Functional identification of electrogenic Na<sup>+</sup>‐translocating ATPase in the plasma membrane of the halotolerant microalga <i>Dunaliella maritima</i>

Попова, Л. Г.; Shumkova, G. A.; Andreev, I. M.; Balnokin, Yu. V.

doi:10.1016/j.febslet.2005.07.087

Cited by 26 publications

(20 citation statements)

References 17 publications

(20 reference statements)

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“…Biochemical evidence has pointed to the presence an electrogenic, vanadate-sensitive, ouabain-resistant Na + -ATPase in the plasma membrane of marine chlorophytes (Popova et al, 1999, 2005; Gimmler, 2000) and chlorophyte expressed sequence tags with similarity to Na + /K + -ATPase have been identified (Barrero-Gil et al, 2005). Both chlorophytes analyzed in this work contain sequences with strong similarity to an animal Na + /K + -ATPase (Figure 8).…”

Section: Resultsmentioning

confidence: 99%

Evolution of Plant P-Type ATPases

Pedersen¹,

Axelsen²,

Harper³

et al. 2012

Front. Plant Sci.

124

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Five organisms having completely sequenced genomes and belonging to all major branches of green plants (Viridiplantae) were analyzed with respect to their content of P-type ATPases encoding genes. These were the chlorophytes Ostreococcus tauri and Chlamydomonas reinhardtii, and the streptophytes Physcomitrella patens (a non-vascular moss), Selaginella moellendorffii (a primitive vascular plant), and Arabidopsis thaliana (a model flowering plant). Each organism contained sequences for all five subfamilies of P-type ATPases. Whereas Na+ and H+ pumps seem to mutually exclude each other in flowering plants and animals, they co-exist in chlorophytes, which show representatives for two kinds of Na+ pumps (P2C and P2D ATPases) as well as a primitive H+-ATPase. Both Na+ and H+ pumps also co-exist in the moss P. patens, which has a P2D Na+-ATPase. In contrast to the primitive H+-ATPases in chlorophytes and P. patens, the H+-ATPases from vascular plants all have a large C-terminal regulatory domain as well as a conserved Arg in transmembrane segment 5 that is predicted to function as part of a backflow protection mechanism. Together these features are predicted to enable H+ pumps in vascular plants to create large electrochemical gradients that can be modulated in response to diverse physiological cues. The complete inventory of P-type ATPases in the major branches of Viridiplantae is an important starting point for elucidating the evolution in plants of these important pumps.

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Section: Resultsmentioning

confidence: 99%

Evolution of Plant P-Type ATPases

Pedersen¹,

Axelsen²,

Harper³

et al. 2012

Front. Plant Sci.

124

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“…The ionic compo sition of the cytoplasm is restored owing to operation of the Na + transporting ATPase. This specialized mechanism located in the plasma membrane of D. maritima is responsible for Na + extrusion from the cells to the external medium [22]. The results of this work provide evidence that PSII of the halotolerant alga D. maritima is sensitive to hyperosmotic salt shock, similarly to PSII of glyco phytic plants [2].…”

Section: Discussionmentioning

confidence: 90%

Responses of photosynthetic apparatus of the halotolerant microalga Dunalliella maritima to hyperosmotic salt shock

Захожий

Matalin

Попова

et al. 2011

Russ J Plant Physiol

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Chlorophyll fluorescence induction curves were used as a means to assess the functional condition of the photosynthetic apparatus in cells of the halotolerant green microalga Dunaliella maritima (Massjuk) (division Chlorophyta) exposed to hyperosmotic salt shock of various intensities. The shock was caused by the transfer of algal cells grown in the medium with 0.5 M NaCl to the media with elevated NaCl concentra tions (1.0, 1.5, and 2.0 M). Parameters of chlorophyll fluorescence (F 0 , F m , F 0 ', ) were measured by means of a specialized pulse amplitude modulation fluorometer PAM 2100. In addition, the rate of photo synthetic oxygen evolution as well as the intracellular Na + and glycerol content (the main osmolyte in this microalga) were determined. The hyperosmotic salt shock was found to elevate the intracellular Na + content and reduce the functional activity of PSII in D. maritima. The suppression of PSII activity was evident from the decrease in the maximal quantum yield of photochemical energy conversion in PSII, the decreased rate of linear electron transport, the increased reduction of the primary acceptor Q A , and the suppression of pho tosynthetic O 2 evolution. The functional activity of PSII recovered gradually along with restoration of osmotic and ionic balance in algal cells. It is proposed that PSI ensures energy supply during cell responses of D. maritima to hyperosmotic salt shock.

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“…H + efflux does not occur directly via Na + -stimulated ATPase but is driven by the membrane potential generated during Na + -stimulated ATPase operation. The operation of Na + -stimulated ATPase as a Na + uniporter has been previously reported in the halotolerant microalga Dunaliella maritima [28] while Na + -translocating ATPase in the marine microalga Tetraselmis viridis operates as a Na + /H + exchanger [30]. …”

Section: Discussionmentioning

confidence: 99%

“…[28] with slight modification. The reaction mixture (1 ml) contained 0.4 M sucrose, 20 mM Hepes-Tris buffer pH 7.6, 1 mM MgSO 4 , 3 μM oxonol VI and proteoliposomes (25 μg protein).…”

Section: Methodsmentioning

confidence: 99%

“…The membrane vesicles could take up Na + when supplied with ATP. In the halotolerant microalga Dunaliella maritima , it was found that Na + uptake across the plasma membrane by Na + -ATPase is electrogenic [28] and the mechanism of Na + transport by Na + -ATPase is suggested to operate as an Na + uniporter which carries only Na + ions for transport across the plasma membrane while the transport of H + , a counterion, is driven by an electrical membrane potential generated by Na + -ATPase [29]. On the contrary, the mechanism of Na + transport across the plasma membrane of the marine microalga Tetraselmis viridis by Na + -ATPase is suggested to operate as an Na + /H + exchanger which catalyzes an exchange of Na + for H + [30].…”

Section: Introductionmentioning

confidence: 99%

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Na+-stimulated ATPase of alkaliphilic halotolerant cyanobacterium Aphanothece halophytica translocates Na+ into proteoliposomes via Na+ uniport mechanism

Soontharapirakkul

Incharoensakdi

2010

BMC Biochemistry

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BackgroundWhen cells are exposed to high salinity conditions, they develop a mechanism to extrude excess Na+ from cells to maintain the cytoplasmic Na+ concentration. Until now, the ATPase involved in Na+ transport in cyanobacteria has not been characterized. Here, the characterization of ATPase and its role in Na+ transport of alkaliphilic halotolerant Aphanothece halophytica were investigated to understand the survival mechanism of A. halophytica under high salinity conditions.ResultsThe purified enzyme catalyzed the hydrolysis of ATP in the presence of Na+ but not K+, Li+ and Ca2+. The apparent Km values for Na+ and ATP were 2.0 and 1.2 mM, respectively. The enzyme is likely the F1F0-ATPase based on the usual subunit pattern and the protection against N,N'-dicyclohexylcarbodiimide inhibition of ATPase activity by Na+ in a pH-dependent manner. Proteoliposomes reconstituted with the purified enzyme could take up Na+ upon the addition of ATP. The apparent Km values for this uptake were 3.3 and 0.5 mM for Na+ and ATP, respectively. The mechanism of Na+ transport mediated by Na+-stimulated ATPase in A. halophytica was revealed. Using acridine orange as a probe, alkalization of the lumen of proteoliposomes reconstituted with Na+-stimulated ATPase was observed upon the addition of ATP with Na+ but not with K+, Li+ and Ca2+. The Na+- and ATP-dependent alkalization of the proteoliposome lumen was stimulated by carbonyl cyanide m - chlorophenylhydrazone (CCCP) but was inhibited by a permeant anion nitrate. The proteoliposomes showed both ATPase activity and ATP-dependent Na+ uptake activity. The uptake of Na+ was enhanced by CCCP and nitrate. On the other hand, both CCCP and nitrate were shown to dissipate the preformed electric potential generated by Na+-stimulated ATPase of the proteoliposomes.ConclusionThe data demonstrate that Na+-stimulated ATPase from A. halophytica, a likely member of F-type ATPase, functions as an electrogenic Na+ pump which transports only Na+ upon hydrolysis of ATP. A secondary event, Na+- and ATP-dependent H+ efflux from proteoliposomes, is driven by the electric potential generated by Na+-stimulated ATPase.

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Functional identification of electrogenic Na⁺‐translocating ATPase in the plasma membrane of the halotolerant microalga Dunaliella maritima

Cited by 26 publications

References 17 publications

Evolution of Plant P-Type ATPases

Evolution of Plant P-Type ATPases

Responses of photosynthetic apparatus of the halotolerant microalga Dunalliella maritima to hyperosmotic salt shock

Na+-stimulated ATPase of alkaliphilic halotolerant cyanobacterium Aphanothece halophytica translocates Na+ into proteoliposomes via Na+ uniport mechanism

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Functional identification of electrogenic Na+‐translocating ATPase in the plasma membrane of the halotolerant microalga Dunaliella maritima

Cited by 26 publications

References 17 publications

Evolution of Plant P-Type ATPases

Evolution of Plant P-Type ATPases

Responses of photosynthetic apparatus of the halotolerant microalga Dunalliella maritima to hyperosmotic salt shock

Na+-stimulated ATPase of alkaliphilic halotolerant cyanobacterium Aphanothece halophytica translocates Na+ into proteoliposomes via Na+ uniport mechanism

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Functional identification of electrogenic Na⁺‐translocating ATPase in the plasma membrane of the halotolerant microalga Dunaliella maritima