Search results for "AS2"

Respiration and low cAMP-dependent protein kinase activity are required for high-level expression of the peroxisomal thiolase gene in Saccharomyces c…

1996

Transcription of genes for peroxisomal proteins is repressed by glucose and induced by oleate. At least for the peroxisomal thiolase gene (POT1) there is a third regulatory mechanism, mediated by the transcription factor Adr1p, which is responsible for the high-level expression of the gene in stationary phase. Here we show that a region in the POT1 promoter that extends from positions -238 to -152 mediates this mechanism, and we suggest that Adr1p acts indirectly on POT1. We have also analyzed the role of the cAMP-dependent protein kinase (PKA) in the transcriptional regulation of POT1. PKA exerts a negative control: the high, unregulated PKA activity in a bcy1 mutant maintains POT1 transcr…

Direct Identification of Each Specific Mutation in Codon 12 and 13 of ci-ki-ras2 by SSCP Analysis

1998

We compared the SSCP behaviour of the DNA fragments containing c-ki-ras 2 wild type 12 and 13 codons or each of the 12 possible point mutated sequences in these two codons. We found that a single electrophoresis condition was sufficient to distinguish each specific mutation from the other 11 and from the wild type sequence. This observation makes it possible to identify each specific mutation directly by SSCP without any need for reamplification and sequencing.

Role of glycine-82 as a pivot point during the transition from the inactive to the active form of the yeast Ras2 protein

1991

AbstractRas proteins bind either GDP or GTP with high affinity. However, only the GTP-bound form of the yeast Ras2 protein is able to stimulate adenylyl cyclase. To identify amino acid residues that play a role in the conversion from the GDP-bound to the GTP-bound state of Ras proteins, we have searched for single amino acid substitutions that selectively affected the binding of one of the two nucleotides. We have found that the replacement of glycine-82 of the Ras2 protein by serine resulted in an increased rate of dissociation of Gpp(NH)p, a nonhydrolysable analog of GTP, while the GDP dissociation rate was not significantly modified. Glycine-82 resides in a region that is highly conserve…

Energetic aspects of intramolecular coupling between the nucleotide binding site and the distal switch II region of the yeast RAS2 protein

1994

AbstractWe have studied the interaction of the yeast RAS2 protein with guanine nucleotides using energetic parameters for the dissociation of RAS·nucleotide complexes. The results indicated that a Gly → Ser substitution at position 82 led to an altered interaction with GppNHp and, to a lesser extent, also with GDP. It was also possible to conclude that structural perturbation of Gly82 can stimulate nucleotide release by decreasing the energetic barrier for nucleotide dissociation. This, together with the observation that residues 80 and 81 are involved in the response of RAS to nucleotide exchange factors without affecting GDP binding per se, suggests a potential mechanism for exchange fact…

Phosphorylation of an Overexpressed Yeast Ras2 Protein During the G1 Phase of the Cell Cycle

1994

RAS proteins regulate growth and differentiation in evolutionarily distant systems such as vertebrates and yeast (for reviews, see Tamanoi, 1988; Gibbs and Marshall, 1989; Broach and Deschenes, 1990). At the moleular level, a key function of the yeast RAS1 and RAS2 proteins (collectively referred to as RAS) is to positively regulate the production of cyclic AMP at the onset of the G1 phase of the cell cycle (Toda et al., 1985; De Vendittis et al., 1986). At this stage, RAS proteins are transiently activated by the noncovalent binding of a GTP molecule. Reversal of the effect occurs by the hydrolytic splitting of the ’γ-phosphate of GTP, that leaves a functionally inactive RASGDP complex, th…

Genetic polymorphism of the bitter taste TAS2R38 gene in central Sicily

2007

Bitter taste genetics and food preference in italian population

2010

Objective: To investigate the possible role of the polymorphic bitter taste gene, TAS2R38, known to be involved in the perception of the bitter synthetic chemical phenylthiocarbamide (PTC), in influencing food preference and body mass index(BMI). Methods: up to now more than 1500 university students (17-25 years old) at Catania, Cosenza, Rome, Palermo, Pisa, Parma, Chieti, Trento University have been enrolled in the study. DNA was extracted from saliva, and genotyped by TaqMan assay for the most frequent polymorphism (PAV/AVI) of TAS2R38 gene. A possible association between genotype and food preference was assessed by administering a detailed questionnaire for food preferences and life styl…

SNP variation in the bitter taste TAS2R38 gene evaluated in student populations of several italian universities and isolates

2007

People vary widely in their sensitivities to bitter compounds, but the all intercorrelation of these sensitivities is unknown. The study of genetic influences on bitter taste perception originated from the discovery in the 1930s that some individuals had taste to phenylthiocarbamide(PTC), whereas others found it extremely bitter. Subsequently, many studies were carried out on PTC and the structurally related compound propylthiouracil (PROP) to assess this viability and to determine the root causes. Initial family studies strongly suggested that PTC no tasting was due to a recessive allele in a single gene and heritability was estimated at 0,5. 55-85% of variation in PTC detection. The PTC ge…

Real-world evidence of biologic treatments in psoriatic arthritis in Italy: results of the CHRONOS (EffeCtiveness of biologic treatments for psoriati…

2022

Abstract Background Biologics have demonstrated efficacy in PsA in randomized clinical trials. More evidence is needed on their effectiveness under real clinical practice conditions. The aim of the present work is to provide real-world evidence of the effectiveness of biologics for PsA in the daily clinical practice. Methods CHRONOS was a multicenter, non-interventional, cohort study conducted in 20 Italian hospital rheumatology clinics. Results 399 patients were eligible (56.9% females, mean (SD) age: 52.4 (11.6) years). The mean (SD) duration of PsA and psoriasis was 7.2 (6.9) and 15.3 (12.2) years, respectively. The mean (SD) duration of the biologic treatment under analysis was 18.6 (6.…

Saveur amère : de la molécule au comportement

2020

La saveur amère permet aux mammifères d’éviter l’ingestion d’aliments poten-tiellement contaminés par des substances amères toxiques fréquemment retrouvées dans notre environnement. La détection de ces molécules aux structures chimiques diverses est réalisée par une famille de récepteurs appelés TAS2R. L’être humain est pourvu de 25 TAS2R aux spectres de reconnaissance plus ou moins larges pour détecter un grand nombre de molécules amères. Des tests fonctionnels in vitro ont été développés afin de détermi-ner le profil d’activation des TAS2R humains. De nombreuses molécules, d’origines natu-relles ou synthétiques ont pu être identifiées comme capable d’activer ces TAS2R. Ces tests fonctionn…