278 research outputs found
The Isolation by Self Gradients of Percoll of Plasma Membrane Enriched Fractions from Bovine Retinal Pigment Epithelium
No full textSelection at the wobble position of codons read by the same tRNA in Saccharomyces cerevisiae
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Retinol Uptake by Isolated Retinol Pigment Epithelium Plasma Membranes
No full textThe uptake of retinol has been investigated by incubating suspensions of isolated bovine retinal pigment epithelium plasma membranes in the presence of [3H]retinol-retinol-binding protein complex. After SDS gel electrophoresis of the labelled membranes, [3H]retinol is found to be associated with a protein band of molecular weight 16000. The binding process is saturable, specific and shows a linear dependence on the membrane concentration in the incubation mixture. A dissociation constant of the order of 10-9 has been calculated for the retinol-receptor interaction. These observations confirm previous data obtained with isolated pigment epithelium cells and suggest the existence of an intermediate step, at the membrane level, in the transfer of retinol from its plasma carrier to the cell cytoplasm. © 1981 Academic Press Inc. (London) Ltd
Membrane transporters and protein traffic networks differentially affecting metal tolerance: a genomic phenotyping study in yeast
No full textBACKGROUND:
The cellular mechanisms that underlie metal toxicity and detoxification are rather variegated and incompletely understood. Genomic phenotyping was used to assess the roles played by all nonessential Saccharomyces cerevisiae proteins in modulating cell viability after exposure to cadmium, nickel, and other metals.
RESULTS:
A number of novel genes and pathways that affect multimetal as well as metal-specific tolerance were discovered. Although the vacuole emerged as a major hot spot for metal detoxification, we also identified a number of pathways that play a more general, less direct role in promoting cell survival under stress conditions (for example, mRNA decay, nucleocytoplasmic transport, and iron acquisition) as well as proteins that are more proximally related to metal damage prevention or repair. Most prominent among the latter are various nutrient transporters previously not associated with metal toxicity. A strikingly differential effect was observed for a large set of deletions, the majority of which centered on the ESCRT (endosomal sorting complexes required for transport) and retromer complexes, which - by affecting transporter downregulation and intracellular protein traffic - cause cadmium sensitivity but nickel resistance.
CONCLUSION:
The data show that a previously underestimated variety of pathways are involved in cadmium and nickel tolerance in eukaryotic cells. As revealed by comparison with five additional metals, there is a good correlation between the chemical properties and the cellular toxicity signatures of various metals. However, many conserved pathways centered on membrane transporters and protein traffic affect cell viability with a surprisingly high degree of metal specificity
Purification of Human Plasma Retinol-Binding Protein by Hydrophobic Interaction Chromatography
No full textEnzyme reactivity in the crystal: Spectrphotometric studies of ligand binding and catalysis by chymotripsin
No full textRetinoic Acid Synthesis from Holo-Cellular Retinol Binding Protein in the Somatic Cells of Rat Testis.
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