Abstract
Fluoride activation of the cGMP cascade of vision requires the presence of aluminum, and is shown to be mediated by the binding of one A1F-4 to the GDP/GTP-binding subunit of transducin. The presence of GDP in the site is required: A1F-4 is ineffective when the site is empty or when GDP beta S is substituted for GDP. This sensitivity to the sulfur of GDP beta S suggests that A1F-4 is in contact with the GDP. Striking structural similarities between A1F-4 and PO3-4 lead us to propose that A1F-4 mimics the role of the gamma-phosphate of GTP.
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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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Fluoride: mode of action.
Conclusions and Perspectives The results obtained so far on the cellular mechanism by which fluoride may influence the growth and differentiation of osteoblastic cell lines strongly suggest alteration of one or several G protein-dependent tyrosine phosphorylation process(es), activation of the ERK, and possibly other signaling pathways. There is a controversy 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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The biochemistry and physiology of metallic fluoride: action, mechanism, and implications
Fluoride is a well-known G protein activator. Activation of heterotrimeric GTP-binding proteins by fluoride requires trace amounts of Al3+ or Be2+ ions. AlFx mimics a gamma-phosphate at its transition state in a Galpha protein and is therefore able to inhibit its GTPase activity. AlFx also forms complexes with small GTP-binding
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Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride.
In enamel fluorosis model rats treated with sodium fluoride, secretory ameloblasts of incisor tooth germs exhibited disruption of intracellular trafficking. We examined whether heterotrimeric G proteins participated in the disruption of vesicular trafficking of the secretory ameloblast exposed to fluoride, using immunoblotting and pertussis toxin (IAP)-induced adenosyl diphosphate (ADP)-ribosylation for
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