Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ectodermal cells of the two- and three-germ layer-thick mouse egg-cylinders are considered to be the progenitors of embryonal carcinoma cells in embryo-derived teratocarcinomas. In an attempt to find differences between the tumor cells and equivalent embryonic cells, we have studied the electron microscopic cytochemical localization of alkaline phosphatase, 5'-nucleotidase, and Mg2+-activated adenosine triphosphatase (ATPase) in embryo-derived teratocarcinomas and mouse egg-cylinders. Alkaline phosphatase was detected in both embryonic and tumor cells, but its activity appeared much more intense in the tumor cells. No ATPase was demonstrated in embryonic ectodermal cells of 6-day-old embryos and only in occasional cells of 7- and 8-day-old embryos. No 5'-nucleotidase activity could be demonstrated in 6- to 8-day-old cylinders. There was marked ATPase and 5'-nucleotidase activity in the membranes of embryonal carcinoma cells. These data point out some differences on the plasma membrane between the embryonal carcinoma cells and equivalent embryonic cells. The potential significance of these differences is discussed with regards to the transformation of embryonic cells in tumor cells. (Am J Pathol 87:297-310, 1977).
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PMID:Ultrastructural localization of membrane phosphatases in teratocarcinoma and early embryos. 19 83

Murine embryonal carcinoma cells (EC) can be induced to differentiate by a variety of chemical agents, including retinoid acid (RA) and dimethyl acetamide (DMA). However, it is not known how these agents exert their effects. In this study we demonstrate that murine EC cells can also be induced to differentiate by ouabain at concentrations which inhibit Na+, K+-ATPase activity as measured by inhibition of 86Rb+ uptake. Since the pharmacologic action of ouabain is thought to be specific, we investigated the role of Na+, K+-ATPase inhibition and specific metabolic consequences of this inhibition in the induction of EC differentiation, and explored whether this might be a common mode of action for a variety of structurally diverse inducers. Although the Na+, K+-ATPase maintains ion gradients in cells, our studies failed to demonstrate a consistent role for alterations of ion flux or ion concentration on the differentiation process. Ouabain inhibited cell growth, but a direct correlation between the degree of growth inhibition and the extent of differentiation could not be demonstrated. There was also no evidence that RA or DMA induces differentiation by inhibiting the Na+, K+-ATPase. The mechanism of ouabain induction may be mediated by some alternative consequence of Na+, K+-ATPase inhibition, but it appears to be specific for that inducer and cannot be generalized to that of other inducers of EC differentiation.
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PMID:Induction of differentiation of murine embryonal carcinoma cells by ouabain. 283 55

The limitations to SV40 growth in nonpermissive cells are poorly understood. In differentiated mouse cells, early mRNA and T-antigens are synthesized, but no viral DNA replication has been detected. A plausible explanation for the limitation to viral DNA synthesis in these cells might be the inability of a mouse cell-specific DNA polymerase to interact with the SV40 T-antigen-viral DNA complex. In spite of this abortive viral-cell interaction, SV40 late viral transcripts can be detected in infected mouse cells. Both early and late transcripts can be detected in infected mouse cells. Both early and late SV40 transcriptional activities peak between 10 and 15 h post infection; by 24 h after infection SV40 RNA is almost undetectable. In spite of the detection of late SV40 mRNA in mouse cells, we have been unable to detect any structural proteins (VP1, VP2, or VP3) encoded by these transcripts. A more restrictive interaction occurs between SV40 and undifferentiated mouse teratocarcinoma cell lines. Using an in vitro technique, the viral transcriptional complex (VTC) assay, we were able to demonstrate viral transcriptional activity on both the early and the late strands of SV40 in F9 embryonal carcinoma cells. Nevertheless, no mature processed mRNAs or viral encoded polypeptides were detected in these cells. After differentiation of the F9 cells with retinoic acid, however, spliced early mRNAs, as well as the SV40 T-antigen, were present.
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PMID:The regulation of SV40 gene expression in nonpermissive cells. 627 31

Adeno-associated virus (AAV) type 2 Rep78 is a multifunctional protein required for AAV DNA replication, integration, and gene regulation. The biochemical activities of Rep78 have been described, but the effects of Rep proteins on the cell have not been characterized. We have analyzed Rep-mediated cytotoxicity. We demonstrated that Rep78 expression is sufficient to induce cell death and disruption of the cell cycle. Cell death was found to be mediated by apoptosis. Rep78 expression resulted in the activation of caspase-3, a terminal caspase directly involved in the execution of cell death. A peptidic inhibitor of caspase-3, Z-Asp-Glu-Val-Asp-fluoromethylketone (Z-DEVD-FMK), abrogated Rep78-induced apoptosis, indicating that Rep78-mediated apoptosis is caspase-3 dependent. Rep78 induced apoptosis in wild-type p53-containing human embryonal carcinoma NT-2 cells and in p53-null promyelocytic human HL-60 cells, indicating that at least one pathway of Rep78-induced apoptosis is p53 independent. Apoptosis was shown to occur during the G(1) and early S phases of the cell cycle. By analyzing the effects of Rep78 mutations on cell viability, the cause of cell death was attributed in part to two biochemical activities of Rep78, DNA binding and ATPase/helicase activity. The endonuclease activity of Rep78 did not contribute to apoptosis induction.
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PMID:Adeno-associated virus type 2 Rep78 induces apoptosis through caspase activation independently of p53. 1100 Feb 13

The yeast SWI/SNF complex is involved in remodeling of chromatin structure during transcriptional modulation. One of the key subunits of this complex, called SWI2/SNF2, has a DNA-dependent ATPase activity. Two different types of mammalian homolog of yeast SWI2/SNF2, called BRM and BRG1, were recently identified. They are closely similar in structure but have distinct functions. We investigated the expression of BRM and BRG1 during differentiation of neural precursor cells (NPCs) cultured in vitro. The expression of BRM was very low in NPCs and was induced to a high level during differentiation to neurons and astrocytes. In contrast, BRG1 was constantly expressed throughout differentiation. These phenomena were also observed in differentiation of P19 embryonal carcinoma cells to neural cells. Immunocytochemical analyses revealed that the expression of BRM started even in the undifferentiated nestin-positive cells. These results indicate that BRM may have an important role in neural cell differentiation.
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PMID:Expression of chromatin remodeling factors during neural differentiation. 1113 56