Search results for " Localization"

Interaction of Au16 Nanocluster with Defects in Supporting Graphite: A Density-Functional Study

2011

Soft-landed adsorption of Au-16 on bilayered graphene is investigated using density functional theory. The orientation of the Au-16 cluster and number of neighboring surface vacancies affect the overall structural and electronic properties of the cluster. The results of the PBE, vdW-DF, and vdW-DF2 exchange-correlation functionals are compared for the cluster-substrate interaction for systems with and without defects. In the presence of defects size two and greater, an Au atom adsorbs into the topmost graphene layer; this strongly influences the binding energy (>3 eV), while inducing substantial bending in the carbon plane and altering electronic properties of the system. Though the T-d-sym…

Phosphorylation of cytochromes P450: First discovery of a posttranslational modification of a drug-metabolizing enzyme

2005

Cytochromes P450 (CYP) are important components of xenobiotic-metabolizing monooxygenases (CYP-dependent monooxygenases). Their regulation by induction, most commonly by transcriptional activation, mediated by xenobiotics, normally substrates of the corresponding CYP, is well known and has been widely studied. Our team has discovered an additional important regulation of xenobiotic-metabolizing CYPs pertaining to posttranslational modification by phosphorylation. Individual CYPs are phosphorylated by different protein kinases, leading to CYP isoenzyme-selective changes in the metabolism of individual substrates and consequent drastic changes in the control of genotoxic metabolites. Best stu…

Unravelling the Mysteries of the [3+2] Cycloaddition Reactions

2018

Resolving Binding Events on the Multifunctional Human Serum Albumin

2020

Abstract Physiological processes rely on initial recognition events between cellular components and other molecules or modalities. Biomolecules can have multiple sites or mode of interaction with other molecular entities, so that a resolution of the individual binding events in terms of spatial localization as well as association and dissociation kinetics is required for a meaningful description. Here we describe a trichromatic fluorescent binding‐ and displacement assay for simultaneous monitoring of three individual binding sites in the important transporter and binding protein human serum albumin. Independent investigations of binding events by X‐ray crystallography and time‐resolved dyn…

Cannabinoid control of brain bioenergetics: Exploring the subcellular localization of the CB1 receptor

2014

Brain mitochondrial activity is centrally involved in the central control of energy balance. When studying mitochondrial functions in the brain, however, discrepant results might be obtained, depending on the experimental approaches. For instance, immunostaining experiments and biochemical isolation of organelles expose investigators to risks of false positive and/or false negative results. As an example, the functional presence of cannabinoid type 1 (CB1) receptors on brain mitochondrial membranes (mtCB1) was recently reported and rapidly challenged, claiming that the original observation was likely due to artifact results. Here, we addressed this issue by directly comparing the procedures…

Nucleon localization function in rotating nuclei

2020

Background: An electron localization function was originally introduced to visualize bond structures in molecules. It became a useful tool to describe electron configurations in atoms, molecules and solids. In nuclear physics, a nucleon localization function (NLF) has been used to characterize clusters in light nuclei, fragment formation in fission and pasta phases in the inner crust of neutron stars. Purpose: We use the NLF to study the nuclear response to fast rotation. Methods: We generalize the NLF to the case of nuclear rotation. The extended expressions involve both time-even and time-odd local densities. Since current density and density gradient contribute to the NLF primarily at th…

Bovine seminal ribonuclease is cytotoxic for both malignant and normal telomerase-positive cells

2005

Bovine seminal-ribonuclease (BS-RNase) is a member of the 'ribonucleases with special biological actions' family since it possesses specific anti-tumour, anti-spermatogenic and embryotoxic activities and exerts an immunosuppressive effect on T lymphocytes. In previous studies it was demonstrated that BS-RNase induced apoptosis in proliferating, malignant and normal cells and that telomerase activity loss also caused apoptotic death in neoplastic cells. Since an obvious relationship between cell proliferation and telomerase activity exists, the aim of this work was to study if the pro-apoptotic cytotoxic action exerted by BS-RNase on proliferating malignant cells (HT29) and proliferating nor…

Loss of tumor suppressor protein PTEN during renal carcinogenesis

2002

The tumor suppressor gene PTEN (phosphatase and tensin homologue deleted from chromosome 10) encodes a dual specific protein and phospholipid phosphatase that affects cell proliferation, apoptosis and migration. In our study, we examined protein expression of PTEN in renal carcinogenesis. PTEN protein levels were examined in 42 clear cell renal cell carcinomas (ccRCC) and oncocytomas as well as in the corresponding normal renal tissue of the same patients using Western blot analysis. Cellular localization was analyzed by immunohistochemistry. PTEN was highly expressed in all investigated normal renal tissue specimens. Immunohistochemical analysis showed an almost exclusive staining of proxi…

aPKCζ cortical loading is associated with Lgl cytoplasmic release and tumor growth in Drosophila and human epithelia

2007

Atypical protein kinase C (aPKC) and Lethal giant larvae (Lgl) regulate apical-basal polarity in Drosophila and mammalian epithelia. At the apical domain, aPKC phosphorylates and displaces Lgl that, in turn, maintains aPKC inactive at the basolateral region. The mutual exclusion of these two proteins seems to be crucial for the correct epithelial structure and function. Here we show that a cortical aPKC loading induces Lgl cytoplasmic release and massive overgrowth in Drosophila imaginal epithelia, whereas a cytoplasmic expression does not alter proliferation and epithelial overall structure. As two aPKC isoforms (iota and zeta) exist in humans and we previously showed that Drosophila Lgl i…

Survivin’s Dual Role: An Export’s View

2007

Survivin is proposed to function as a mitotic regulator and an apoptosis inhibitor during development and pathogenesis. As such, survivin has aroused keen interest in disparate areas of basic and translational research. Survivin acts as a subunit of the chromosomal passenger complex (CPC), composed of the mitotic kinase Aurora-B, Borealin and INCENP, and is essential for proper chromosome segregation and cytokinesis. Our recent findings indicate that the nuclear export receptor Crm1 is critically involved in tethering the CPC to the centromere by interacting with a leucine-rich nuclear export signal (NES), evolutionary conserved in all mammalian survivin proteins. In addition, the survivin/…