Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The inhibition of glycolysis in tumor cells by methionine requires that the cells be incubated with methionine for several hours in the presence of serum. We now show that in the case of confluent rat-1 fibroblasts transfected with the ras gene the serum can be substituted by insulin and insulin-like growth factor I or II. No other growth factor tested was effective. In subconfluent ras cells additional growth factors (transferrin and high density lipoproteins) were required for maximal inhibition of glycolysis by methionine. Exploration of the mechanism of action of methionine revealed that the accumulation of [35S]methionine into rat-1 fibroblasts was only marginally increased by insulin. We propose that methionine inhibits an adenosine triphosphatase activity because addition of low concentrations of Nonidet P-40 greatly enhanced glycolysis even in the presence of methionine, suggesting that it did not affect the glycolytic enzymes directly. Methionine also affected growth both in monolayer and soft agar. Rat-1 fibroblasts transfected with the ras gene were markedly more sensitive to methionine than cells transfected with the myc gene.
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PMID:Effect of growth factors and methionine on glycolysis and methionine transport in rat fibroblasts and fibroblasts transfected with myc and ras genes. 308 Dec 58

In an initiation-promotion protocol, female weanling Sprague-Dawley rats were initiated with 10 mg/kg nitrosodiethylamine and promotion was started after 30 days. Promotion regimens were as follows: 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD; 150 ppt in diet) continuously until day 450; phenobarbital (PB; 500 ppm in diet) until day 170; PB until day 170, followed by TCDD until day 240; and PB until day 170, followed by a basal diet (BD) until day 240 and subsequently TCDD from days 240 to 450. TCDD fed to initiated rats had a promoting effect on the development of adenosine triphosphatase-negative altered hepatocellular foci (AHF). At 450 days, the volume fraction of liver occupied by AHF was increased in initiated rats given TCDD continuously and in those given PB followed by TCDD, whereas the mean volume of AHF was significantly larger in initiated rats given TCDD continuously. PB and TCDD promoted similar phenotypes of AHF as seen in hemotoxylin and eosin-stained sections, but the eosinophilic phenotype most closely correlated with the development of hepatocellular neoplasms. The protooncogene product ras p21 protein was present in the majority of PB- and TCDD-promoted AHF, hepatocellular adenomas, and hepatocellular carcinomas. Eosinophilic AHF and ras p21 protein expression most closely correlated with neoplastic development, suggesting that these cell populations, when promoted, may be at greater risks for developing into neoplasms.
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PMID:Tumor-promoting effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and phenobarbital in initiated weanling Sprague-Dawley rats: a quantitative, phenotypic, and ras p21 protein study. 781 18

The hepatitis C virus (HCV) nonstructural (NS) 3 protein has been shown to possess at least two enzymatic domains. The amino terminal third contains a serine-protease domain, whereas the carboxy terminal two thirds is comprised of an adenosine triphosphatase (ATPase)/helicase domain. These domains are essential for the maturation of the carboxy-terminal portion of the HCV polyprotein and catalyze the cap synthesis of the RNA genome. In this report, human and murine antibody responses induced by NS3 were characterized using a recombinant full-length NS3 (NS3-FL) protein, or the isolated protease or ATPase/ helicase domains, expressed and purified from Escherichia coli. Sera from 40 patients with chronic HCV infection were assayed in enzyme-linked immunoassays (EIAs) for antibody binding to the panel of NS3 proteins. Virtually all patient sera contained antibodies specific for NS3-FL and the ATPase/helicase domain, whereas only 10% of sera reacted with the protease domain of NS3. Human antibodies reactive with NS3-FL were highly restricted to the immunoglobulin G1 (IgG1) isotype and were inhibited by soluble ATPase/helicase, but not by the protease domain. The anti-NS3 (ATPase/helicase) reactivity decreased on denaturation by sodium dodecyl sulfate (SDS) and beta-mercaptoethanol (2ME), suggesting the recognition of nonlinear or conformational B-cell determinants. Similar to infected humans, mice immunized with NS3-FL developed high-titered primary antibody responses to the NS3 ATPase/ helicase domain, whereas an anti-NS3 protease response was not observed after primary or secondary immunizations. Thus, the human and murine humoral immune responses to the HCV NS3 protein are focused on the ATPase/helicase domain, are restricted to the IgG1 isotype in humans, and are conformationally dependent. Unexpectedly, in both species, the NS3 protease domain, present in the context of the full-length NS3, appears to possess low intrinsic immunogenicity in terms of antibody production.
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PMID:Human and murine antibody recognition is focused on the ATPase/helicase, but not the protease domain of the hepatitis C virus nonstructural 3 protein. 965 15

A rhodacyanine dye called MKT-077 has shown a highly selective toxicity toward several distinct human malignant cell lines, including bladder carcinoma EJ, and has been subjected to clinical trials for cancer therapy. In the pancreatic carcinoma cell line CRL-1420, but not in normal African green monkey kidney cell line CV-1, it is selectively accumulated in mitochondria. However, both the specific oncogenes responsible for its selective toxicity toward cancer cells, and its target proteins in these cancer cells, still remain to be determined. This study was conducted using normal and ras-transformed NIH 3T3 fibroblasts to determine whether oncogenic ras mutants such as v-Ha-ras are responsible for the selective toxicity of MKT-077 and also to identify its targets, using its derivative called "compound 1" as a specific ligand. We have found that v-Ha-ras is responsible for the selective toxicity of MKT-077 in both in vitro and in vivo. Furthermore, we have identified and affinity purified at least two distinct proteins of 45 kD (p45) and 75 kD (p75), which bind MKT-077 in v-Ha-ras-transformed cells but not in parental normal cells. Microsequencing analysis has revealed that the p45 is a mixture of beta- and gamma-actin, whereas the p75 is HSC70, a constitutive member of the Hsp70 heat shock adenosine triphosphatase family, which inactivates the tumor suppressor p53. MKT-077 binds actin directly, bundles actin filaments by cross-linking, and blocks membrane ruffling. Like a few F-actin-bundling proteins such as HS1, alpha-actinin, and vinculin as well as F-actin cappers such as tensin and chaetoglobosin K (CK), the F-actin-bundling drug MKT-077 suppresses ras transformation by blocking membrane ruffling. These findings suggest that other selective F-actin-bundling/capping compounds are also potentially useful for the chemotherapy of ras-associated cancers.
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PMID:Treatment of ras-induced cancers by the F-actin-bundling drug MKT-077. 1088 32

It has been shown that the Hepatitis C virus nonstructural NS3 protein possesses at least two enzymatic domains: a serine-protease domain and an adenosine triphosphatase (ATPase)/helicase domain. In this report, a truncated fragment of NS3 (26 kDa), representing main epitopes from the (ATPase)/helicase domain, has been expressed in Escherichia coli. The recombinant protein was purified by Ion Metal Affinity Chromatography (IMAC) with more than 90% purity. The recognition of B-cell linear epitopes in the NS3 protein was evaluated by immunoblot. The recombinant NS3 protein was reduced and carboxymethylated, and the recognition of either conformational and/or linear B-cell determinants was evaluated by ELISA. The inclusion of the recombinant NS3 protein in a third-generation diagnostic system UltraMicroELISA (UMELISA) allowed an increase in the sensitivity, due to the detection of a new variety of false-negative sera in blood donor test samples.
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PMID:Antigenicity of a recombinant NS3 protein representative of ATPase/helicase domain from hepatitis C virus. 1255 59

The protein-RNA interactions within the flavivirus replication complex (RC) are not fully understood. Our structure of dengue virus NS3 adenosine triphosphatase (ATPase)/helicase bound to the conserved 5' genomic RNA 5'-AGUUGUUAGUCU-3' reveals that D290 and R538 make specific interactions with G2 and G5 bases respectively. We show that single-stranded 12-mer RNA stimulates ATPase activity of NS3, however the presence of G2 and G5 leads to significantly higher activation. D290 is adjacent to the DEXH motif found in SF2 helicases like NS3 and interacts with R387, forming a molecular switch that activates the ATPase site upon RNA binding. Our structure guided mutagenesis revealed that disruption of D290-R387 interaction increases basal ATPase activity presumably as a result of higher conformational flexibility of the ATPase active site. Mutational studies also showed R538 plays a critical role in RNA interactions affecting translocation of viral RNA through dynamic interactions with bases at positions 4 and 5 of the ssRNA. Restriction of backbone flexibility around R538 through mutation of G540 to proline abolishes virus replication, indicating conformational flexibility around residue R538 is necessary for RNA translocation. The functionally critical sequence-specific contacts in NS3 RNA binding groove in subdomain III reveals potentially novel allosteric anti-viral drug targets.
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PMID:NS3 helicase from dengue virus specifically recognizes viral RNA sequence to ensure optimal replication. 2916 89