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Cyclase

About: Cyclase is a research topic. Over the lifetime, 10162 publications have been published within this topic receiving 388566 citations.


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Book ChapterDOI
TL;DR: The function of RAS genes in the yeast Saccharomyces cerevisiae and the components of the pathway in which it acts are described, showing that RAS1 and RAS2 are functionally interchangeable for growth in rich medium.
Abstract: Publisher Summary This chapter describes the function of RAS genes in the yeast Saccharomyces cerevisiae and the components of the pathway in which it acts. Yeast RAS proteins share considerable homology with the mammalian RAS proteins. A short sequence including an invariant cysteine residue is always found at the carboxyl end of all RAS proteins. Deletion of either RAS1 or RAS2 alone has no deleterious effects on the growth of yeast strains in rich media, while deletion of both the genes is lethal. This shows that RAS1 and RAS2 are functionally interchangeable for growth in rich medium. Purified adenylate cyclase can be stimulated by purified RAS protein in vitro. The purified RAS2 protein can be phosphorylated in vitro by mammalian A kinase and the phosphorylated RAS protein is ∼2-fold less active in stimulating adenylate cyclase in vitro than is dephosphorylated protein. In addition, both RAS1 and RAS2 proteins are phosphorylated in vivo.

204 citations

Journal ArticleDOI
11 Mar 1976-Nature
TL;DR: The results indicate that the actions of histamine on H2 receptors in the CNS may be mediated through cyclic AMP.
Abstract: THERE is increasing interest in the possibility that histamine may be a neurotransmitter in the mammalian central nervous system (CNS). Electrophysiological evidence supports the existence of histamine receptors in nervous tissue through which neuronal excitability can be regulated. For example, the firing rate of certain neurones in the brain is depressed by histamine and this depression is specifically blocked by the H2 antagonist, metiamide1. In addition, histamine influences the electrical excitability of neurones in the superior cervical ganglion2. Certain neurotransmitters may exert some of their effects in nervous tissue by stimulating the formation of cyclic AMP. It is therefore of interest that histamine raises cyclic AMP levels in brain slices3–7, as do several other putative neurotransmitters, such as noradrenaline, dopamine and 5-hydroxytryptamine (5-HT). Furthermore, a dopamine-sensitive adenylate cyclase has been found in homogenates of rat caudate nucleus and olfactory tubercle, with properties very similar to those of the dopamine receptor in mammalian brain8–10. We report here the occurrence of an adenylate cyclase which is activated by low concentrations of histamine in several regions of guinea pig brain. This histamine-sensitive adenylate cyclase has the pharmacological properties of an H2 receptor. The results indicate that the actions of histamine on H2 receptors in the CNS may be mediated through cyclic AMP.

203 citations

Journal ArticleDOI
TL;DR: While additional proteins may modulate adenylate cyclase activity in native membranes, these results show that these three proteins are sufficient for the expression of hormone-stimulatedadenylates cyclase.

203 citations

Journal ArticleDOI
TL;DR: It was concluded that the beta-adrenergic receptor of the turkey erythrocytes must have become functionally coupled to the adenylate cyclase of the mouse F cells and it is proposed that the procedure of massive heterologous cell fusion can be used to analyze the function of other cell membrane components.
Abstract: The experiments test the hypothesis that beta-adrenergic receptor is an independent unit that can be transferred from one adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4-6-1-1[ system to another. Turkey erythrocytes in which the catalytic activity of adenylate cyclase had been inactivated by N-ethylmaleimide or by heat contributed the beta-adrenergic receptor. Friend erythroleukemia cells (F cells) that possessed no measurable beta-adrenergic receptor contributed the adenylate cyclase. The erythrocytes in which the enzyme had been inactivated were fused with the F cells by Sendai virus. The cell ghosts of the fused preparation demonstrated adenylate cyclase activity which was strikingly enhanced by isoproterenol. Controls of fusion of F cells with each other or with human erythrocytes failed to show a response to isoproterenol. It was therefore concluded that the beta-adrenergic receptor of the turkey erythrocytes must have become functionally coupled to the adenylate cyclase of the mouse F cells. Activation by isoproterenol was demonstrable within a few minutes after fusion, and inhibitors of protein synthesis had no effect. Thus, coupling must have occurred between the preexisting components. The findings suggest that it may be possible in the future to confer on cells that possess an adenylate cyclase system new hormonal responses by inserting a receptor into their cell membrane. It is proposed that the procedure of massive heterologous cell fusion, as used in the present study, can be used to analyze the function of other cell membrane components.

203 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202324
202257
202145
202048
201939
201856