Morphological localisation of sulfonylurea receptor 1 in endocrine cells of human, mouse and rat pancreas.
AuthorsGuiot Y, Stevens M, Marhfour I, Stiernet P, Mikhailov M, Ashcroft SJ, Rahier J, Henquin JC, Sempoux C,
JournalDiabetologia
PubMed ID17593344
'AIMS/HYPOTHESIS: Sulfonylurea receptor 1 (SUR1) is the regulatory subunit of ATP-sensitive K channels in beta cells. Morphological methods (immunohistochemistry and sulfonylurea binding) were used to establish the cellular and subcellular location of SUR1 in human and rodent islets. RESULTS: In the human, mouse and rat pancreas, all endocrine cells of ... More
Live intracellular super-resolution imaging using site-specific stains.
AuthorsCarlini L, Manley S,
Journal
PubMed ID24079385
'Point localization super-resolution imaging (SR) requires dyes that can cycle between fluorescent and dark states, in order for their molecular positions to be localized and create a reconstructed image. Dyes should also densely decorate biological features of interest to fully reveal structures being imaged. We tested site-specific dyes in several ... More
Suicidal membrane repair regulates phosphatidylserine externalization during apoptosis.
One of the hallmarks of apoptosis is the redistribution of phosphatidylserine (PS) from the inner-to-outer plasma membrane (PM) leaflet, where it functions as a ligand for phagocyte recognition and the suppression of inflammatory responses. The mechanism by which apoptotic cells externalize PS has been assumed to involve ... More
Mitochondrial autophagy is an HIF-1-dependent adaptive metabolic response to hypoxia.
AuthorsZhang H, Bosch-Marce M, Shimoda LA, Tan YS, Baek JH, Wesley JB, Gonzalez FJ, Semenza GL,
JournalJ Biol Chem
PubMed ID18281291
Autophagy is a process by which cytoplasmic organelles can be catabolized either to remove defective structures or as a means of providing macromolecules for energy generation under conditions of nutrient starvation. In this study we demonstrate that mitochondrial autophagy is induced by hypoxia, that this process requires the hypoxia-dependent factor-1-dependent ... More
Translocation of a phycoerythrin alpha subunit across five biological membranes.
AuthorsGould SB, Fan E, Hempel F, Maier UG, Klösgen RB,
JournalJ Biol Chem
PubMed ID17702756
Cryptophytes, unicellular algae, evolved by secondary endosymbiosis and contain plastids surrounded by four membranes. In contrast to cyanobacteria and red algae, their phycobiliproteins do not assemble into phycobilisomes and are located within the thylakoid lumen instead of the stroma. We identified two gene families encoding phycoerythrin alpha and light-harvesting complex ... More
Determining the distribution of probes between different subcellular locations through automated unmixing of subcellular patterns.
Many proteins or other biological macromolecules are localized to more than one subcellular structure. The fraction of a protein in different cellular compartments is often measured by colocalization with organelle-specific fluorescent markers, requiring availability of fluorescent probes for each compartment and acquisition of images for each in conjunction with the ... More
The utilization of pathogen-like cellular trafficking by single chain block copolymer.
Amphiphilic triblock copolymer, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), Pluronic P85, is unexpectedly shown to utilize sophisticated cellular trafficking mechanisms and enter brain microvessel endothelial cells and primary neurons that are poorly penetrable. Though caveolae serve as a primary entry site for the copolymer single chains, in cells devoid of caveolae, the ... More
Bioinformatic and image analyses of the cellular localization of the apoptotic proteins endonuclease G, AIF, and AMID during apoptosis in human cells.
AuthorsVarecha M, Amrichová J, Zimmermann M, Ulman V, Lukásová E, Kozubek M
JournalApoptosis
PubMed ID17347867
We studied the cellular localization of the apoptotic proteins endonuclease G, AIF, and AMID in silico using three prediction tools and in living cells using both single-cell colocalization image analysis and nuclear translocation analysis. We confirmed the mitochondrial localization of endonuclease G and AIF by prediction analysis and by single-cell ... More
AuthorsSimard JM, Chen M, Tarasov KV, Bhatta S, Ivanova S, Melnitchenko L, Tsymbalyuk N, West GA, Gerzanich V
JournalNat Med
PubMed ID16550187
Pathological conditions in the central nervous system, including stroke and trauma, are often exacerbated by cerebral edema. We recently identified a nonselective cation channel, the NC(Ca-ATP) channel, in ischemic astrocytes that is regulated by sulfonylurea receptor 1 (SUR1), is opened by depletion of ATP and, when opened, causes cytotoxic edema. ... More
Identification and properties of a novel intracellular (mitochondrial) ATP-sensitive potassium channel in brain.
AuthorsBajgar R, Seetharaman S, Kowaltowski AJ, Garlid KD, Paucek P
JournalJ Biol Chem
PubMed ID11441006
Protection of heart against ischemia-reperfusion injury by ischemic preconditioning and K(ATP) channel openers is known to involve the mitochondrial ATP-sensitive K(+) channel (mitoK(ATP)). Brain is also protected by ischemic preconditioning and K(ATP) channel openers, and it has been suggested that mitoK(ATP) may also play a key role in brain protection. ... More
Oxidant generation with K(+)-induced depolarization in the isolated perfused lung.
Authorsal-Mehdi AB, Shuman H, Fisher AB
JournalFree Radic Biol Med
PubMed ID9165296
This study evaluated whether cell membrane depolarization can induce oxidant generation in the isolated perfused rat lung as has been demonstrated with bovine pulmonary artery endothelial cells. Depolarization was produced by perfusing the lungs with high [K+] or with glyburide and was evaluated with bis-oxonol lung surface fluorometry. Lung surface ... More
Functional and trafficking defects in ATP binding cassette A3 mutants associated with respiratory distress syndrome.
AuthorsCheong N, Madesh M, Gonzales LW, Zhao M, Yu K, Ballard PL, Shuman H
JournalJ Biol Chem
PubMed ID16415354
Members of the ATP binding cassette (ABC) protein superfamily actively transport a wide range of substrates across cell and intracellular membranes. Mutations in ABCA3, a member of the ABCA subfamily with unknown function, lead to fatal respiratory distress syndrome (RDS) in the newborn. Using cultured human lung cells, we found ... More
Different effects of tolbutamide and diazoxide in alpha, beta-, and delta-cells within intact islets of Langerhans.
AuthorsQuesada I, Nadal A, Soria B
JournalDiabetes
PubMed ID10580428
Interaction between the different types of cells within the islet of Langerhans is vital for adequate control of insulin release. Once insulin secretion becomes defective, as in type 2 diabetes, the most useful drugs to increase insulin release are sulfonylureas. It is well-known that sulfonylureas block K(ATP) channels, which results ... More
Expression of sulphonylurea receptors in bovine monocytes from animals with a different metabolic rate.
AuthorsLöhrke B, Derno M, Krüger B, Viergutz T, Matthes H, Jentsch W
JournalPflugers Arch
PubMed ID9306003
The aim of this study was to investigate the relationship between expression of sulphonylurea receptors (SUR) and metabolic rate (MR). SUR on monocytes and cells from muscle tissue were detected using fluorescent glibenclamide and flow cytometry. Transmembrane potential differences were detected by oxonol dye fluorescence measurements. A bovine model was ... More
The insulin secretory granule is the major site of K(ATP) channels of the endocrine pancreas.
AuthorsGeng X, Li L, Watkins S, Robbins PD, Drain P
JournalDiabetes
PubMed ID12606519
With ATP sites on K(ir)6.2 that inhibit activity and ADP sites on SUR1 that antagonize the inhibition, ATP-sensitive potassium channels (K(ATP) channels) are designed as exquisite sensors of adenine nucleotide levels that signal changes in glucose metabolism. If pancreatic K(ATP) channels localize to the insulin secretory granule, they would be ... More
AuthorsLacza Z, Snipes JA, Miller AW, Szabó C, Grover G, Busija DW
JournalJ Mol Cell Cardiol
PubMed ID14596790
Recent observations challenged the functional importance or even the existence of mitochondrial ATP-dependent K+ (mitoK(ATP)) channels. In the present study, we determined the presence of K(ATP)-channel subunits in mouse heart mitochondria, and investigated whether known openers or blockers of the channel can alter mitochondrial membrane potential. Investigation of the channel ... More
Fluorescence microscopy studies with a fluorescent glibenclamide derivative, a high-affinity blocker of pancreatic beta-cell ATP-sensitive K+ currents.
AuthorsZünkler BJ, Wos-Maganga M, Panten U
JournalBiochem Pharmacol
PubMed ID15041461
Hypoglycemic sulfonylureas (e.g. tolbutamide, glibenclamide) exert their stimulatory effects on pancreatic beta-cells by closure of ATP-sensitive K(+) (K(ATP)) channels. Pancreatic K(ATP) channels are composed of two subunits, a pore-forming inwardly rectifying K(+) channel (Kir6.2) subunit and a regulatory subunit (the sulfonylurea receptor of subtype 1 (SUR1)) in a (SUR1/Kir6.2)(4) stoichiometry. ... More
An ATP-sensitive K(+) conductance in dissociated neurones from adult rat intracardiac ganglia.
AuthorsHogg RC, Adams DJ
JournalJ Physiol
PubMed ID11483702
1. An ATP-sensitive K(+) (K(ATP)) conductance has been identified using the perforated patch recording configuration in a population (52%) of dissociated neurones from adult rat intracardiac ganglia. The presence of the sulphonylurea receptor in approximately half of the intracardiac neurones was confirmed by labelling with fluorescent glibenclamide-BODIPY. 2. Under current ... More
Late Endosomes Act as mRNA Translation Platforms and Sustain Mitochondria in Axons.