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)

AA-amyloidosis was induced in hamsters receiving amyloid-enhancing factor (AEF) by daily subcutaneous injection with either an aged casein solution or casein supplemented with lipopolysaccharide (LPS). Both amyloid inducers gave similar results with respect to amyloid development in spleen, liver and kidneys and to serum amyloid A (SAA) concentrations and plasma cathepsin D activities. AEF was isolated from amyloid-containing tissue by the method described by Hol et al. (1985), and amyloid-enhancing material was also extracted from isolated hamster amyloid fibrils by intensive sonification. This fibril-derived amyloid-enhancing material lacked typical green birefringence after staining with Congo red and appeared as amorphous material on electron microscopy. AEF shortened the pre-amyloid phase for splenic and hepatic amyloid development and also the subsequent interval before renal amyloid deposition. This indicates that endogenous AEF, unlike passively transferred preformed AEF, is not distributed throughout the body and is probably generated at the site of amyloid deposition. Moreover, these results suggest that amyloid deposition in the kidneys, like that in the spleen and liver, involves an AEF-dependent pathway. Thus redistribution of amyloid is probably not an important cause of renal amyloid involvement. In addition to the reduction in the lag phase for splenic and hepatic amyloid deposition, AEF also speeds the changes in SAA concentration and plasma cathepsin D activity. This indicates that AEF accelerates rather than eliminates the pre-amyloid phase.
Virchows Arch B Cell Pathol Incl Mol Pathol 1986
PMID:Amyloid-enhancing factor (AEF) in the pathogenesis of AA-amyloidosis in the hamster. 287 82

An endogenous thermostable activator of Protein kinase III (PKIII) was purified from 100,000 X g supernatants of Neurospora crassa mycelial extracts. This 38,000 dalton polypeptide, clearly separable from calmodulin on P-60 gel filtration, specifically stimulated N. crassa PKIII activity on casein or phosvitin "in vitro" phosphorylation. The factor was only present in the initial growth phase of the fungus. The mechanism of PKIII activation and its possible regulatory role are discussed.
Mol Cell Biochem 1987 Sep
PMID:A novel stimulator of protein phosphorylation in Neurospora crassa. 296 77

The goal of this work was to establish an assay for transformation of epithelial cells. Two epithelial cell lines were obtained after microinjecting transforming genes into primary rabbit mammary secretory cells. The cell lines were analyzed for their oncogenic potential and for the maintenance of a differentiated phenotype. A fully transformed cell line, which retained epithelial cell organization, was obtained by coinjecting simian virus 40 DNA and the activated human c-Ha-ras gene. The proliferation rate of these cells was high, with a doubling time of 16 h. Their growth was anchorage independent, and they had lost contact inhibition. The cells were tumorigenic in nude mice, but had no metastatic potential. Both microinjected DNAs were efficiently transcribed and translated, in contrast to the casein genes, which were expressed in primary cells but not in the transformed cell line. An immortalized cell line established after injection with simian virus 40 DNA alone was characterized by a moderate rate of proliferation with a doubling time of approximately 30 h. The growth of these cells was contact inhibited and anchorage dependent. The cells were not tumorigenic in nude mice. The viral DNA was expressed during early passages, as shown by the presence of the large T antigen in cell nuclei, but not at later passages. A high number of lactogenic hormone receptors were found associated with the cell surface. Despite the presence of these receptors, no induction of genes coding for milk proteins was observed after addition of prolactin. These data demonstrate that this assay system can be used to assess the immortalizing and transforming potential of candidate oncogenes in epithelial cells.
Mol Cell Biol 1986 Jun
PMID:Establishment of two rabbit mammary epithelial cell lines with distinct oncogenic potential and differentiated phenotype after microinjection of transforming genes. 302 14

The Rous sarcoma virus (RSV) pp60v-src protein was expressed in Saccharomyces cerevisiae cells either from a plasmid vector carrying the v-src gene or in yeast cells containing a single-copy v-src gene chromosomally integrated. In both yeast strains, v-src gene transcription is regulated by the galactose-inducible GAL10 promoter. Growth in galactose-containing medium resulted in constitutive expression of pp60v-src in the integrated strain and transient expression of higher levels of pp60v-src in the plasmid-bearing strain. The concentration of pp60v-src in the plasmid-bearing strain at its peak of expression was approximately threefold lower than that found in RSV-transformed mammalian cells. pp60v-src synthesized in yeast cells was phosphorylated in vivo on sites within the amino and carboxyl halves of the molecule. In immune complex kinase assays, the yeast pp60v-src was autophosphorylated on tyrosine and was able to phosphorylate exogenous substrates such as casein and enolase. The specific activity of pp60v-src synthesized in yeast cells was approximately 5- to 10-fold higher than that made in mammalian cells. Induction of pp60v-src caused the death of the plasmid-bearing yeast strain and transient inhibition of growth of the single-copy strain. Concomitantly, this induction resulted in high levels of tyrosine phosphorylation of yeast cell proteins. This indicates that pp60v-src functions as a tyrosine-specific phosphotransferase in yeast cells and suggests that hyperphosphorylation of yeast proteins is inimical to cell growth.
Mol Cell Biol 1987 Jun
PMID:Expression of Rous sarcoma virus transforming protein pp60v-src in Saccharomyces cerevisiae cells. 303 49

Three cyclic AMP (cAMP)-dependent protein kinases, designated A1, A2, and B, were isolated from the liver fluke Fasciola hepatica using Phenyl-Sepharose and DEAE-cellulose chromatography. These enzymes differed with respect to activation by cAMP and their molecular weights. The half-maximal activation constant for cAMP-dependent protein kinases A1 and B was 20 nM, while that of A2 was about five-fold higher (110 nM). The estimated molecular weights for cAMP-dependent protein kinases A1 and A2 (both 98,000) suggest a dimeric form for these enzymes; whereas, the higher molecular weight for cAMP-dependent protein kinase B (187,000) indicates that this enzyme is a tetramer. The physical and kinetic properties of the catalytic subunit of fluke cAMP-dependent protein kinase were similar to those reported for the mammalian enzyme. The molecular weight of the catalytic subunit was estimated to be 41,000. The pH optimum for the enzyme was 6.0, 6.5, or 7.0 when casein, histone, or protamine were used as substrates. The protein substrate specificity was in the order histone greater than arginine-rich histone greater than casein greater than protamine greater than lysine-rich histone. Free Mg2+ 'stimulated' enzyme activity at low concentrations (0.5 to 5 mM), whereas at higher concentrations (greater than 5 mM) it became inhibitory. Of the divalent cations tested, only Co2+ and Mn2+ could substitute for Mg2+. Kinetic studies indicated that the reaction mechanism of this enzyme is sequential and that MgATP and MgADP are competitive ligands. Reconstitution experiments using the subunits of fluke and bovine heart cAMP-dependent protein kinase showed that there is sufficient structural homology between these enzymes such that the catalytic subunit from one species can combine with the regulatory subunit of the other species to form inactive holoenzyme. Thus, the present results indicate that cAMP-dependent protein kinase from F. hepatica is similar but not identical to the mammalian enzyme.
Mol Biochem Parasitol 1987 Apr
PMID:Partial purification and characterization of cAMP-dependent protein kinase from Fasciola hepatica. 303 68

Schistosomula of Schistosoma mansoni which are mechanically transformed at 4 degrees C and are then incubated at 37 degrees C in defined medium spontaneously secrete two proteases, a major one of 28 kDa and a minor one of 60 kDa. These were purified by ion exchange chromatography on DEAE-cellulose and gel filtration on Ultrogel AcA 54 with yields of 33% and 29%, respectively. Both appeared as single bands by silver staining following sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis. The 28 kDa protease is a glycoprotein that has a pI of 11 or higher and an optimal activity around pH 9.0. It cleaves casein, gelatin and human C3 and C3b. It is metal-ion independent and is inhibited by diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, soy-bean trypsin inhibitor, alpha 1 antitrypsin, Zn2+ ions, sodium dodecyl sulphate and normal human serum. The 60 kDa protease is a glycoprotein with a pI of 9.2. It can also cleave casein and gelatin and its activity is inhibited by phenylmethanesulfonyl fluoride but not by diisopropyl fluorophosphate or sodium dodecyl sulphate. We suggest that these proteases may play a role during cercarial penetration of the skin and in shedding of the cercarial glycocalyx.
Mol Biochem Parasitol 1988 Jul
PMID:Purification and characterization of proteases secreted by transforming schistosomula of Schistosoma mansoni. 304 Dec 76

Casein kinase II of Saccharomyces cerevisiae contains two distinct catalytic subunits, alpha and alpha', which must be encoded by separate genes (R. Padmanabha and C. V. C. Glover, J. Biol. Chem. 262:1829-1835, 1987). The gene encoding the 42-kilodalton alpha subunit has been isolated by screening a yeast genomic library with oligonucleotide probes synthesized on the basis of the N-terminal amino acid sequence of the polypeptide. This gene (designated CKA1) contains an intron-free open reading frame of 372 amino acid residues. The deduced amino acid sequence is 67% identical to the alpha subunit of Drosophila melanogaster casein kinase II. The CKA1 gene product appears to be distantly related to other known protein kinases but exhibits highest similarity to the CDC28 gene product and its homolog in other species. Gene replacement techniques have been used to generate a null cka1 mutant allele. Haploid and diploid strains lacking a functional CKA1 gene appear to be phenotypically wild type, presumably because of the presence of the alpha' gene. Interestingly, the CKA1 gene appears to be single copy in the yeast genome; i.e., the alpha' gene, whose existence is known from biochemical studies and protein sequencing, cannot be detected by low-stringency hybridization.
Mol Cell Biol 1988 Nov
PMID:Isolation, sequencing, and disruption of the CKA1 gene encoding the alpha subunit of yeast casein kinase II. 306 76

The mechanism by which individual peptide and steroid hormones and cell-substratum interactions regulate milk protein gene expression has been studied in the COMMA-D mammary epithelial cell line. In the presence of insulin, hydrocortisone, and prolactin, growth of COMMA-D cells on floating collagen gels in comparison with that on a plastic substratum resulted in a 2.5- to 3-fold increase in the relative rate of beta-casein gene transcription but a 37-fold increase in beta-casein mRNA accumulation. In contrast, whey acidic protein gene transcription was constitutive in COMMA-D cells grown on either substratum, but its mRNA was unstable and little intact mature mRNA was detected. Culturing COMMA-D cells on collagen also promoted increased expression of other genes expressed in differentiated mammary epithelial cells, including those encoding alpha- and gamma-casein, transferrin, malic enzyme, and phosphoenolpyruvate carboxykinase but decreased the expression of actin and histone genes. Using COMMA-D cells, we defined further the role of individual hormones in influencing beta-casein gene transcription. With insulin alone, a basal level of beta-casein gene transcription was detected in COMMA-D cells grown on floating collagen gels. Addition of prolactin but not hydrocortisone resulted in a 2.5- to 3.0-fold increase in beta-casein gene transcription, but both hormones were required to elicit the maximal 73-fold induction in mRNA accumulation. This posttranscriptional effect of hormones on casein mRNA accumulation preceded any detectable changes in the relative rate of transcription. Thus, regulation by both hormones and cell substratum of casein gene expression is exerted primarily at the post transcriptional level.
Mol Cell Biol 1988 Aug
PMID:Both cell substratum regulation and hormonal regulation of milk protein gene expression are exerted primarily at the posttranscriptional level. 306 79

Kinetic parameters for the splitting of model peptide substrates and chi-casein with chymosin have been interpreted on the basis of the three-dimensional structure of chymosin. Model peptide substrates contain a fragment of the chi-casein sequence in the region of the bond Phe-105--Met-106 splitted with the enzyme. It was shown that the possible reason of the enormous milk-clotting efficiency of chymosin may be partly associated with the electrostatic interaction of the positive charged segment 98-102 (His-Pro-His-Pro-His) of the substrate and outer loop of the enzyme which contains Glu-245, Asp-247, Asp-249, Asp-251.
Mol Biol (Mosk)
PMID:[The role of peripheral interactions in chymosin specificity]. 312 29

A 107 kDa (pp107) casein kinase G (ck-G) substrate has been purified from mouse and beef thyroid cytosol; ck-G was purified from beef thyroid cytosol. Ck-G and pp107 were found to co-elute on DEAE cellulose chromatography at approximately 300 mM NaCl. Ck-G and pp107 were separated by spermine-agarose affinity chromatography; pp107 is eluted with a stepped gradient at 250 mM NaCl and ck-G is eluted at 500 mM NaCl. Ck-G was subsequently purified by casein-agarose and GTP-agarose affinity chromatography. The 107 kDa protein was purified using heparin-agarose affinity chromatography. Phosphorylation of purified pp107 by ck-G was stimulated by spermine (ED50 = 0.2 mM) and inhibited by low concentrations of heparin (0.1-5 micrograms/ml). The Km and Vmax for the reaction were 1.46 microM and 32.2 nmoles P transferred/20 min/mg protein, respectively; 1 mole pp107 incorporated 0.81 mole phosphorus. pp107 was found to be an acidic substrate with a pI of 3.87 and was absorbed to wheat-germ agglutinin-agarose. The specificity of pp107 phosphorylation was studied using diacylglycerol-activated calcium/phospholipid-dependent protein kinase C, calcium-activated calmodulin-dependent protein kinase, and the catalytic subunit of cAMP-dependent protein kinase A. Phosphorylation of pp107 by the other protein kinases tested never exceeded 4% of that of ck-G. Our data show that pp107 is an acidic glycoprotein which may serve as a high-affinity and specific substrate for ck-G.
Mol Cell Biochem 1988 Oct
PMID:Purification of a 107 kilodalton (kDa) casein kinase G substrate from thyroid cytosol. 320 Feb 52


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