Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Proton-Translocating ATPases”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

Adenosine triphosphate in the bovine chromaffin granule.

1. pH and potential gradients are generated across the membranes of chromaffin granule 'ghost' by incubating them with MgATP: the inside of the 'ghosts' is positive and acid with respect to the incubation medium. 2. The pH gradient is partially dissipated by inclusion of a substrate for the catecholamine pump, or a mitochondrial uncoupling agent, but is enhanced by reserpine. 3. An imposed pH gradient leads to amine uptake by the 'ghosts': a potential gradient leads to ATP uptake. Studies with inhibitors confirm that amine accumulation by chromaffin granules is dependent on the former, and that ATP uptake results from ATPase-induced potential difference generation. 4. ATP has two known roles in chromaffin granule structure: the first is as a substrate for a membrane-bound proton-translocating ATPase; the second is as a component of the intragranular catecholamine storage complex.

Adenosine Triphosphate↗
PubMed1978

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

ATP-driven transport and accumulation of epinephrine in chromaffin granule membrane vesicles isolated from bovine adrenal medulla is inhibited by the proton ionophores carbonylcyanide p-trifluoromethoxyphenylhydrazone and nigericin, but not by valinomycin. Moreover, an artificially imposed pH gradient (interior acid) is able to drive this reserpine-sensitive transport system in the absence of ATP. Dicyclohexylcarbodiimide, an inactivator of the chromaffin granule membrane-bound ATPase, completely inhibits ATP-dependent epinephrine accumulation, but has much less effect when an imposed pH gradient is the driving force for epinephrine transport. The findings provide a strong indication that a pH gradient (interior acid) is the immediate driving force for epinephrine uptake in these storage granules and suggest that ATP-driven epinephrine transport is the result of two processes: (i) generation of a proton electrochemical gradient (interior acid and positive) by the membrane-bound, proton-translocating ATPase; and (ii) pH gradient-driven accumulation of the catecholamine.

Animals↗
PubMed2026

Genomic and structural insights into the atpB L173I substitution: modulation of the F₀ rotor architecture in Mycobacterium tuberculosis ATP synthase and altered Bedaquiline binding dynamics.

The F₀F₁ ATP synthase of Mycobacterium tuberculosis (M. tuberculosis) is an essential membrane-embedded rotary motor responsible for ATP synthesis and maintenance of the proton motive force in bacteria. The transmembrane F₀ domain comprises the c-subunit (atpE) and the a-subunit (atpB). Their coordinated interactions are needed for proton translocation and torque generation. Bedaquiline (BDQ), FDA-approved diarylquinoline for the treatment of multidrug-resistant tuberculosis (MDR-TB), targets the F₀ motor by binding at the a-c interface and inhibiting rotary catalysis. To the best of our knowledge, this study represents the first attempt to analyze the effects of mutations in the atpB protein on its structural stability in the F₀ domain, thereby highlighting the novelty of this work. In this study, we integrated Indian whole-genome sequencing (WGS) datasets (PRJNA37907) with long-timescale (1000 ns) membrane-embedded molecular dynamics (MD) simulations. Among 57 atpB mutations identified from WGS analysis, L173I was selected for structural and MD analysis. L173I is located at the atpB-atpE interface near the BDQ-binding region, despite V177L and S184A showing higher prevalence. Comparative MD simulations encompassed four systems: wild-type apo, wild-type with BDQ, L173I apo, and L173I with BDQ. Structural interrogation revealed that the L173I substitution induces subtle destabilization of the global fold of the atpB-atpE complex relative to the apo state, while more critically attenuating inter-subunit contacts between the a-subunit and the c-ring. These perturbations provide a mechanistic rationale for reduced BDQ susceptibility, arising from altered interfacial dynamics rather than complete abrogation of drug binding. This integrative genomic-structural framework advances our understanding of ATP synthase-mediated resistance in M. tuberculosis.

Diarylquinolines↗
PubMed2004

Function-informed transcriptome analysis of Drosophila renal tubule.

BACKGROUND: Comprehensive, tissue-specific, microarray analysis is a potent tool for the identification of tightly defined expression patterns that might be missed in whole-organism scans. We applied such an analysis to Drosophila melanogaster Malpighian (renal) tubule, a defined differentiated tissue. RESULTS: The transcriptome of the D. melanogaster Malpighian tubule is highly reproducible and significantly different from that obtained from whole-organism arrays. More than 200 genes are more than 10-fold enriched and over 1,000 are significantly enriched. Of the top 200 genes, only 18 have previously been named, and only 45% have even estimates of function. In addition, 30 transcription factors, not previously implicated in tubule development, are shown to be enriched in adult tubule, and their expression patterns respect precisely the domains and cell types previously identified by enhancer trapping. Of Drosophila genes with close human disease homologs, 50 are enriched threefold or more, and eight enriched 10-fold or more, in tubule. Intriguingly, several of these diseases have human renal phenotypes, implying close conservation of renal function across 400 million years of divergent evolution. CONCLUSIONS: From those genes that are identifiable, a radically new view of the function of the tubule, emphasizing solute transport rather than fluid secretion, can be obtained. The results illustrate the phenotype gap: historically, the effort expended on a model organism has tended to concentrate on a relatively small set of processes, rather than on the spread of genes in the genome.

Animals↗
PubMed2026

A single small molecule-based human embryo model reveals V-ATPase requirement in mammalian blastocyst cavitation.

Human naïve pluripotent stem cells (nPSCs) can be induced by various combinations of signaling factors to generate blastocyst-like structures, termed blastoids. Despite rapid progress in human blastoid models, their potential to uncover fundamental mechanisms of early human development remains limited, leaving key morphogenetic processes poorly understood. Here, we describe a simple and robust system in which dimethyl sulfoxide (DMSO) alone induces blastoid formation from human nPSCs. This model recapitulates key pre- and post-implantation features and exhibits enhanced polar trophectoderm (TE) organization, more efficient attachment within an implantation-relevant window, improved epiblast lumenogenesis associated with amniotic cavity formation, and more robust, sustained expansion of embryonic lineages following attachment. Using this system, we reveal a previously unrecognized mechanism underlying TE cavitation and identify lysosome-associated genes - particularly subunits of the proton pump V-ATPase - as essential regulators of blastoid cavitation. DMSO treatment upregulates key V-ATPase subunits (ATP6V0A4 and ATP6V1B1), which are also enriched in the TE of human embryos. Genetic or pharmacological inhibition of V-ATPase activity disrupts lysosomal acidification, blocks intracellular vacuole formation, and impairs blastoid cavitation, whereas overexpression of V-ATPase subunits rescues this phenotype. Furthermore, genetic and pharmacological perturbations of V-ATPase function significantly compromise cavitation in both mouse and human blastocysts. Finally, DMSO treatment induces membrane biomechanical changes characteristic of early embryonic development, suggesting a mode of action distinct from conventional small-molecule, signaling pathway-based induction strategies. This simple DMSO-based blastoid model recapitulates key aspects of human blastocyst development and reveals a conserved requirement for V-ATPase-mediated lysosomal acidification during early mammalian embryogenesis.

Humans↗
PubMed2025

TCF25 serves as a nutrient sensor to orchestrate metabolic adaptation and cell death by enhancing lysosomal acidification under glucose starvation.

Cells adapt to nutrient limitation by activating catabolic and inhibiting anabolic pathways, yet prolonged stress may lead to cell death. How cells orchestrate metabolic adaptation and cell death to nutrient stress is poorly understood. We conduct a genome-wide CRISPR-Cas9 screen to identify regulators in glucose-starvation-induced cell death and find a group of genes in lysosomal pathway is enriched following glucose starvation. We focus on one candidate gene, Transcriptional Factor 25 (TCF25). We find TCF25 enhances lysosomal acidification by targeting V-ATPase, promoting autophagy and ATP generation under glucose starvation. However, prolonged glucose starvation constitutively activates ferritinophagy via TCF25, increasing lysosomal membrane permeability (LMP) and leading to lysosome-dependent cell death (LDCD). Knocking out TCF25 or V-ATPase components prevents cell death. Furthermore, TCF25 deficiency protects mice from hepatic ischemia-reperfusion injury. Our findings identify TCF25 as a crucial nutrient sensor that regulates lysosomal activity, offering potential therapeutic targets for metabolic and ischemic disorders.

Lysosomes↗
PubMed2026

Whole exome sequencing identifies three novel variants and establishes the molecular diagnosis of ATP6V0A4-related distal renal tubular acidosis in a lebanese infant.

BACKGROUND: Distal renal tubular acidosis (dRTA) is a rare inherited disorder characterized by impaired urinary acidification, leading to metabolic acidosis, hypokalemia, nephrocalcinosis, and growth impairment. Pathogenic variants in ATP6V0A4 are among the most common genetic causes of autosomal recessive dRTA. METHODS AND RESULTS: We report a Lebanese infant presenting with failure to thrive, recurrent vomiting, severe hyperchloremic metabolic acidosis, hypokalemia, and bilateral nephrocalcinosis, in whom whole-exome sequencing (WES) was performed to establish the molecular diagnosis and perform a comprehensive genomic evaluation. WES identified three novel variants, including a novel homozygous likely pathogenic ATP6V0A4 variant, consistent with the patient's phenotype. Two additional novel variants in TTN and CEP290 were also detected. Family segregation analysis confirmed the inheritance pattern of all three variants and refined the interpretation of the additional genomic findings. The patient showed sustained clinical and biochemical improvement to alkali therapy, with normalization of biochemical abnormalities and improvement in growth during follow-up. CONCLUSIONS: This report expands the molecular spectrum of ATP6V0A4-related dRTA and illustrates the clinical utility of comprehensive WES combined with segregation analysis for accurate molecular diagnosis, variant interpretation, genetic counseling, and the evaluation of additional genomic findings in rare inherited disorders.

Humans↗
PubMed1977

Gated proton conduction via the coupling factor of photophosphorylation modified by N,-N-orthophenyldimaleimide.

The membrane bound coupling factor of photophosphorylation is studied after pretreatment of broken chloroplasts with the bifunctional N,N-orthophenyldimaleimide under energization of the thylakoid membrane by mild flashing light. The proton conduction of the membrane is monitored both via the electrochromic absorption changes and via selective pH-indicating dyes. It is found that the coupling factor, after interaction with N,N-orthophenyldimaleimide during the preillumination period, shortcircuits one of the two protons pumped inside after excitation of chloroplasts with one short flash of light. In contrast to the low proton conductivity of the unperturbed thylakoid membrane (relaxation time for a proton gradient greater than 5s), this extra proton channel leads to a partial relaxation of a proton gradient within a few ms. Although limited to only one proton per electron, this extra proton conducting pathway is not otherwise specific. It operates with protons resulting from both Photosystem I and Photosystem II activity. In addition it operates with protons already present in the internal phase before firing of the exciting light flash. These effects are prevented by the presence of ATP (but not GTP) during the preillumination period. It is suggested that the modified coupling factor is gated open by the light induced electric field across the thylakoid membrane while self closing after passage of one proton per activated coupling factor.

Chemical Phenomena↗
PubMed1978

Synthesis and hydrolysis of ATP by intact chloroplasts under flash illumination and in darkness.

ATP concentrations were measured in isolated intact spinach chloroplasts under various light and dark conditions. The following results were obtained: (1) Even in darkened chloroplasts and in the absence of exogenous substrates, ATP levels in the chloroplast stroma were significant. They decreased on addition of glycerate, phosphoglycerate or dihydroxyacetone phosphate. When dihydroxyacetone phosphate and oxaloacetate were added together, ATP levels increased in darkened chloroplasts owing to substrate level phosphorylation. (2) Under illumination with saturating single turnover flashes, oxygen evolution in the presence of phosphoglycerate, whose reduction requires ATP, was no lower on a unit flash basis at the low flash frequency of 2 Hz than at higher frequencies. Quenching of 9-aminoacridine fluorescence, which indicates the formation of a proton gradient in intact chloroplasts, decreased with decreasing flash frequencies, until there was no significant fluorescence quenching at a flash frequency of about 2 Hz. In contrast to intact chloroplasts, broken chloroplasts did not phosphorylate much ADP at the low flash frequency of 2 Hz. (3) Flashing at extremely low frequencies (0.2 Hz) caused ATP hydrolysis rather than ATP synthesis in intact chloroplasts. At higher flash frequencies, synthesis replaced hydrolysis. Still, even at high frequencies (10 Hz), the first flashes of a series of flashes given after a long dark time always decreased chloroplast ATP levels. From these results, it is concluded that the enzyme, which mediates ATP synthesis in the light, is inactive in darkened intact chloroplasts. Its light activation can be separated from the formation of the high energy condition, which results in ATP synthesis. After its activation, the enzyme catalyzes a reversible reaction.

Adenosine Diphosphate↗
PubMed2025

Dominant negative ATP5F1A variants disrupt oxidative phosphorylation causing neurological disorders.

ATP5F1A encodes the α-subunit of complex V of the respiratory chain, which is responsible for mitochondrial ATP synthesis. We describe 6 probands with heterozygous de novo missense ATP5F1A variants that presented with developmental delay, intellectual disability, and movement disorders. All variants were located at the contact points between the α- and β-subunits. Functional studies in C. elegans revealed that the variants were damaging via a dominant negative genetic mechanism. Biochemical and proteomics studies of proband-derived cells showed a marked reduction in complex V abundance and activity. Mitochondrial physiology studies revealed increased oxygen consumption, yet decreased mitochondrial membrane potential and ATP levels indicative of uncoupled oxidative phosphorylation as a pathophysiologic mechanism. Our findings contrast with the previously reported ATP5F1A variant, p.Arg207His, indicating a different pathological mechanism. This study expands the phenotypic and genotypic spectrum of ATP5F1A-associated conditions and highlights how functional studies can provide an understanding of the genetic, molecular, and cellular mechanisms of ATP5F1A variants of uncertain significance. With 12 heterozygous individuals now reported, ATP5F1A is the most frequent nuclear genome cause of complex V deficiency.

Humans↗
PubMed1978

[Stimulation mechanism of soluble ATPase from chloroplasts (CF1)].

Effects of various compounds on Mg-dependent ATPase activity of chloroplast coupling factor--CF1--were studied. It was shown that the stimulating effect of compounds is increased with the increase in their hydrophobicity. Under given experimental conditions all compounds under study readily accept and donate protons. The maximal efficiency is reached when pH of the medium is close to the pK value of conjugated acid. It is assumed that the stimulating effects of compounds on Mg-dependent chloroplast ATPase consist in the increase of the rate of the limiting step of enzyme induced proton translocation coupled to the catalytic step of ATP hydrolysis.

2,2'-Dipyridyl↗
PubMed1979

The proton-translocating adenosine triphosphatase of the obligately anaerobic bacterium Clostridium pasteurianum. 1. ATP phosphohydrolase activity.

1. The cell-membrane ATP phosphohydrolase of vegetatively grown Clostridium pasteurianum was specifically Mg2+-dependent, but demonstrated significant activity with GTP, CTP and UTP. It displayed approximate Michaelis-Menten kinetics only in the presence of certain effectors (e.g. phosphoenolpyruvate, fructose 1,6-bis-phosphate) which decreased the Km for ATP (to below 2 mM) but also V, whilst extending to pH 5.8 the effective pH range of activity of the enzyme. 2. ATP phosphohydrolase activity of the membrane ATPase (BF0F1) was inhibited by N,N'-dicyclohexylcarbodiimide, butyricin 7423, Dio-9, 4-chloro-7-nitrobenzofurazan, efrapeptin, leucinostatin and quercetin, and to a lesser degree by aurovertin and citreoviridin. The enzyme was not inhibited by oligomycin, spegazzinine, tributyl tin, triethyl tin or venturicidin. The soluble ATPase (BF1) component differed in not being inhibited by N,N'-dicyclohexylcarbodiimide, butyricin 7423 or leucinostatin. 3. The ATPase (BF0F1) complex and its soluble (BF1) component were separately purified. 4. Dodecylsulphate/polyacrylamide gel electrophoresis separated only four polypeptide components in the purified ATPase (BF0F1), with approximate molecular weights (+/- 10%) as follows: subunit a, 65 500; subunit c, 57 500; subunit da, 43 000; subunit fa, 15 000. The soluble (BF1 component contained only the three polypeptide subunits a, c and da. These were present in the BF0F1 preparation in the ratio 2 : 1 : 2; the contribution of subunit fa could not satisfactorily be quantified. 5. Subunit a was identified as the component binding 4-chloro-7-nitrobenzofurazan and subunit fa as the component binding N,N'-dicyclohexylcarbodiimide. The ATP phosphohydrolase activity of the membrane ATPase was not activated by trypsin treatment and the ATPase (BF0F1) contained no trypsin-sensitive inhibitor protein subunit. 6. Purified ATPase (BF0F1) was incorporated into artificial proteoliposomes which demonstrated ATP-dependent enhancement of 8-anilinonaphthalene-1-sulphonate fluorescence and ATP-dependent proton influx. These reactions were abolished by proton conductors (e.g. carbonylcyanide m-chlorophenylhydrazone) by valinomycin in the presence of a high external concentration of K+, or by N,N'-dicyclohexylcarbodiimide, butyricin 7423, Dio-9, 4-chloro-7-nitrobenzofurazan or leucinostatin. Oligomycin, tributyl tin, triethyl tin and venturicidin were not inhibitory. 7. When stripped of the soluble BF1 component, such ATPase-proteoliposomes demonstrated nil ATP phosphohydrolase activity and did not display ATP-dependent enhancement of 8-anilino-naphthalene-1-sulphonate fluorescence or ATP-dependent protein influx. All of these activities were restored by incubation of the BF1-depleted proteoliposomes with a purified preparation of the soluble BF1 component.

Adenosine Triphosphatases↗