Abstract
AlF4- has long been known to associate with and activate the GDP-bound alpha subunits of heterotrimeric G-proteins. Recently the small guanine nucleotide binding protein Ras has also been shown to associate with AlF4- in the presence of stoichiometric amounts of its GTPase activating protein (GAP). Here we present the isolation of a stable Ras x GDP- x AlF4- x GAP ternary complex by gel filtration. In addition, we generalise the association of AlF4- with the small GTP-binding proteins by demonstrating ternary complex formation for the Cdc42, Rap and Ran proteins in the presence of their respective GAP proteins.
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Fluoride stimulates in vitro vascular prostacyclin synthesis: interrelationship of G proteins and protein kinase C
The role of G proteins in mediating adrenoceptor-prostacyclin synthesis coupling was investigated using the G protein activator, sodium fluoride. Sodium fluoride (NaF) stimulated in vitro rat aortic prostacyclin (PGI2) synthesis (EC50 = 5 x 10(-3) mol.l-1), an action inhibited completely by the presence of EDTA (10(-2) mol.l-1). The NaF-PGI2 dose-response
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Predominant contribution of the G protein-mediated mechanism to NaF-induced vascular contractions in diabetic rats: association with an increased level of G(qalpha) expression.
The purpose of this study was to determine the mechanism responsible for alterations in NaF-induced contractions of blood vessels from streptozotocin-induced diabetic rats. In the presence of AlCl(3), NaF (>/=7.5 mM) produced significantly greater contractions in diabetic aorta and mesenteric artery compared with age-matched controls. Pretreatment with 1 microM nifedipine
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Phosphatidylinositol 4,5-bisphosphate hydrolysis accompanies T cell receptor-induced apoptosis of murine thymocytes within the thymus.
Regulation of the development of thymocytes into mature T cells within the thymus is now known to involve antigen-induced deletion, by apoptosis, of potentially autoreactive thymocytes, and it can be mimicked either by stimulating the T cell receptor (TcR) complex by monoclonal antibody (mAb) or by ionophore-induced elevation of cytosolic
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Fluoride toxicity in the male reproductive system
This review covers the current scientific understanding of the links between environmental exposure to fluoride (F) and its known or potential effects on human male fertility. The most important consequences of these F exposures are: changes in the structure and functional behavior of spermatozoa, disruption of spermatogenesis, and disturbances of
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De novo expression of the class-A macrophage scavenger receptor conferring resistance to apoptosis in differentiated human THP-1 monocytic cells.
The class-A macrophage scavenger receptor (MSR) is a trimeric multifunctional protein expressed selectively in differentiated monomyeloid phagocytes which mediates uptake of chemically modified lipoproteins and bacterial products. This study investigated whether MSR plays a role in the regulation of apoptosis, a model of genetically programmed cell death. De novo expression
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