Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A primary function of cadherins is to regulate cell adhesion. Here, we demonstrate a broader function of cadherins in the differentiation of specialized epithelial cell phenotypes. In situ, the rat retinal pigment epithelium (RPE) forms cell-cell contacts within its monolayer, and at the apical membrane with the neural retina; Na+, K(+)-ATPase and the membrane cytoskeleton are restricted to the apical membrane. In vitro, RPE cells (RPE-J cell line) express an endogenous cadherin, form adherens junctions and a tight monolayer, but Na+,K(+)-ATPase is localized to both apical and basal-lateral membranes. Expression of E-cadherin in RPE-J cells results in restriction and accumulation of both Na+,K(+)-ATPase and the membrane cytoskeleton at the lateral membrane; these changes correlate with the synthesis of a different ankyrin isoform. In contrast to both RPE in situ and RPE-J cells that do not form desmosomes, E-cadherin expression in RPE-J cells induces accumulation of desmoglein mRNA, and assembly of desmosome-keratin complexes at cell-cell contacts. These results demonstrate that cadherins directly affect epithelial cell phenotype by remodeling the distributions of constitutively expressed proteins and by induced accumulation of specific proteins, which together lead to the generation of structurally and functionally distinct epithelial cell types.
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PMID:Plasticity in epithelial cell phenotype: modulation by expression of different cadherin cell adhesion molecules. 753 48

The renal proximal tubule is a major site of injury in a variety of congenital/metabolic diseases including nephropathic cystinosis, the most commonly known cause of renal Fanconi's syndrome. In this lysosomal storage disease there are defects in proximal tubule function within the first few months of life. While culture of renal tubular cells from the urine of these patients is possible, development of immortalized cell lines would insure large numbers of homogeneous cells for studies of renal epithelial cell morphology and pathophysiology in this disease. To develop immortalized cells, cystinotic and normal proximal tubular cells in culture were exposed to an immortalizing vector, containing pZiptsU19 with the temperature sensitive SV40 T-antigen allele tsA58U19 and a neomycin resistance gene, and neomycin-resistant tubular cells were selected for propagation. Ten clones from cystinotic patients have been developed and characterized. All clones express T-antigen at permissive temperature (33 degrees C). Immortalized cells have an epithelial morphology and grow to form confluent monolayers; doubling times vary from 31 to 86 hours. Cystinotic clones are keratin, MDR P-glycoprotein, and alpha-95 kD brush-border associated protein positive but Tamm-Horsfall protein negative by immunocytochemistry, as are normal proximal tubule cells immortalized with this vector. This is consistent with a proximal tubule origin of the cystinotic clones. The cystine content of the cystinotic cells is 70 to 160 times that of normal renal proximal tubular cells in culture, with most of the cystine sequestered in cell lysosomes, confirming that these cell lines express the storage defect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renal proximal tubular epithelium from patients with nephropathic cystinosis: immortalized cell lines as in vitro model systems. 756 23

Serum-free cultures of normal human buccal epithelial cells were transfected with a plasmid containing the SV40 T-antigen (SV40T) gene. Two major lines developed that showed extended lifespans (between 30 and 40 weeks) as compared with the controls (approximately 6 weeks). Continued growth through one or two crises generated several sublines. They expressed the epithelial marker keratin and also exhibited nuclear expression of SV40T. The lines showed abnormal karyotypes with both numerical and structural aberrations and variably responded to agents that normally inhibit growth and/or induce terminal differentiation, i.e. transforming growth factor-beta 1 and fetal bovine serum. One of the lines, termed SVpgC2a, developed into an apparently immortal line, since it had undergone more than 700 population doublings from over 2 years in culture. Further characterization of this line demonstrated its clonal origin, with integration of two copies of SV40T at the same site and the presence of both normal retinoblastoma and wild-type p53 proteins. This line showed high resistance to growth inhibition by transforming growth factor-beta 1 and serum similar to that shown by buccal carcinoma cell line SqCC/Y1. Neither SVpgC2a nor its parental lines were tumorigenic when injected into athymic nude mice, whereas the SqCC/Y1 cells induced tumors. The various lines with extended but finite lifespans, complemented by one immortalized line, which retained non-malignant properties upon extended culture, provide a battery of model systems that will be useful for studying mechanisms of human oral carcinogenesis.
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PMID:Characterization of human buccal epithelial cells transfected with the simian virus 40 T-antigen gene. 758 60

Epithelial-like cells from the colorectum of one-day-old newborn rats were immortalized by transfection with the simian virus 40 (SV40) T-antigen gene, and a cell line OUMS-25 was established. The cells were positive for the SV40 T-antigen, and immunoreactive to a colonic epithelial cell monoclonal antibody and a keratin-18 monoclonal antibody. Ultrastructural studies revealed the presence of microvilli on the cell surface and desmosomes between the adjacent cells. Karyotypic analysis showed that OUMS-25 cells were aneuploid. Cloning efficiency of the cells was 0.01% in soft agar. However, the cells were not tumorigenic in the syngeneic newborn rats. The cells were further transformed by transfection with the cloned activated c-Ha-ras oncogene containing a point mutation within codon 61. Characteristics of the activated-c-Ha-ras transfected cells (OUMS-25/RAS) were different in some respects from those of the parent cells (OUMS-25). OUMS-25/RAS cells demonstrated more malignant morphology, elevated cloning efficiency in soft agar, and tumorigenicity. This is the first report on the immortalization and malignant transformation of colorectal epithelial-like cells by transfection with a combination of SV40 T-antigen gene and cloned activated c-Ha-ras oncogene.
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PMID:Establishment and characterization of a SV40 T-antigen immortalized epithelial-like cell line derived from the newborn rat colorectum and its malignant transformation by the ras oncogene. 816 58

An enzymohistochemical and immunohistochemical study of the efferent ducts was performed in normal adult men. The epithelium consists of two types of columnar cells: principal cells (PCs) and ciliated cells (CCs), and is surrounded by a lamina propria (LP) with cells arranged circularly (LPCs). Enzymohistochemical study revealed more intense activity of succinic dehydrogenase, NADP, and ATPase in the CCs than in the PCs. The LPCs also showed an intense reaction for NADP and ATPase. Acid phosphatase activity was only intense in the apical cytoplasm of PCs. Immunohistochemical study revealed that antibodies to oestradiol receptor-related protein (ER-D5) immunostained the PCs and CCs intensely and the LPCs weakly. AE1/AE3 antibodies (which stain keratins nos. 1-8 and 14, 15 and 19) immunostained the PCs intensely, but was negative in both CCs and LPCs. Antibodies to keratin Ks.4.62 (which stain keratin no. 19) immunostained PCs and CCs but not LPCs. Epithelial membrane antigen antibodies (EMA) immunostained the adluminal surface and apical cytoplasm of PCs. Anti-vimentin antibodies immunostained the cytoplasm of PCs and CCs weakly as well as isolated cells in the LP. Antibodies to desmin immunostained most LPCs. Antibodies to collagen IV immunostained the basal lamina and many extracellular spaces in the LP, mainly around the LPCs. The differences between the enzymohistochemical and immunohistochemical patterns of the efferent ducts and those of the epididymis may help to explain functional differences along the epididymis.
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PMID:Enzymohistochemical and immunohistochemical study of the human efferent ducts. 827 25

We have previously cloned a cDNA encoding TBP-1, a protein present in the rat spermatid manchette and outer dense fibers of the developing sperm. TBP-1 contains a heptad repeat of six-leucine zipper fingers at the amino terminus and highly conserved ATPase and DNA/RNA helicase motifs toward the carboxyl terminus. TBP-1 is one of the 20 subunits forming the 19S regulatory complex of the 26S proteasome, an ATP-dependent multisubunit protease found in most eukaryotic cells. We now report the isolation of the 26S proteasome from rat testis and sperm tail and its visualization by whole-mount electron microscopy using negative staining. The 26S proteasome from rat testis was fractionated by Sephacryl S-400/Mono-Q chromatography using homogenates suspended in a 10% glycerol-supplemented buffer. Chromatographic fractions were analyzed by immunoblotting using a specific anti-TBP-1 serum. During the purification of Sak57, a keratin filament present in outer dense fibers from epididymal sperm, we detected a substantial amount of 26S proteasomes. Intact 26S proteasomes from rat testis display a rod-shaped particles about 45 nm in length and 11-17 nm in diameter. Each particle consists of a 20S barrel-shaped component formed by four rings (alphabetabetaalpha), capped by two polar 19S regulatory complexes, each identified by an element known as the "Chinese dragon head motif". TBP-1 is an ATPase-containing subunit of the 19S regulatory cap. Rat sperm preparations displayed both dissociated 26S proteasomes and Sak57 filaments. We hypothesize that 26S proteasomes in the perinuclear-arranged manchette are in a suitable location for recognition, sequestration, and degradation of accumulating ubiquitin-conjugated somatic and transient testis-specific histones during spermiogenesis. In the sperm tail, the 26S proteasome may have a role in the remodeling of the outer dense fibers and other tail components during epididymal transit.
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PMID:Structural features of the 26S proteasome complex isolated from rat testis and sperm tail. 1098 18

Our aim was to determine the molecular targets involved in the antiproliferative effects of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), in a normal murine mammary epithelial cell line, HC11. Among the early response genes analyzed, c-myc, junB, junD, c-jun, c-fos, fosB, fra, as well as max, mad1-4, sin3, only c-jun and fra-2 mRNAs were up-regulated after 1,25(OH)(2)D(3) exposure. Cyclin C was reduced and cyclin A2 and E were slightly enhanced; however, cyclins D1, D3, B1, B2, F, G1, G2, I and H, as well as TGF beta 1, TGF beta 3, T beta RI and T beta RII transcripts were not modulated by 1,25(OH)(2)D(3). Although p27(KIP1) protein content was unchanged, enhancement of p21(WAF1/CIP1) low basal levels in cell extracts and IGFBP-3 abundance on the culture medium was detected after 1,25(OH)(2)D(3) induction. Using differential display analysis, we identified eight down-modulated clones in exposed cells: 26S proteasome non-ATPase subunit Pad1, ubiquitin-conjugating enzyme Ube2i, extracellular proteinase inhibitor Expi or Wdnm1, cytochrome-c oxidase Cox7c, microtubule-associated protein-1 light chain-3 (Map1lc3), nascent-associated complex alpha Naca, transforming acidic coiled-coil Tacc3, stearoyl-CoA desaturase (Scd), keratin 6 alpha, and 1 up-regulated, fork head transcription factor Hfh-1L. Hence, the antiproliferative effect of 1,25(OH)(2)D(3) seems associated to enhancement of c-jun, Fra-2, IGFBP3 and p21(WAF1/CIP1). Decreased Pad1 and Ube2i might account for increased stability of cell cycle inhibitory proteins while reduced Wdnm1, Tacc3 and Scd might be secondary to accumulation of cells in G0/G1 phase.
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PMID:Molecular targets of 1,25(OH)2D3 in HC11 normal mouse mammary cell line. 1264 25

Trichophyton rubrum is a cosmopolitan and anthropophilic fungus able to invade keratinized tissue, causing infection in human skin and nails. This work evaluated the changes in the extracellular pH during its growth in keratin (after 6, 12, 24, 48, 72h and 7 days) at initial pH 5.0. We observed a gradual increase of basal pH under keratin exposure when compared to glucose condition. Also, we identified 576T. rubrum transcripts differentially expressed by subtractive suppression hybridization (SSH) using conidia cultivated for 72h in keratin as tester, and cultivated in glucose as driver. The over-expression of 238 transcripts obtained under keratin condition was confirmed by macro-array dot-blot, revealing 28 unigenes. Putative proteins encoded by these genes showed similarity to fungi proteins involved in basic metabolism, growth and virulence, i.e., transporters ABC-MDR, MFS and ATPase of copper, NIMA interactive protein, Gag-Pol polyprotein, virulence factors serine-protease subtilisin and metalloprotease, cytochrome P450, GlcN-6-phosphate deaminase and Hsp30. The upregulation of T. rubrum genes encoding subtilisin, metalloprotease and Gag-Pol polyprotein was also validated by northern blot. The results of this study provide the first insight into genes differentially expressed during T. rubrum grown in keratin that may be involved in fungal pathogenesis.
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PMID:Isolation of transcripts over-expressed in human pathogen Trichophyton rubrum during growth in keratin. 1759 Mar 7

Patients with acute respiratory distress syndrome and high-altitude pulmonary oedema build up excess lung fluid, which leads to alveolar hypoxia. In patients with acute respiratory distress syndrome and hypoxia, there is a decrease in oedema fluid clearance, due in part to the downregulation of plasma membrane sodium-potassium adenosine triphosphatase (Na,K-ATPase). In alveolar epithelial cells, acute hypoxia promotes Na,K-ATPase endocytosis from the plasma membrane to intracellular compartments, resulting in inhibition of Na,K-ATPase activity. Exposure to prolonged hypoxia leads to degradation of plasma membrane Na,K-ATPase. The downregulation of plasma membrane Na,K-ATPase reduces adenosine triphosphate demand, as part of a survival mechanism of cellular adaptation to hypoxia. Hypoxia has also been shown to disassemble and degrade the keratin intermediate filament network, a fundamental component of the cell cytoskeleton, affecting epithelial barrier function. Accordingly, better understanding of the mechanisms regulating cellular adaptation to hypoxia may lead to the development of novel therapeutic strategies for acute respiratory distress syndrome and high-altitude pulmonary oedema patients.
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PMID:Regulation of alveolar epithelial function by hypoxia. 1844 5

Trichophyton rubrum is a dermatophyte responsible for the majority of human superficial mycoses. The functional expression of proteins important for the initial step and the maintenance of the infection process were identified previously in T. rubrum by subtraction suppression hybridization after growth in the presence of keratin. In this study, sequences similar to genes encoding the multidrug-resistance ATP-binding cassette (ABC) transporter, copper ATPase, the major facilitator superfamily and a permease were isolated, and used in Northern blots to monitor the expression of the genes, which were upregulated in the presence of keratin. A sequence identical to the TruMDR2 gene, encoding an ABC transporter in T. rubrum, was isolated in these experiments, and examination of a T. rubrum DeltaTruMDR2 mutant showed a reduction in infecting activity, characterized by low growth on human nails compared with the wild-type strain. The high expression levels of transporter genes by T. rubrum in mimetic infection and the reduction in virulence of the DeltaTruMDR2 mutant in a disease model in vitro suggest that transporters are involved in T. rubrum pathogenicity.
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PMID:Membrane transporter proteins are involved in Trichophyton rubrum pathogenesis. 1914 31


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