calcium into the proteoliposomes during the first SERCA transport cycle (27,34,35). To confirm that the measured current is due to SERCA, we performed an ATP jump in the presence of thapsigargin (40), which caused nearly complete suppression of the current transient (not shown).…”

Section: Substrate Dependence Of Serca-phospholamban Interactionsmentioning

confidence: 99%

“…The proteoliposomes were adsorbed to the SSM and activated by a calcium and/or ATP concentration jump. Following SERCA activation, an electrical current was detected related to the displacement of calcium ions within the protein during the first catalytic cycle (27,34,35). These results from pre-steady-state charge translocation during the first SERCA turnover were compared with steady-state measurements of ATPase activity during continuous turnover (32,33).…”

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confidence: 99%

Conformational memory in the association of the transmembrane protein phospholamban with the sarcoplasmic reticulum calcium pump SERCA

Smeazzetto

Armanious

Moncelli

et al. 2017

Journal of Biological Chemistry

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The sarcoplasmic reticulum Ca-ATPase SERCA promotes muscle relaxation by pumping calcium ions from the cytoplasm into the sarcoplasmic reticulum. SERCA activity is regulated by a variety of small transmembrane peptides, most notably by phospholamban in cardiac muscle and sarcolipin in skeletal muscle. However, how phospholamban and sarcolipin regulate SERCA is not fully understood. In the present study, we evaluated the effects of phospholamban and sarcolipin on calcium translocation and ATP hydrolysis by SERCA under conditions that mimic environments in sarcoplasmic reticulum membranes. For pre-steady-state current measurements, proteoliposomes containing SERCA and phospholamban or sarcolipin were adsorbed to a solid-supported membrane and activated by substrate concentration jumps. We observed that phospholamban altered ATP-dependent calcium translocation by SERCA within the first transport cycle, whereas sarcolipin did not. Using pre-steady-state charge (calcium) translocation and steady-state ATPase activity under substrate conditions (various calcium and/or ATP concentrations) promoting particular conformational states of SERCA, we found that the effect of phospholamban on SERCA depends on substrate preincubation conditions. Our results also indicated that phospholamban can establish an inhibitory interaction with multiple SERCA conformational states with distinct effects on SERCA's kinetic properties. Moreover, we noted multiple modes of interaction between SERCA and phospholamban and observed that once a particular mode of association is engaged it persists throughout the SERCA transport cycle and multiple turnover events. These observations are consistent with conformational memory in the interaction between SERCA and phospholamban, thus providing insights into the physiological role of phospholamban and its regulatory effect on SERCA transport activity.

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Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca2+-ATPase

Cited by 16 publications

References 55 publications

Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues

Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues

Molecular simulations and free-energy calculations suggest conformation-dependent anion binding to a cytoplasmic site as a mechanism for Na+/K+-ATPase ion selectivity

Conformational memory in the association of the transmembrane protein phospholamban with the sarcoplasmic reticulum calcium pump SERCA

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