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Query: UNIPROT:P06889 (Mol)
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The Saccharomyces cerevisiae GPA1, STE4, and STE18 genes encode products homologous to mammalian G-protein alpha, beta, and gamma subunits, respectively. All three genes function in the transduction of the signal generated by mating pheromone in haploid cells. To characterize more completely the role of these genes in mating, we have conditionally overexpressed GPA1, STE4, and STE18, using the galactose-inducible GAL1 promoter. Overexpression of STE4 alone, or STE4 together with STE18, generated a response in haploid cells suggestive of pheromone signal transduction: arrest in G1 of the cell cycle, formation of cellular projections, and induction of the pheromone-inducible transcript FUS1 25- to 70-fold. High-level STE18 expression alone had none of these effects, nor did overexpression of STE4 in a MATa/alpha diploid. However, STE18 was essential for the response, since overexpression of STE4 was unable to activate a response in a ste18 null strain. GPA1 hyperexpression suppressed the phenotype of STE4 overexpression. In addition, cells that overexpressed GPA1 were more resistant to pheromone and recovered more quickly from pheromone than did wild-type cells, which suggests that GPA1 may function in an adaptation response to pheromone.
Mol Cell Biol 1990 Feb
PMID:Stoichiometry of G protein subunits affects the Saccharomyces cerevisiae mating pheromone signal transduction pathway. 210 53

Subunits alpha, beta and gamma of adenosine triphosphatase (H(+)-ATPase) from the thermophilic bacterium PS3 (TF1) have been over-expressed in Escherichia coli. alpha and beta subunits deuterated to the level of 90% were obtained by culturing E. coli in 2H2O medium. Both the subunits and the reconstituted alpha beta gamma complex, TF1, which contain the deuterated components in various combinations, were studied in solution by small-angle neutron scattering. The individual shapes of the subunits and their organization in the alpha beta gamma-TF1 complex were examined using the techniques of selective deuteration and contrast variation. The alpha and beta subunits are well approximated as ellipsoids of revolution having minor semi-axes of 20.4(+/- 0.4) and 20.0(+/- 0.2) A, and major semi-axes of 53.0(+/- 1.4) and 55.8(+/- 0.9) A, respectively. In the TF1 complex, three beta subunits are aligned to form an equilateral triangle, with their major axes tilted by 35 degrees with respect to the 3-fold axis of the complex. The beta-beta distance is about 53 A. Three alpha subunits are similarly arranged, positioned between the beta subunits, and with their direction of tilt opposite to that of the beta subunits. The centers of the alpha and beta subunits lie in the same plane, forming a hexagon. Adjacent subunits overlap in this model, suggesting that they are not simple ellipsoids of revolution.
J Mol Biol 1990 May 20
PMID:Small-angle neutron scattering from the reconstituted TF1 of H(+)-ATPase from thermophilic bacterium PS3 with deuterated subunits. 214 Apr 19

Two-dimensional nuclear magnetic resonance (n.m.r.) spectroscopy and a variety of computational techniques have been used to generate three-dimensional structures of the two DNA duplexes d(CGCCTAATCG) and d(CGTCACGCGC). The central six base-pairs in these two decamers contain all ten dinucleotide pairs in DNA and thus, represent a model system for investigating how the local structure of DNA varies with base sequence. Resonance assignments were made for the non-exchangeable base protons and most of the C-1'-C-4' sugar protons in both decamers. Three-dimensional structures were generated using a distance geometry algorithm and these initial structures were refined by optimizing the fit of back-calculated spectra against the experimental two-dimensional nuclear Overhauser effect (NOE) spectra. This back-calculation procedure consists of calculating NOE cross relaxation rates for a given structure by solution of the Bloch equations, and directly accounts for spin diffusion effects. Use of this refinement procedure eliminates some assumptions that have been invoked when generating structures of DNA oligomers from n.m.r. data. Constrained energy minimization and constrained quenched molecular dynamics calculation were also performed on both decamers to help generate energetically favorable structures consistent with the experimental data. Analysis of the local conformational parameters of helical twist, helical rise, propeller twist, displacement and the alpha, beta, gamma, epison and zeta backbone torsion angles in these structures shows that these parameters span a large range of values relative to the X-ray data of nucleic acids. However, the glycosidic and pseudorotation angles are quite well defined in these structures. The implications that these results have for determination of local structural variations of DNA in solution, such as those predicted by Callidine's rules, are discussed. Our results differ significantly from some previous studies on determining local conformations of nucleic acids and comparisons with these studies are made.
J Mol Biol 1990 Aug 05
PMID:Determining local conformational variations in DNA. Nuclear magnetic resonance structures of the DNA duplexes d(CGCCTAATCG) and d(CGTCACGCGC) generated using back-calculation of the nuclear Overhauser effect spectra, a distance geometry algorithm and constrained molecular dynamics. 216 79

Antitumor activity, mitogenicity, and lethal toxicity of chemically synthesized lipid A analogs, acylglucosamine-4- or -6-phosphate with the alpha, beta-hydroxyacyl, acyloxyacyl, or hydroxyacyloxacyl groups at the C-2 and C-3 positions, were examined. Meth A fibrosarcoma cells (5 X 10(5)) were inoculated subcutaneously into BALB/c mice on day 0, and six compounds (50 micrograms/mouse) were administered intravenously on days 7 and 9. Although the antitumor activity of these compounds was weaker than that of natural lipopolysaccharide (LPS) or the synthetic lipid A analog (506) of Escherichia sp type, all groups exhibited tumor inhibition rates of 40% to 50% and delayed tumor growth. Six compounds, with the exception of compound A-173 (with the hydroxytetranoyl group at the C-2 and C-3 positions), were capable of increasing the incorporation of [3H]thymidine into cultured splenocytes of C57BL/6 mice, and caused lethal toxicity in C57BL/6 mice sensitized with galactosamine. However, these compounds had lower toxicity than bacterial LPS (about 500- to 1,000-fold). Compounds A-172 and A-174, which have the same structure except for the C-4 or C-6 position of the phosphate group, exerted similar antitumor activity, mitogenicity, and lethality. The results discussed above indicate that the biologic activity of these compounds correlates with the carbon number of fatty acid but is not affected by the different location of the phosphate group. Furthermore, it seems that the difference between the alpha, beta-hydroxy position of fatty acid and the R or S configuration does not alter the biologic effects.
Mol Biother 1990 Jun
PMID:Antitumor activity against Meth A fibrosarcoma and biologic activities of synthetic monosaccharide analogs of lipid A in mice. 236 54

Native preparations of alpha, beta and gamma-interferons as well as recombinant beta-interferon and purified leukocyte alpha-interferon and purified leukocyte alpha-interferon exert antiviral and antiproliferative activity in CaOv cells. Native interferon preparations were shown to be more antiproliferative than purified interferons per unit of antiviral activity (with EMC as well as with less susceptible VSV used as test viruses). It was shown that level of 2'5' oligoadenylatesynthetase activity induction in general correlates with antiproliferative and pronounced antiviral activity of interferons, besides that, the earlier (by 11 hours) induction of the enzyme activity by beta-interferon correlates with more rapid expression of antiproliferative effects by this interferon in comparison with that of alpha-interferon, the latter inducing the peak of enzyme activity by 24 hours.
Mol Gen Mikrobiol Virusol 1986 Apr
PMID:[Antiviral and antiproliferative activity of human interferons and their induction of 2',5'-oligoadenylate synthetase]. 243 19

The large granular lymphocyte (LGL) population, which effects a natural killer (NK) function, consists of cells whose lineage derivation has not been clearly established on the basis of phenotypic and functional properties. To clarify the relationship of LGL/NK cells to T cells we studied patterns of rearrangement and expression of the T cell receptor (Ti) genes alpha, beta, and gamma in normal human LGLs; in CD8+, CD8-, Mol+, and Mol- LGL subsets; and in 17 cases of leukemic LGL proliferations (T gamma LPD). T alpha, T beta, and T gamma genes were not expressed, nor were T beta and T gamma genes rearranged in normal LGLs or LGL subsets. The T gamma LPD were divided into two groups. One group (15/17 cases) was characterized as CD3+ and displayed Ti gene rearrangements. Seven of these cases were reactive with monoclonal antibody WT31, which suggested expression of an alpha/beta heterodimer on the cell surface. The other group (2/17 cases) was CD3- with unrearranged Ti genes. These results indicate that the normal LGL/NK population is homogeneous and distinct from the normal T cell population because it does not express, and as a result, cannot effect its immune function through the T cell receptor molecules. Conversely, T gamma LPDs represent a heterogeneous group of lymphoproliferative diseases within which the CD3-, Ti- cases most likely represent the neoplastic counterpart of normal LGL cells. The more frequent CD3+ cases may be related to recently described NK-like T cells. The observations that normal LGLs maintain germline T gamma genes and that many CD3+ T gamma LPD display an alpha/beta heterodimer suggest that a T gamma-containing receptor may not be necessary for NK or NK-like cytotoxicity.
 ...
PMID:T cell receptor (alpha, beta, gamma) gene rearrangements and expression in normal and leukemic large granular lymphocytes/natural killer cells. 244 90

Using the non-crossreactive mAb MRC-OX3 and MRC-OX6, two serologically distinct RT1.B-specific (I-A equivalent) alpha, beta heterodimers have previously been described by us as residing at the cell surface of LEW rat spleen cells. The two-chain elements were suggested to represent stable conformation isomers, diverged by dissociation of the mature gamma-chain from a mAb MRC-OX6 reactive biosynthetic intermediate, composed of terminally glycosylated alpha-, beta- and gamma-chains. In this study we addressed the question of whether or not the presence of terminally glycosylated invariant gamma-chain was obligatory for the formation of the two MRC-OX3 and MRC-OX6 reactive two-chain complexes. The synthesis of RT1.B-specific alpha, beta heterodimers was therefore initiated, in the absence of accompanying invariant gamma-chains, by microinjecting hybrid-selected RT1.B alpha- and beta-specific mRNA into oocytes of Xenopus laevis for translation. Class II molecules produced were analyzed by affinity chromatography of radioactive-labeled oocyte detergent lysates using the appropriate monoclonal immunoadsorbents for identification. Although rat gamma-chain mRNA was excluded in this assay system, distinct MRC-OX3 and MRC-OX6 reactive two-chain complexes were detected by two-dimensional gel electrophoresis. These findings clearly indicate that the formation of the two RT1.B-specific alpha, beta heterodimers is independent of the presence of the rat invariant gamma-chain.
Mol Immunol 1989 Feb
PMID:Translation in Xenopus laevis oocytes of hybrid selected LEW rat RT1.B alpha- and beta-chain transcripts results in serologically discrete class II polypeptide chain complexes. 246 90

Several analogues of 2',3'-dideoxythymidine 5'-triphosphate [i.e., 3'-azido-2', 3'-dideoxythymidine 5'-triphosphate(Azdd TTP), 2',3'-didehydro-2',3'-dideoxythymidine 5'-triphosphate (ddeTTP), alpha, beta-methylene 3'-azido-2',3'-dideoxythymidine 5'-diphosphate, alpha, beta-methylene 3'-azido-2',3'-dideoxythymidine 5'-triphosphate, and beta, gamma-methylene 3'-azido-2',3'-dideoxythymidine 5'-triphosphate] and 2',3'-didehydro-2',3'-dideoxycytidine 5'-triphosphate (ddeCTP) have been evaluated for their inhibitory effects on murine retroviral reverse transcriptase and various other DNA polymerases, including DNA polymerases alpha, beta, and gamma, terminal deoxynucleotidyl transferase, and DNA polymerase I. None of the compounds inhibited the activity of DNA polymerase alpha under the reaction conditions employed. When Mg2+ was replaced by Mn2+, however, DNA polymerase alpha was strongly inhibited only by ddeTTP. DNA polymerase beta activity was inhibited only by ddeTTP and ddeCTP. All the compounds, except for ddeCTP, inhibited DNA polymerase gamma activity, ddeTTP being a particularly strong inhibitor of gamma-polymerase (Ki = 3.5 nM). Terminal deoxynucleotidyl transferase was only slightly inhibited by any of the compounds. AzddTTP was a potent inhibitor of reverse transcriptase (Ki = 42 nM), but it also inhibited the activities of DNA polymerase gamma and DNA polymerase I.
Mol Pharmacol 1989 May
PMID:Differential inhibitory effects of several pyrimidine 2',3'-dideoxynucleoside 5'-triphosphates on the activities of reverse transcriptase and various cellular DNA polymerases. 247 Oct 54

We have analyzed the RNA expression of three protein kinase C (PKC) genes (alpha, beta, and gamma) in human and murine central nervous systems during embryonic-fetal, perinatal, and adult life. Analysis of human brain poly(A)+ RNA indicates that expression of PKC alpha and beta genes can be detected as early as 6 weeks postconception, undergoes a gradual increase until 9 weeks postconception, and reaches its highest level in the adult stage, and that the PKC gamma gene, although not expressed during embryonic and early fetal development, is abundantly expressed in the adult period. Similar developmental patterns were observed in human spinal cord and medulla oblongata. A detailed analysis of PKC gene expression during mammalian ontogeny was performed on poly(A)+ RNA from the brain cells of murine embryos at different stages of development and the brain cells of neonatal and adult mice. The ontogenetic patterns were similar to those observed for human brain. Furthermore, we observed that the expression of PKC gamma is induced in the peri- and postnatal phases. These results suggest that expression of PKC alpha, beta, and gamma genes possibly mediates the development of central neuronal functions, and expression of PKC gamma in particular may be involved in the development of peri- and postnatal functions.
Mol Cell Biol 1989 May
PMID:Expression of protein kinase C genes during ontogenic development of the central nervous system. 247 91

Two forms of inhibin (A and B), gonadal polypeptide hormones that selectively suppress the secretion of FSH from the anterior pituitary, have been characterized from the porcine and human species, each being composed of a common alpha-chain and one of two distinct, but homologous beta-chains, i.e. alpha beta A and alpha beta B. Using cDNAs encoding the porcine inhibin subunits we have cloned and sequenced the cDNAs encoding the alpha, beta A, and beta B chains of rat ovarian inhibin. Northern analyses of rat testicular RNA with rat ovarian cDNA probes show the presence of mRNAs encoding alpha and beta B chains, but no detectable mRNA encoding the beta A chain under our experimental conditions. This suggests that there may be specific and distinct physiological roles for inhibins A and B. In addition, if there is no extratesticular source of beta A mRNA, then the male rat may be devoid of the stimulators of the secretion of FSH, i.e. activin (beta A beta B) and homoactivin A (beta A beta A), which are derived from the beta subunits of the two inhibins.
Mol Endocrinol 1987 May
PMID:Complementary deoxyribonucleic acid (cDNA) cloning and DNA sequence analysis of rat ovarian inhibins. 248 14


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