Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. We performed an enzymatic characterization of two different fractionation procedures of ventricles from rat hearts. The enzymatic assays covered succinic dehydrogenase as a marker for inner mitochondrial membranes, monoamine oxidase as a marker for outer mitochondrial membranes, NADPH-cytochrome c reductase and RNA as endoplasmatic reticular markers, acid phosphatase as a lysosomal marker, and lactic dehydrogenase as a marker for the "soluble" compartment; DNA was estimated for nuclear contamination. 2. The plasma membrane markers 5'-nucleotidase, Ca2+-ATPase, Mg2+-ATPase, Na+-K+-ATPase, and adenylate cyclase were determined. 3. The roughly prepared membrane fractions showed increased yields of the membrane markers; the number of beta receptors, determined with (-)-[3H] dihydroalprenolol and DL-propranolol, amounted to 68 +/- 6 fmol/mg protein (KD = 3390 +/- 450 pmol, Hill coefficient = 1.5). 4. The membrane fraction prepared with a linear sucrose gradient showed an increased inner mitochondrial membrane marker; presumably the outer mitochondrial membrane was stripped off. The beta-receptor number was 39 +/- 3 fmol/mg protein (KD = 6250 +/- 300 pmol; Hill coefficient = 1.2).
Cell Mol Neurobiol 1988 Jun
PMID:Beta-adrenergic receptors and enzymes in rat myocardial membranes: implications of fractionation procedures and beta-adrenoceptor antagonists. 284 52

Highly purified preparations of plasma membranes from control and ketoconazole-treated (1 microM, 120 h) epimastigotes of Trypanosoma cruzi have been obtained by cell disruption using abrasion with glass beads, differential centrifugation and isopycnic centrifugation in continuous, self-generating Percoll gradients. The purity of the preparation was ascertained by the specific activity 125I bound to the membranes obtained from enzymatically radiolabeled epimastigotes and by the alpha-methyl-mannoside sensitive binding of 125I-concanavalin A. The membranes form closed vesicles of 0.2-0.4 micron in diameter which display Mg2+ ATPase and acid phosphatase activities, but are devoid of 5'-nucleotidase and succinate-cytochrome c oxidoreductase; these vesicles can be strongly agglutinated by concanavalin A. The lipid order profiles of membranes from control and treated cells were compared with that present in egg phosphatidylcholine/ergosterol liposomes (84:16, mol/mol) by electron spin resonance spectroscopy of doxylstearic acid probes with the nitroxide group bound to carbon 5, 10, 12 and 16 of the stearic acid chain. Membranes from treated epimastigotes have a lipid order profile which resembles that of control plasma membranes near the polar surface (positions 5 and 10) but there is an abrupt decrease of order at position 12 and from there to the center of bilayer is highly disordered, even more than in pure lipid membranes. Consistent with these results, the leakage of L-[14C]glucose from membrane vesicles of ketoconazole-treated cells is much faster than that observed in vesicles obtained from control cells. These results indicate a strong alteration of the plasma membrane physical and biological properties due to the incubation of the parasite with the drug; this alteration is consistent with the accumulation of methylated precursors of ergosterol, which affects both lipid-lipid and lipid-protein interactions in the membrane.
Mol Biochem Parasitol 1988 Aug
PMID:Alteration of lipid order profile and permeability of plasma membranes from Trypanosoma cruzi epimastigotes grown in the presence of ketoconazole. 284 68

Human prostatic acid phosphatase (PAcP) has been found to have phosphotyrosyl-protein phosphatase activity (H. C. Li, J. Chernoff, L. B. Chen, and A. Kirschonbaun, Eur. J. Biochem. 138:45-51, 1984; M.-F. Lin and G. M. Clinton, Biochem. J. 235:351-357, 1986) and has been suggested to negatively regulate phosphotyrosine levels, at least in part, by inhibition of tyrosine protein kinase activity (M.-F. Lin and G. M. Clinton, Adv. Protein Phosphatases 4:199-228, 1987; M.-F. Lin, C. L. Lee, and G. M. Clinton, Mol. Cell. Biol. 6:4753-4757, 1986). We investigated the molecular interaction of PAcP with a specific tyrosine kinase, the epidermal growth factor (EGF) receptor, from prostate carcinoma cells. Of several proteins phosphorylated in membrane vesicles from prostate carcinoma cells, PAcP selectively dephosphorylated the EGF receptor. The prostate EGF receptor was more efficiently dephosphorylated by PAcP than by another phosphotyrosyl phosphatase, potato acid phosphatase. Further characterization of the interaction of PAcP with the EGF receptor revealed that the optimal rate of dephosphorylation occurred at neutral rather than at acid pH. Thus, the enzyme that we formerly referred to as PAcP we now call prostatic phosphotyrosyl-protein phosphatase. Hydrolysis of phosphate from tyrosine residues in the immunoprecipitated EGF receptor catalyzed by purified prostatic phosphotyrosyl-protein phosphatase caused a 40 to 50% decrease in the receptor tyrosine kinase activity with angiotensin as the substrate. In contrast, autophosphorylation of the receptor was associated with an increase in tyrosine kinase activity.
Mol Cell Biol 1988 Dec
PMID:The epidermal growth factor receptor from prostate cells is dephosphorylated by a prostate-specific phosphotyrosyl phosphatase. 285 98

Fine structural aspects of the effect of minocycline, an antibiotic of the tetracycline group, on the rat thyroid were studied. In all the rats administered minocycline (100 mg/kg/day) for 21 days, diffuse black discoloration of the thyroid gland occurred. However, when the rats were fed on a low iodine diet, given propylthiouracil (PTU) or thyroxine tablet with minocycline the black pigmentation of the thyroid gland did not take place. On the other hand, black discoloration of the thyroid was accelerated in the rats administered TSH and minocycline simultaneously. Ultrastructurally, numerous dense bodies containing highly electron-dense deposits were seen in the supranuclear region of the follicular epithelial cells of the black thyroid. These dense bodies, which showed positive acid phosphatase activity, are considered to be lysosomes containing minocycline or its derivatives. It is speculated that minocycline is taken up into follicular epithelial cells with iodine, and that the black discoloration of the thyroid gland is intimately related to iodine metabolism.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Fine structural aspects of the black thyroid induced by minocycline, and the effects of a low iodine diet, propylthiouracil, thyroxine tablet and TSH, on the black discoloration of the rat thyroid. 285 95

In earlier studies we investigated the in vivo effects of lipopolysaccharide (LPS) on lymphoid and non-lymphoid cells in the mouse spleen. In order to find out whether LPS localizes in and/or on cells that are affected by this compound, the aim of the present study was to investigate the localization of intravenously injected LPS in the mouse spleen using an immunoperoxidase technique. At different time points after injection, the localization of LPS is demonstrated and LPS-containing cells are characterized. Most of the injected LPS has been taken up by marginal zone macrophages at 2 h after its administration whereas macrophages in the red pulp and at the periphery of the white pulp (marginal metallophils) have ingested less LPS. In the periarteriolar lymphocyte sheath, LPS is concentrated in a large number of acid phosphatase-negative, Ia-positive, large branched cells which were suggested to represent interdigitating cells. Moreover an extracellular dendritic localization pattern of LPS is demonstrated in the corona and central parts of the follicles at different time intervals after its injection. The significance of the localization pattern of LPS in the mouse spleen is discussed.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Localization of intravenously injected lipopolysaccharide (LPS) in the spleen of the mouse. An immunoperoxidase and histochemical study. 285 97

The activities of acid phosphatase, alkaline phosphatase, glucose-6-phosphatase, uridine diphosphatase, inosine diphosphatase, thiamine pyrophosphatase and 5'-nucleotidase have been investigated cytochemically in hepatocytes of the offspring of alcohol-fed rats, using cerium ions as a capturing agent and qualitative and quantitative electron microscopy. All these enzyme activities were decreased in the experimental animals compared with controls not exposed to ethanol. The pattern of deposition of the product of glucose-6-phosphatase activity in the cisternae of the endoplasmic reticulum was also different in the two groups. The phosphatases analyzed are functional markers of different cell components, and the results suggest that prenatal exposure of rats to ethanol causes functional alterations in the endoplasmic reticulum, Golgi apparatus, lysosomes and plasma membrane of hepatocytes.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Alterations in the cytochemical activity of several phosphatases in hepatocytes from rats exposed prenatally to ethanol. 286 48

Acute pyelonephritis was induced in rats by temporary unilateral ureteric obstruction and the intravenous injection of Escherichia coli. Animals were sacrificed 48 h after infection and changes in renal cortical tubules due to the presence of bacteria were studied. Bacteria appeared and multiplied in the tubular lumina and proximal tubular epithelial cells endocytosed the microorganisms in large numbers. Coalescence of phagosomes with lysosomes resulted in the surrounding of engulfed bacteria with acid phosphatase. However, the lysosomal apparatus of the cells did not eliminate Escherichia coli since the bacteria multiplied within phagosomes and destroyed the normal cell architecture. The peritubular interstitial inflammatory infiltrate caused ischemia of tubules, enhancing bacterial damage to the proximal tubules. The cytoplasm of the injured tubular cells was sometimes detached from the basement membrane. Cells of the distal tubules and collecting ducts did not show significant endocytosis or bacterial tubular damage.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Phagocytosis of bacteria by proximal tubular epithelium in experimental pyelonephritis. 286 43

F344 rats were given vitamin A for four consecutive days and then their alveolar macrophages (AM phi) were obtained by bronchopulmonary lavage of the lung. Compared with unstimulated AM phi, AM phi from rats given vitamin A had more numerous and longer cytoplasmic projections, and these projections had many knobs on their sides and tip. The AM phi became attached to syngeneic mammary adenocarcinoma cells at many focal points and the tumor cells then lost surface microvilli around the contact zones. Detachment of the knobs from the projections on AM phi was often observed in areas of close association between AM phi and tumor cells. The detached knobs were 250 nm in diameter, gave a positive reaction for acid phosphatase, and frequently became attached to the surface of tumor cells. Then, many of the tumor cells in the vicinity of AM phi exhibited cytolytic changes. It is concluded that the cytotoxicity of stimulated AM phi is due to their attachment to the surface of tumor cells and their release of particles with acid phosphatase activity into the narrow space between the cells, and then to uptake of these particles by susceptible tumor cells.
Virchows Arch B Cell Pathol Incl Mol Pathol 1985
PMID:Ultrastructure of tumor cell interaction with alveolar macrophages stimulated by vitamin A. 286 45

Reovirus is a double-stranded RNA-virus which induces myocarditis in newborn mice. Due to the large diameter of the viral particles (70-75 nm) it can be detected by electron microscopy. Subcutaneous inoculation of 0.05 ml reovirus type 3 (TCID50-titer: 10(8.5)/ml) into newborn NMRI-mice (12-18 h after birth) caused a grey-yellow mottling on the ventricular surface first seen on the 5th day after birth. At the same time muscle fiber necrosis was observed which increased with time. Electron microscopic investigations of the diseased heart muscle disclosed a marked interstitial oedema, swelling of the tubular system and sarcoplasmic reticulum, and degenerative changes in the mitochondria of individual myocardiocytes as early as the 2nd post-inoculation day. Simultaneously, an enlarged Golgi-apparatus and an increasing number of lysosomes, partially exhibiting acid phosphatase activity, was detected in the perinuclear region of ventricular myocardiocytes. On the 5th day after infection, viruses were detected either within single membrane vesicles, dispersed in cytoplasm or as aggregated clusters in the perinuclear region. These in vivo electron microscopic findings correspond with observations of virus propagation in cell-culture systems.
Virchows Arch B Cell Pathol Incl Mol Pathol 1986
PMID:Experimental reovirus myocarditis in newborn mice. Electron microscopic observations. 287 May 87

Cultured cells derived from a mouse adrenocortical tumor transplant are unspecialized in appearance, but produce basal levels of steroids and demonstrate a near-immediate steroidogenic response to ACTH. There is biochemical evidence that ACTH induces increases in the uptake of serum lipoproteins by these cells and that this material is hydrolyzed in lysosomes to free cholesterol, a precursor for steroid end products. To investigate morphologically the role of lysosomes in the steroidogenic activity of these cells, cultures were incubated for 4 h with and without ACTH, then processed for the ultrastructural localization of acid phosphatase (ACPase), a marker enzyme for lysosomes, and for GERL, the lysosome-forming subcompartment of the Golgi, and examined by TEM and HVEM. Steroid output was determined by a fluorometric technique. Unstimulated cells secreted basal levels of steroids. By TEM, large endosomes, some containing semi-compact material and ACPase reaction product, were occasionally seen at the cell periphery and in the Golgi region. The Golgi and GERL were poorly developed. Residual bodies, a few of them ACPase+, appeared in the Golgi region and in microtubule-associated clusters near the cell membrane. ACTH-stimulated cells secreted steroids at 8-10 fold basal values. In TEM records, they displayed numerous ACPase+ endosomes between the cell periphery and the Golgi. The Golgi and GERL regions appeared to be hypertrophied and many large, inclusion-containing, strongly ACPase+ residual bodies appeared here and in elongated microtubule-containing cell processes. HVEM micrographs showed more definitively that ACTH produced distinct increases in the size of GERL and in the number of ACPase+ organelles. Our results suggest that in unstimulated cells, endosomes, presumably containing media-derived material, gain lysosomal enzymes in or near GERL, are transformed to residual bodies as their contents are hydrolyzed, and are subsequently translocated by microtubules to the cell periphery for exocytosis. ACTH appears to intensify all of these effects. The "giant" lysosomes seen in stimulated cells may result from a fusion of smaller lysosomes. Their amorphous contents may reflect an inefficient hydrolysis of LDL to free cholesterol.
Virchows Arch B Cell Pathol Incl Mol Pathol 1986
PMID:The effects of ACTH on acid phosphatase activity in endosomes, GERL and lysosomes of cultured adrenal tumor cells. 287 77


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