phosphorus-radioisotopes and tetrafluoroaluminate

phosphorus-radioisotopes has been researched along with tetrafluoroaluminate* in 2 studies

Other Studies

2 other study(ies) available for phosphorus-radioisotopes and tetrafluoroaluminate

Article	Year
Activators of protein kinase A decrease the levels of free arachidonic acid in osteoblasts via stimulation of phosphatidylcholine and phosphatidylethanolamine synthesis. Prostaglandins, leukotrienes, and essential fatty acids, 1998, Volume: 58, Issue:2 In order to examine the role of protein kinase A (PKA) in the regulation of arachidonic acid availability, the interaction between cAMP agonists and the G protein activator AIF4- in their effects on phospholipid metabolism were measured in MC3T3-E1 osteoblasts. We show that forskolin and 8-brcAMP, activators of PKA, amplify the AIF4(-)-induced stimulation of phosphatidylinositol-specific phospholipase C (phosphatidylinositol inositolphosphohydrolase; EC 3.1.4.3), measured by the formation of [3H]inositol phosphates in prelabeled cells. However, the AIF4(-)-stimulated production of 1,2-diacylglycerols and the release of [3H]arachidonic acid ([3H]AA) were inhibited 50-75% by forskolin and 8-bromocAMP. Furthermore, pretreatment with PKA activators prevented much of the AIF4(-)-induced loss of [3H]AA from phosphatidylcholine and phosphatidylethanolamine in prelabeled osteoblasts. In addition, in the absence of AIF4-, forskolin was found to stimulate the incorporation of [3H]AA and [32P]orthophosphoric acid selectively into these two major phospholipids and selectively increased their mass. The effects of forskolin and 8-BrcAMP on the levels of free [3H]AA were completely reversed by pretreatment with the PKA inhibitor H-89. Therefore, our findings suggest that the activation of cAMP-dependent protein kinase can reduce the availability of free arachidonic acid for prostaglandin synthesis in osteoblast cells by stimulating its reesterification via phospholipid resynthesis. Topics: Aluminum Compounds; Animals; Arachidonic Acid; Cell Line; Cyclic AMP-Dependent Protein Kinases; Diglycerides; Enzyme Activation; Fatty Acids; Fluorides; Osteoblasts; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Phosphoric Acids; Phosphorus Radioisotopes; Tritium	1998
Mechanism of GTP hydrolysis by G-protein alpha subunits. Proceedings of the National Academy of Sciences of the United States of America, 1994, Oct-11, Volume: 91, Issue:21 Hydrolysis of GTP by a variety of guanine nucleotide-binding proteins is a crucial step for regulation of these biological switches. Mutations that impair the GTPase activity of certain heterotrimeric signal-transducing G proteins or of p21ras cause tumors in man. A conserved glutamic residue in the alpha subunit of G proteins has been hypothesized to serve as a general base, thereby activating a water molecule for nucleophilic attack on GTP. The results of mutagenesis of this residue (Glu-207) in Gi alpha 1 refute this hypothesis. Based on the structure of the complex of Gi alpha 1 with GDP, Mg2+, and AlF-4, which appears to resemble the transition state for GTP hydrolysis, we believe that Gln-204 of Gi alpha 1, rather than Glu-207, supports catalysis of GTP hydrolysis by stabilization of the transition state. Topics: Aluminum Compounds; Amino Acid Sequence; Base Sequence; Conserved Sequence; DNA; Escherichia coli; Fluorides; GTP Phosphohydrolases; GTP-Binding Proteins; Guanosine 5'-O-(3-Thiotriphosphate); Guanosine Triphosphate; Humans; Hydrolysis; Kinetics; Macromolecular Substances; Magnesium; Molecular Sequence Data; Mutagenesis, Site-Directed; Oligodeoxyribonucleotides; Phosphorus Radioisotopes; Proto-Oncogene Proteins p21(ras); Recombinant Proteins; Signal Transduction; Time Factors	1994

Article

Year

Activators of protein kinase A decrease the levels of free arachidonic acid in osteoblasts via stimulation of phosphatidylcholine and phosphatidylethanolamine synthesis.

Prostaglandins, leukotrienes, and essential fatty acids, 1998, Volume: 58, Issue:2

In order to examine the role of protein kinase A (PKA) in the regulation of arachidonic acid availability, the interaction between cAMP agonists and the G protein activator AIF4- in their effects on phospholipid metabolism were measured in MC3T3-E1 osteoblasts. We show that forskolin and 8-brcAMP, activators of PKA, amplify the AIF4(-)-induced stimulation of phosphatidylinositol-specific phospholipase C (phosphatidylinositol inositolphosphohydrolase; EC 3.1.4.3), measured by the formation of [3H]inositol phosphates in prelabeled cells. However, the AIF4(-)-stimulated production of 1,2-diacylglycerols and the release of [3H]arachidonic acid ([3H]AA) were inhibited 50-75% by forskolin and 8-bromocAMP. Furthermore, pretreatment with PKA activators prevented much of the AIF4(-)-induced loss of [3H]AA from phosphatidylcholine and phosphatidylethanolamine in prelabeled osteoblasts. In addition, in the absence of AIF4-, forskolin was found to stimulate the incorporation of [3H]AA and [32P]orthophosphoric acid selectively into these two major phospholipids and selectively increased their mass. The effects of forskolin and 8-BrcAMP on the levels of free [3H]AA were completely reversed by pretreatment with the PKA inhibitor H-89. Therefore, our findings suggest that the activation of cAMP-dependent protein kinase can reduce the availability of free arachidonic acid for prostaglandin synthesis in osteoblast cells by stimulating its reesterification via phospholipid resynthesis.

Topics: Aluminum Compounds; Animals; Arachidonic Acid; Cell Line; Cyclic AMP-Dependent Protein Kinases; Diglycerides; Enzyme Activation; Fatty Acids; Fluorides; Osteoblasts; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Phosphoric Acids; Phosphorus Radioisotopes; Tritium

1998

Mechanism of GTP hydrolysis by G-protein alpha subunits.

Proceedings of the National Academy of Sciences of the United States of America, 1994, Oct-11, Volume: 91, Issue:21

Hydrolysis of GTP by a variety of guanine nucleotide-binding proteins is a crucial step for regulation of these biological switches. Mutations that impair the GTPase activity of certain heterotrimeric signal-transducing G proteins or of p21ras cause tumors in man. A conserved glutamic residue in the alpha subunit of G proteins has been hypothesized to serve as a general base, thereby activating a water molecule for nucleophilic attack on GTP. The results of mutagenesis of this residue (Glu-207) in Gi alpha 1 refute this hypothesis. Based on the structure of the complex of Gi alpha 1 with GDP, Mg2+, and AlF-4, which appears to resemble the transition state for GTP hydrolysis, we believe that Gln-204 of Gi alpha 1, rather than Glu-207, supports catalysis of GTP hydrolysis by stabilization of the transition state.

Topics: Aluminum Compounds; Amino Acid Sequence; Base Sequence; Conserved Sequence; DNA; Escherichia coli; Fluorides; GTP Phosphohydrolases; GTP-Binding Proteins; Guanosine 5'-O-(3-Thiotriphosphate); Guanosine Triphosphate; Humans; Hydrolysis; Kinetics; Macromolecular Substances; Magnesium; Molecular Sequence Data; Mutagenesis, Site-Directed; Oligodeoxyribonucleotides; Phosphorus Radioisotopes; Proto-Oncogene Proteins p21(ras); Recombinant Proteins; Signal Transduction; Time Factors

1994