Search results for "Phosphor"
showing 10 items of 1952 documents
Phosphorylation of the Usher syndrome 1G protein SANS controls Magi2-mediated endocytosis.
2014
Item does not contain fulltext The human Usher syndrome (USH) is a complex ciliopathy with at least 12 chromosomal loci assigned to three clinical subtypes, USH1-3. The heterogeneous USH proteins are organized into protein networks. Here, we identified Magi2 (membrane-associated guanylate kinase inverted-2) as a new component of the USH protein interactome, binding to the multifunctional scaffold protein SANS (USH1G). We showed that the SANS-Magi2 complex assembly is regulated by the phosphorylation of an internal PDZ-binding motif in the sterile alpha motif domain of SANS by the protein kinase CK2. We affirmed Magi2's role in receptor-mediated, clathrin-dependent endocytosis and showed tha…
Oxidative stress in environmental-induced carcinogenesis.
2009
Reactive oxygen species (ROS) are the more abundant free radicals in nature and have been related with a number of tissue/organ injuries induced by xenobiotics, ischemia, activation of leucocytes, UV exposition, etc. Oxidative stress is caused by an imbalance between ROS production and a biological system's ability to readily detoxify these reactive intermediates or easily repair the resulting damage. Thus, oxidative stress is accepted as a critical pathophysiological mechanism in different frequent human pathologies, including cancer. In fact ROS can cause protein, lipid, and DNA damage, and malignant tumors often show increased levels of DNA base oxidation and mutations. Different lifesty…
Characterization of aging-associated up-regulation of constitutive nuclear factor-kappa B binding activity.
2001
Changes occur in gene expression during aging in vivo and in replicative senescence in vitro, suggesting that aging can affect gene regulation. We have recently observed age-related changes in ubiquitously expressed, oxidative stress-responsive nuclear factor-kappa B (NF-kappa B) pathway during aging. Here we report a significant age-related increase in nuclear NF-kappa B binding activity together with increased protein levels of p52 and p65 components in rat liver. An additional, higher molecular weight protein band seen in their western blots suggests that their post-translational modification (but not phosphorylation) occurs in liver, which might affect their nuclear localization and bin…
Overexpression of apolipoprotein J in human fibroblasts protects against cytotoxicity and premature senescence induced by ethanol and tert-butylhydro…
2008
Human diploid fibroblasts (HDFs) exposed to subcytotoxic stresses under H2O2, tert-butylhydroperoxide (t-BHP), and ethanol (EtOH) undergo stress-induced premature senescence (SIPS) characterized by many biomarkers of HDFs replicative senescence. Among these biomarkers are a growth arrest, an increase in the senescence-associated β-galactosidase activity, a senescent morphology, an overexpression of p21waf-1 and the subsequent inability to phosphorylate pRb, the presence of the common 4977-bp mitochondrial deletion, and an increase in the steady-state level of several senescence-associated genes such as apolipoprotein J (apo J). Apo J has been described as a survival gene against cytotoxic s…
DNA damage causes TP53-dependent coupling of self-renewal and senescence pathways in embryonal carcinoma cells.
2013
Recent studies have highlighted an apparently paradoxical link between self-renewal and senescence triggered by DNA damage in certain cell types. In addition, the finding that TP53 can suppress senescence has caused a re-evaluation of its functional role in regulating these outcomes. To investigate these phenomena and their relationship to pluripotency and senescence, we examined the response of the TP53-competent embryonal carcinoma (EC) cell line PA-1 to etoposide-induced DNA damage. Nuclear POU5F1/OCT4A and P21CIP1 were upregulated in the same cells following etoposide-induced G 2M arrest. However, while accumulating in the karyosol, the amount of OCT4A was reduced in the chromatin fract…
Attenuation of NF-κB Signaling Response to UVB Light during Cellular Senescence
1999
The ability of cells to adapt to environmental stresses undergoes a progressive reduction during aging. NF-kappaB-mediated signaling is a major defensive system against various environmental challenges. The aim of this study was to find out whether replicative senescence affects the response of the NF-kappaB signaling pathway to UVB light in human WI-38 and IMR-90 fibroblasts. The exposure of early passage fibroblasts to UVB light inhibited the proliferation and induced a flat phenotype similar to that observed in replicatively senescent fibroblasts not exposed to UVB light. The UVB radiation dose used (153 mJ/cm2) did not induce apoptosis in either early or late passage WI-38 fibroblasts. …
NECAB2 participates in an endosomal pathway of mitochondrial stress response at striatal synapses
2021
Synaptic signaling depends on ATP generated by mitochondria. Due to extensive connectivity, the striatum is especially vulnerable to mitochondrial dysfunction and thus requires efficient mitochondrial quality control. We found that the neuronal calcium-binding protein NECAB2 ensures synaptic function in the striatum by increasing mitochondrial efficiency. NECAB2 associates with early endosomes and mitochondria at striatal synapses. Loss of NECAB2 dysregulates proteins of the endosomal ESCRT machinery and oxidative phosphorylation. Mitochondria from NECAB2-deficient mice are more abundant but less efficient. These mitochondria exhibit increased respiration and superoxide production but produ…
The nucleotide and partial amino acid sequences of rat fetuin. Identity with the natural tyrosine kinase inhibitor of the rat insulin receptor.
1992
Fetuins are among the major plasma proteins, yet their biological role has remained elusive. Here we report the molecular cloning of rat fetuin and the sequence analysis of a full-length clone, RF619 of 1456 bp with an open reading frame of 1056 bp encoding 352 amino acid residues. The coding part of RF619 was identical with the cDNA sequence of the natural inhibitor of the insulin receptor tyrosine kinase from rat (pp63) except for four substitutions and a single base insertion causing divergence of the predicted protein sequences. Partial amino acid sequences of rat plasma fetuin were in agreement with the predictions based on the RF619 cDNA. Purified rat fetuin inhibited the insulin rece…
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…
Thermal degradation of microcrystalline cellulose in concentrated phosphoric acid
2011
The most common renewable fuel is ethanol. It is a liquid produced by fermentation of glucose which is very abundant in cellulose based materials. Bioethanol is achieved in a two-steps process: 1. hydrolysis of the cellulose included in the ligno-cellulosic materials to fermentable reducing sugars; 2. fermentation of such sugars to ethanol. While the second fermentation step, mediated by yeasts or bacteria, is very well established, the first one must be still assessed for process optimization. Many efforts have been made to identify solvents for cellulose in order to develop methods for the achievement of fermentable glucose. In the presence of mineral acid, cellulose undergoes hydrolysis …