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

---

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

N-cadherin, a Ca(2+)-dependent cell adhesion molecule, has been localized previously to the mesoderm during chick gastrulation and to adherens junctions in beating avian hearts. However, a systematic study of the dynamic nature of N-cadherin localization in the critical early stages of heart development is lacking. The presented work defines the changes in the spatial and temporal expression of N-cadherin during early stages of chick heart development, principally between Hamburger and Hamilton stages 5-8, 18-29 hr of development. During gastrulation N-cadherin appears evenly distributed in the heart forming region. As development proceeds to form the pericardial coelom (stages 6, 7, and 8, i.e., between 22 and 26 hr of development) N-cadherin localization becomes restricted to the more central areas of the mesoderm. The localization also shows a periodicity that correlates closely with the distance between foci of cavities that eventually coalesce to form the coelom. This distribution suggests that N-cadherin may have a function in the sorting out of somatic and splanchnic mesoderm cells to form the coelom. This separation of the mesoderm in the embryo for the first time physically delineates the precardiac mesoderm population. Concomitant with cell sorting during coelom formation, the precardiac cells change shape and show a distinct polarity as conveyed by (1) the apical expression of N-cadherin on precardiac cell surfaces lining the pericardial coelom, (2) the primarily lateral expression of Na+,K(+)-ATPase, and (3) an enrichment of integrin (beta 1 subunit) on basal cell surfaces. The somatic mesoderm cells apparently down-regulate N-cadherin expression. N-cadherin is also absent from the precardiac cells close to the endoderm. The latter cells eventually form the endocardium, i.e., the endothelial lining of the heart. By contrast, in the tubular, beating heart N-cadherin is found throughout the myocardium. In summary, immunolocalization patterns of N-cadherin during early cardiogenesis suggest that this cell adhesion molecule has a major role in the dynamics of pericardial coelom formation. Subsequently, its continued expression during cell differentiation of the cardiomyocyte to form the myocardium, but not endocardium, suggests N-cadherin is an essential morphoregulatory molecule in heart organogenesis.
...
PMID:N-cadherin localization in early heart development and polar expression of Na+,K(+)-ATPase, and integrin during pericardial coelom formation and epithelialization of the differentiating myocardium. 131 97

Uvomorulin (E-cadherin), a cell adhesion molecule, and Na+,K(+)-adenosine triphosphatase (ATPase), a marker protein of the basal-lateral cell membrane domains of polarized epithelial cells, were investigated in a group of mouse skin tumors induced by a two-stage chemical carcinogenesis protocol and in cell lines derived from mouse skin papillomas and squamous cell carcinomas (SCC). Although these two markers were present in benign tumors and in nontumorigenic cell lines, the Na+,K(+)-ATPase showed an altered pattern of distribution that included the presence of enzyme not only in the basolateral domain but also on the apical domain of the cell membrane of basal and spinous cells in well-differentiated squamous cell carcinomas (SCC). In higher grade SCC, a loss of Na+,K(+)-ATPase immunoreactivity was simultaneously detected with a marginal or absent expression of uvomorulin. The more differentiated SCC and papillomas expressed less uvomorulin immunoreactivity than normal epidermal cells. Both markers were seen in tumor cell lines that produced well-differentiated SCC after subcutaneous inoculation into nude mice. Neither Na+,K(+)-ATPase nor uvomorulin could be detected in cell lines that produced high grade, poorly differentiated SCC. Northern blots confirmed the absence of uvomorulin mRNA in these highly malignant cell lines. These data indicate that progression from premalignant papilloma to low-grade SCC and subsequently to high-grade SCC is accompanied by loss of epithelial cell polarity as detected by changes in Na+,K(+)-ATPase and by decreased or absent expression of uvomorulin in tumors and cell lines characterized by an advanced malignant phenotype.
...
PMID:Alterations in the expression of uvomorulin and Na+,K(+)-adenosine triphosphatase during mouse skin tumor progression. 131 85

Vectorial function of polarized transporting epithelia requires the establishment and maintenance of a nonrandom distribution of Na,K-ATPase on the cell surface. In many epithelia, the Na,K-ATPase is located at the basal-lateral domain of the plasma membrane. The mechanisms involved in the spatial organization of the Na,K-ATPase in these cells are poorly understood. We have been investigating the roles of regulated cell-cell contacts and assembly of the membrane-cytoskeleton in the development of the cell surface polarity of Na,K-ATPase. We have shown that the Na,K-ATPase colocalizes with distinct components of the membrane-cytoskeleton in polarized Madin-Darby canine kidney (MDCK) epithelial cells. Significantly, we showed directly that Na,K-ATPase is a high affinity binding site for the membrane-cytoskeletal proteins ankyrin and fodrin, and that all three proteins exist in a high molecular weight protein complex that also contains the cell adhesion molecule (CAM) uvomorulin. We have proposed that these interactions are important in the assembly at sites of cell-cell contact of the membrane-cytoskeleton, which in turn initiates the development of the nonrandom distribution of the Na,K-ATPase. To directly investigate the functional significance of these protein-protein interactions in the spatial organization of the Na,K-ATPase, we analyzed the distribution of the Na,K-ATPase in fibroblasts transfected with a cDNA encoding the epithelial CAM, uvomorulin. Our results showed that expression of uvomorulin is sufficient to induce a redistribution of Na,K-ATPase from an unrestricted distribution over the entire cell surface in nontransfected cells to a restricted distribution at sites of uvomorulin-mediated cell-cell contacts in the transfected cells; this distribution is similar to that in polarized epithelial cells. This restricted distribution of the Na,K-ATPase occurred in the absence of tight junctions, but coincided with the reorganization of the membrane-cytoskeleton. These results support a model in which the epithelial CAM uvomorulin functions as an inducer of cell surface polarity of Na,K-ATPase through cytoplasmic linkage to the membrane-cytoskeleton.
...
PMID:Role of the membrane-cytoskeleton in the spatial organization of the Na,K-ATPase in polarized epithelial cells. 165 95

The generation of cell surface polarity in transporting epithelial cells occurs in three distinct stages that involve cell-cell recognition and adhesion, cell surface remodelling to form biochemically and functionally distinct cell surface domains, and development of vectorial function. A widely used model system to study mechanisms involved in these stages is the Madin-Darby canine kidney (MDCK) cell line. Under appropriate growth conditions, MDCK cells develop in similar stages into polarized, multicellular epithelial structures. Analysis of membrane-cytoskeletal proteins ankyrin and fodrin during development of MDCK cell surface polarity shows that they gradually assemble into an insoluble protein complex on the basal-lateral membrane domain upon cell-cell adhesion, concomitantly with the redistribution of Na+,K(+)-ATPase, a marker protein of the basal-lateral membrane. Biochemical analysis shows that ankyrin, fodrin occur in a complex with Na+,K(+)-ATPase and the cell adhesion molecule uvomorulin in MDCK cells. A model is presented in which assembly of membrane-cytoskeletal complexes at sites of uvomorulin-induced cell-cell contact causes a remodelling of the cell surface distribution of specific membrane proteins which, in turn, contributes to the generation of epithelial cell surface polarity.
...
PMID:Involvement of the membrane-cytoskeleton in development of epithelial cell polarity. 196 28

Cell-CAM 105 (C-CAM), a cell adhesion molecule in rat hepatocytes, was digested with trypsin, and peptides were isolated and sequenced by Edman degradation. The sequences of 4 peptides agreed with different regions of rat liver ecto-ATPase. Detailed biochemical analyses confirmed the identity between C-CAM and the ecto-ATPase. C-CAM/ecto-ATPase is a transmembrane protein having 4 immunoglobulin-like domains in the extracellular portion, demonstrating membership of the immunoglobulin superfamily. The ATPase activity suggests that ATP might influence cell adhesion, which would explain the inhibitory effect of exogenously added ATP on adhesion of several cell types.
...
PMID:The cell adhesion molecule Cell-CAM 105 is an ecto-ATPase and a member of the immunoglobulin superfamily. 214 77

Cell-cell contact is an important determinant in the formation of functionally distinct plasma membrane domains during the development of epithelial cell polarity. In cultures of Madin-Darby canine kidney (MDCK) epithelial cells, cell-cell contact induces the assembly and accumulation of the Na+,K+-ATPase and elements of the membrane-cytoskeleton (ankyrin and fodrin) at the regions of cell-cell contact. Epithelial cell-cell contact appears to be regulated by the cell adhesion molecule uvomorulin (E-cadherin) which also becomes localized at the lateral plasma membrane of polarized cells. We have sought to determine whether the colocalization of these proteins reflects direct molecular interactions which may play roles in coordinating cell-cell contact and the assembly of the basal-lateral domain of the plasma membrane. Recently, we identified a complex of proteins containing the Na+,K+-ATPase, ankyrin, and fodrin in extracts of whole MDCK cells (Nelson, W.J., and R. W. Hammerton. 1989. J. Cell Biol. 108:893-902). We have now examined cell extracts for protein complexes containing the cell adhesion molecule uvomorulin. Proteins were solubilized from whole MDCK cells and fractionated in sucrose gradients. The sedimentation profile of solubilized uvomorulin is well separated from the majority of cell surface proteins, suggesting that uvomorulin occurs in a protein complex. A distinct portion of uvomorulin (30%) cosediments with ankyrin and fodrin (approximately 10.5S). Further fractionation of cosedimenting proteins in nondenaturing polyacrylamide gels reveals a discrete band of proteins that binds antibodies specific for uvomorulin, Na+,K+-ATPase, ankyrin, and fodrin. Significantly, ankyrin and fodrin, but not Na+K+-ATPase, coimmunoprecipitate in a complex with uvomorulin using uvomorulin antibodies. This result indicates that separate complexes exist containing ankyrin and fodrin with either uvomorulin or Na+,K+-ATPase. These results are discussed in the context of the possible roles of uvomorulin-induced cell-cell contact in the assembly of the membrane-cytoskeleton and associated membrane proteins (e.g., Na+,K+-ATPase) at the contact zone and in the development of cell polarity.
...
PMID:Identification of a membrane-cytoskeletal complex containing the cell adhesion molecule uvomorulin (E-cadherin), ankyrin, and fodrin in Madin-Darby canine kidney epithelial cells. 215 83

The adhesion molecule on glia (AMOG) has been reported to function as cell adhesion molecule and also to constitute the beta 2-subunit of the murine Na,K-ATPase. In order to elucidate these functions in vivo, Magyar et al. have generated mice carrying a targeted deletion of the AMOG gene. These mice exhibit behaviourally normal development till postnatal day P16. At this time, they develop muscular weakness, incoordination, and tremor. Death invariably occurs 24-36 hours after onset of the symptoms. Histological and ultrastructural examination of brain sections show enlarged ventricles, brain edema, and swelling of astrocyte end feet. However, no disturbances of the architecture or cell migration in the brain can be detected. In order to identify long-term consequences of AMOG deficiency which might not yet be detectable at the time of death, we have established a CNS grafting model. The embryonal brain anlage (E10.5-E13.5) was grafted into the caudoputamen of wild type mice. The graft recipients are sacrificed up to 7 months after the procedure. Both wild type and AMOG deficient grafts develop and form solid neural tissue with neurons, myelinated axons, glial cells, and ventricular structures, as shown by histological and immunocytochemical analysis. However, no differences in grafts derived from wild type, heterozygous, and AMOG-deficient donors can be detected. Proliferation has been examined by BrdU immunocytochemistry. The blood-brain barrier as examined by repeated magnetic resonance imaging after injection of Gadolinium-DTPA has been shown to be largely reconstituted five weeks after grafting.
...
PMID:[Morphology and development of neural transplants of AMOG-deficient mice]. 753 17

The biogenesis of follicles from aggregates of precursor cells is an important morphogenetic process in thyroid embryology. It necessitates the creation of a polarized cell phenotype, assembly of specialized cell-cell junctions, and generation of follicular lumena. In this study we sought to investigate the relationship between cell polarization and lumen formation by studying the cell surface events that occurred when freshly isolated adult porcine thyroid cells reorganized to form follicles in primary culture. Follicular reorganization entailed the initial formation of solid three-dimensional cell aggregates and the subsequent appearance of lumena within aggregates. During the initial stage of cell aggregation, the adhesion molecule, E-cadherin, became expressed at all surfaces involved in cell-cell contact. Aggregation was inhibited by monoclonal antibodies that block cadherin function, indicating directly that E-cadherin is a dominant initial cell-cell adhesion molecule. Cell aggregation was also associated with the recruitment to the cell surface of ZO-1, a tight junction-associated protein, and Na+/K(+)-adenosine triphosphatase. These proteins were initially found throughout regions of cell-cell contact and only subsequently redistributed to their mature locations in tight junctions and the basolateral cell surface, respectively. In contrast, components associated with the apical membrane were first detected within large intracellular vacuoles, which subsequently fused with the cell surface between maturing tight junctions to yield the apical membrane domain and nascent follicular lumena. Follicle formation occurred independently of basal lamina assembly and TSH, although maintenance of follicular architecture required the presence of this hormone. These findings indicate that cultured follicles form in two distinct stages: 1) initial aggregation mediated by E-cadherin and associated with recruitment of components of both tight junctions and the basolateral membrane domain, and 2) subsequent formation of a specialized apical membrane domain by coordinated fusion of intracellular vacuoles at sites of the cell surface where tight junctions are maturing. We propose that follicular morphogenesis may arise as a consequence of epithelial cell polarization within coherent three-dimensional cell aggregates.
...
PMID:Cadherin-mediated adhesion and apical membrane assembly define distinct steps during thyroid epithelial polarization and lumen formation. 766 88

In the placenta the trophoblast cell layer separates maternal and fetal circulations and is involved in the active transport of selected substances across this barrier. We have used the JAR choriocarcinoma cell line to study aspects of trophoblast membrane transport. To determine whether JAR cells could be used in studies of vectorial transepithelial transport it was necessary to determine whether these cells were polarized and assembled tight junctions. In the present study we investigated JAR cells using a range of markers for specific cell surface domains combined with confocal laser scanning microscopy. Freshly isolated cells initially formed a confluent epithelial monolayer with recruitment of a tight junction-associated protein, ZO-1, and a cell adhesion molecule, E-cadherin, to the surface at sites of cell-cell contact. They did not, however, display cell surface polarization, as NaK-ATPase was not segregated in the basolateral domain, and a differentiated apical cell surface was not assembled. The monolayer stage was also unstable, as continued proliferation resulted in the formation of multilayered aggregates where ZO-1 and E-cadherin were lost from the cell surface. These results suggest that the JAR cell line is unlikely to be a suitable model for studies of transepithelial transport in the placenta.
...
PMID:Characterization of cell polarity and epithelial junctions in the choriocarcinoma cell line, JAR. 771 26

The rat liver ectoATPase has reportedly been cloned. The cDNA, a member of the carcinoembryonic antigen (CEA) gene family, was shown to increase aggregation of transfected cells, but ATPase activity was not evaluated. Using this cDNA as a probe to clone the mercurial-insensitive ectoATPase (MI-ectoATPase) of human hepatoma Li-7A cells, the cDNA obtained was that of CEA which has no ATPase activity. The probe also did not detect increased transcription when MI-ectoATPase activity was induced in Li-7A cells. It is concluded that the "rat liver ectoATPase cDNA" codes for a cell adhesion molecule but does not code for an ectoATPase. It was also discovered that expression of four CEA transcripts in Li-7A cells was markedly stimulated by a single growth modulator, EGF, and was further stimulated by a cAMP elevating agent, cholera toxin.
...
PMID:The rat liver ecto-ATPase/C-CAM cDNA detects induction of carcinoembryonic antigen but not the mercurial-insensitive ecto-ATPase in human hepatoma Li-7A cells treated by epidermal growth factor and cholera toxin. 786 39


1 2 3 Next >>

---