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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Seven mutants of Saccharomyces cerevisiae deficient in production of extracellular glucoamylase have been analyzed. For each of the seven a monogenic pattern of inheriting the mutant phenotype has been observed. The mutations have been shown to map within five different genetic loci, three independent mutations affecting the STA2 locus and the other four residing in four formerly unidentified genes. As expected, the sta2 mutants recover the wild phenotype when transformed with a STA2-bearing multicopy plasmid. Such reversion has also been observed for the transformed stall mutant. Unlike the others, the sta16 mutant is unable to secrete heterologous alpha-amylase encoded by a plasmid-borne DNA fragment. All the mutants have a moderately reduced ability to secrete the invertase and acid phosphatase.
Mol Gen Mikrobiol Virusol 1990 May
PMID:[Mutational analysis of the starch utilization system in the yeast Saccharomyces cerevisiae]. 219 27

Airway intra-luminal macrophages (AI-LM) are a little-studied subpopulation of pulmonary macrophages that are located on the surfaces of the conducting airways of the lower respiratory tract. In this study, we: (1) developed a flow cytometric approach by which AI-LM can be viably isolated in high purity from cell suspensions obtained by airway washings; (2) comparatively examined various functional, biochemical, biophysical, and morphologic features of the rat's AI-LM and alveolar macrophage (AM) phenotypes, and (3) investigated the origin of the AI-LM in the rat. Airway cells were harvested from the tracheas of adult Fischer-344 rats, and AM were obtained from the lungs by conventional bronchopulmonary lavage or via prosthetic airway circuits that supplanted the removed tracheas. Flow cytometric analyses of lavaged airway cells revealed that the AI-LM fell within the range of the electro-optical phenotype of AM, and subsequent cell-sorting experiments demonstrated that virtually all viable AI-LM could be sorted from contaminating airway epithelial cells in greater than 95% purity based on their electro-optical characteristics, e.g., electronic volume, axial light loss, 90 degrees light scatter, and blue and green autofluorescence signals. In Fc gamma receptor-mediated phagocytic studies, approximately 90% of AM engulfed opsonized erythrocytes (EIgG) whereas only 60% of the AI-LM were able to do so. Comparisons of the numbers of EIgG in phagocytic AM and in phagocytic AI-LM indicated the AI-LM were less phagocytic. Densitometric analyses of sorted AI-LM and of sorted AM stained for acid phosphatase, nonspecific esterase, and beta-glucuronidase indicated that the activities of these enzymes were generally less in the AI-LM than in the AM. Morphometric comparisons of sorted AM and of sorted AI-LM showed that the AI-LM were generally larger than the AM and that the surfaces and nuclei of the AI-LM were more regular than those of the AM. The AI-LM were found to strongly label with the monoclonal antibody ED1, which recognizes an antigen on the surfaces of rat AM, but the AI-LM did not label with the monoclonal antibody ED2, which recognizes an antigen on the surfaces of rat peribronchial and pulmonary perivascular macrophages. Over the course of alveolar phase clearance of a lung burden of polystyrene microspheres, the frequency distributions of the particles in AI-LM and in AM were found to be virtually identical.(ABSTRACT TRUNCATED AT 400 WORDS)
Am J Respir Cell Mol Biol 1990 Oct
PMID:Airway intra-luminal macrophages: evidence of origin and comparisons to alveolar macrophages. 220 41

Monensin, an inhibitor of Golgi function, was used to investigate the role of this cell compartment in the glycosylation of Leishmania donovani promastigote secretory acid phosphatase (EC 3.1.3.2). Monensin-treated cells demonstrated morphological changes in the Golgi complex and secreted enzyme with an altered electrophoretic mobility: two discrete bands of approximately 95 and 110 kDa were found, as compared to the heterodisperse nature of the enzyme from untreated controls. Chemical deglycosylation by mild acid hydrolysis resulted in a similar effect on the electrophoretic mobility of purified extracellular enzyme. Acid phosphatase was also treated with N-glycosidase F (EC 3.5.1.52) to remove N-linked oligosaccharides. The altered lectin-binding properties of the enzyme after these two treatments demonstrated that an unusual type of galactose-containing acid-labile carbohydrate was present in secretory acid phosphatase in addition to the N-linked oligosaccharides. Further, experiments with 32P-labelled enzyme indicated that phosphodiester bonds were the structural component responsible for the sensitivity of this carbohydrate to mild acid hydrolysis. Cumulatively, these results demonstrated that a novel form of Golgi-mediated posttranslational modification had occurred to the secretory acid phosphatase presumably by the addition of an acid-labile phosphoglycan.
Mol Biochem Parasitol 1990 Mar
PMID:Golgi-mediated post-translational processing of secretory acid phosphatase by Leishmania donovani promastigotes. 232 58

We have identified human, mouse, and chicken homologs to Xenopus S6 protein kinase II (S6KII). In quiescent cells, the apparent molecular mass of the Xenopus homologs (referred to as pp90rsk) increased from a range of 81 to 91 to a range of 85 to 92 kilodaltons following serum addition, which is consistent with an increase in protein phosphorylation. Indeed, serum growth factors stimulated pp90rsk phosphorylation at multiple serine and threonine residues. Furthermore, pp90rsk activity was stimulated within seconds of serum addition. Distinct molecular sizes, chromatographic properties, phosphopeptide maps, and kinetics of activation, the lack of immunological cross-reactivity, and analysis of S6 kinase activities in cells that overexpressed pp90rsk suggest that pp90rsk and pp70-S6 protein kinase, a previously identified mitogen- and oncogene-regulated S6 kinase in cultured cells, are distinct and differentially regulated. The notion that both enzymes are regulated by protein phosphorylation was supported by the ability to inactivate their S6 phosphotransferase activities with potato acid phosphatase. These data demonstrate that homologs to the Xenopus S6 protein kinases are produced and regulated by protein phosphorylation in somatic cells and that, in addition to a proposed role in Xenopus oocyte maturation, these homologs may participate in the initiation of animal cell proliferation.
Mol Cell Biol 1990 Jun
PMID:Identification of Xenopus S6 protein kinase homologs (pp90rsk) in somatic cells: phosphorylation and activation during initiation of cell proliferation. 234 72

The uteroferrin(Uf)-associated basic proteins (UfAP) are a group of three (Mr = 42K, 48K, and 50K) antigenically related, basic glycoproteins secreted by the porcine uterus under the influence of progesterone (P4) which exist as heterodimers (Mr = 80,000) with the iron-binding acid phosphatase, Uf. Several UfAP cDNA clones from a day-60 pregnant pig uterine endometrial cDNA library have been cloned and sequenced. The UfAP mRNA is approximately 1400 bases long and has a single open reading frame of 1251 bases with two start codons at positions 64 and 79 from the 5'-end. UfAP mRNA content of the endometrium increases as pregnancy proceeds, reaching maximum levels around day 70 and then remaining relatively constant in late gestation (days 70 to 110). The pro-form of the UfAP minus signal sequence appears to be 392 amino acids in length and has four potential N-linked glycosylation sites Asn107, Asn197, Asn243, and Asn315. Comparison of the NH2-terminal sequences of the individual UfAP poly-peptides with the amino acid sequence deduced from the cDNA has indicated a series of at least four posttranslational proteolytic processing steps which generate the various molecular forms of the UfAP. The deduced amino acid sequence of UfAP shares considerable identity with several protease inhibitors and hormone-binding proteins that are members of the serpin superfamily of proteins. The UfAP amino acid sequence also exhibits about 55% sequence identity with the P4-induced uterine milk proteins (UTMP) of the sheep. Since the UfAP and UTMP share many biosynthetic and structural features that include site of biosynthesis in the endometrium, P4-responsiveness, the presence of the mannose 6-phosphate lysosomal recognition marker, and considerable sequence similarity, the UfAP and the UTMP may have homologous function which for both still remains obscure.
Mol Endocrinol 1990 Mar
PMID:Molecular cloning of the uteroferrin-associated protein, a major progesterone-induced serpin secreted by the porcine uterus, and the expression of its mRNA during pregnancy. 234 77

Structural gene mutants of the cell-surface glycoprotein acid phosphatase of Schizosaccharomyces pombe were analysed to define structural determinants that are responsible for enzymatic activity, N-glycosylation and secretion. All seven defined mutations cause a single amino acid substitution in the mature acid phosphatase protein and destroy the enzymatic activity. The mutational lesions are distributed throughout the pho1 gene. A ser to phe substitution at position 349 abolishes enzymatic activity only and does not affect glycosylation and secretion. Two mutations create a new N-glycosylation site by substitution of pro at position 56 by phe and ser, respectively. This new site is apparently used in the mutants. Their core-glycosylated acid phosphatase is slightly larger than that of the wild type. Overglycosylation seems not to affect secretion. Four different mutations (a gly to asp substitution at position 281 and ser to phe substitutions at positions 150, 271 and 277) cause intracellular accumulation of enzymatically inactive core-glycosylated acid phosphatase precursor. These mutational lesions apparently block transport of acid phosphatase from the endoplasmic reticulum to the Golgi apparatus.
Mol Gen Genet 1990 May
PMID:Effects of seven different mutations in the pho1 gene on enzymatic activity, glycosylation and secretion of acid phosphatase in Schizosaccharomyces pombe. 238 21

A differentiating keratinocyte cell line derived from explant cultures of rat sublingual epithelium has been used as a potential in vitro model for topical (skin) irritation of a range of detergents. The end points used to assess toxicity were acid phosphatase (AP) activity after 4 h of dosing and neutral red (NR) uptake and kenacid blue (KB) staining after 3 d to assess cell viability and number. The acid phosphatase activity increased to a sharp peak with increasing doses, then fell equally sharply for the anionic detergent sodium dodecyl sulfate (SDS) and cationic detergents TMABs (trimethylammonium bromides). With the Tweens (the least toxic group) there was no acid phosphatase peak or it appeared at the highest dose level used (1.0 mg/ml). The dose-response curves for NR uptake paralleled those for KB staining. With all of the three end points, it was apparent that the order of toxicity for the different groups was TMABs greater than SDS greater than Tweens, with a difference of one order of magnitude between consecutive groups when using NR and KB.
Mol Toxicol
PMID:Irritancy testing in cultured keratinocytes. 247 73

A technique is presented for isolating a subclass of lysosomes, designated crinosomes, by one-step floating-up centrifugation in a cesium-containing sucrose gradient. Rats were treated with vinblastine in order to induce the formation of crinosomes. Vinblastine blocked exocytosis of secretory granules at the cell border. Later on, lipoprotein-containing granules were seen throughout the cytoplasm. Immunolabeling with polyclonal antibodies against albumin demonstrated a severalfold greater presence of gold particles over crinosomes and Golgi cisternae than over the surrounding organelles. The induction of crinosomes by vinblastine made it possible to isolate thenm on a sucrose gradient. These organelles contained marker enzymes for the Golgi complex (galactosyl transferase) and lysosomes (cathepsins). The purity of the fraction was high. The crinosomes were proteolytically and lipolytically very active. The crinosomes were positive to cytochemical acid phosphatase staining. It is concluded that crinosomes develop from fusion between lysosomes and secretory granules and that they are active in degrading retained secretory material.
Exp Mol Pathol 1989 Apr
PMID:Isolation and characterization of crinosomes--a subclass of secondary lysosomes. 249 80

The mode of expression was investigated for two positive regulatory genes, PHO2 and PHO4, whose products are indispensable for the transcriptional control of the structural genes of repressible acid phosphatase and the inorganic phosphate (Pi) transport system in Saccharomyces cerevisiae. Northern analysis of poly(A)+ RNA of the wildtype and the pho regulatory mutants with PHO4 DNA as hybridization probe and expressional analysis of a pho4'-'lacZ fused gene on a YEp plasmid revealed that PHO4 is expressed at a low level, constitutively, and independently of the PHO regulatory system and Pi in the medium. Similar analyses with PHO2 DNA indicated that PHO2 is expressed at an even lower level than PHO4, and is repressed by Pi and by the active PHO2 product, possibly at the translational level, while retaining a substantial level of basal activity.
Mol Gen Genet 1989 May
PMID:Mode of expression of the positive regulatory genes PHO2 and PHO4 of the phosphatase regulon in Saccharomyces cerevisiae. 250 53

The ultrastructure of binding, internalization, and translocation of beta-migrating very low density lipoprotein (beta-VLDL) and acetylated low density lipoprotein (Ac-LDL) by cultured pigeon monocytes was examined using lipoprotein-gold conjugates. Through morphometry, differences in the binding and uptake of beta-VLDL-gold and Ac-LDL-gold were documented. Cells exposed to either beta-VLDL-gold or Ac-LDL-gold for 2 hr at 4 degrees C had the label over noncoated regions of the plasma membrane. Upon warming the cells to 37 degrees C for 2 min, 35% of the surface-bound beta-VLDL-gold was within coated pits on the cell surface. Although coated pits occupied less than 2% of the surface, binding of beta-VLDL-gold was 53 times more concentrated in coated pits as compared to noncoated membrane regions. In contrast, Ac-LDL-gold neither bound to coated pits nor relocated into coated regions of the membrane upon warming to 37 degrees C. Both the beta-VLDL-gold and the Ac-LDL-gold were internalized when the cells were rewarmed at 37 degrees C. Most of the internalized gold particles for both lipoproteins were located in electron-lucent vesicles; however, 9% of the intracellular beta-VLDL-gold was observed within coated vesicles at early times. Upon prolonged rewarming (30-90 min), both lipoprotein-gold conjugates were within acid phosphatase-positive lysosomes. Ultimately 83% of the Ac-LDL-gold and 90% of the beta-VLDL-gold were within electron-dense and electron-lucent lysosomes. These results suggested that the receptor-mediated binding and internalization of beta-VLDL and Ac-LDL by pigeon monocyte macrophages proceeded by separate, distinct routes; beta-VLDL by both coated and noncoated pathways while Ac-LDL was internalized exclusively by noncoated mechanisms. Regardless of these internalization differences, both lipoproteins were delivered to lysosomes for degradation.
Exp Mol Pathol 1989 Dec
PMID:Morphological characterization of beta-VLDL and acetylated-LDL binding and internalization by cultured pigeon monocytes. 251 25


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