A novel acidotropic pH indicator and its potential application in labeling acidic organelles of live cells.
AuthorsDiwu Z, Chen CS, Zhang C, Klaubert DH, Haugland RP
JournalChem Biol
PubMed ID10381401
'BACKGROUND: Ratio imaging has received intensive attention in the past few decades. The growing potential of ratio imaging is significantly limited, however, by the lack of appropriate fluorescent probes, for acidic organelles in particular. The classic fluorescent dyes (such as fluoresceins, rhodamines and coumarins) are not suitable for studying acidic ... More
Fluorescence lifetime characterization of novel low-pH probes.
AuthorsLin HJ, Herman P, Kang JS, Lakowicz JR
JournalAnal Biochem
PubMed ID11444806
'The structures and functions of the cellular acidic compartments are strongly dependent on the pH gradients across vesicular membranes. Measurement and imaging of the vesicular pH require fluorophores with appropriate pK(a) values. In this report, we characterized the pH-dependent lifetime responses of a family of acidotropic probes, LysoSensors, to evaluate ... More
Glucose acutely decreases pH of secretory granules in mouse pancreatic islets. Mechanisms and influence on insulin secretion.
AuthorsStiernet P, Guiot Y, Gilon P, Henquin JC
JournalJ Biol Chem
PubMed ID16760469
'Glucose-induced insulin secretion requires a rise in beta-cell cytosolic Ca2+ ([Ca2+]c) that triggers exocytosis and a mechanistically unexplained amplification of the action of [Ca2+]c. Insulin granules are kept acidic by luminal pumping of protons with simultaneous Cl- uptake to maintain electroneutrality. Experiments using patched, dialyzed beta-cells prompted the suggestion that ... More
Elevated lysosomal pH in neuronal ceroid lipofuscinoses (NCLs).
AuthorsHolopainen JM, Saarikoski J, Kinnunen PK, Järvelä I
JournalEur J Biochem
PubMed ID11722572
'We report here the intracellular (pHi) and lysosomal pH in fibroblasts of six forms of neuronal ceroid lipofuscinoses (NCLs). Acid extrusion rate and pH(i) values were measured by the membrane-permeant acetoxymethyl ester of the indicator dye, 2'',7''-bis(carboxyethyl)-5-(and-6)-carboxy-fluorescein (BCECF) and lysosomal pH by a spectrofluorometric assay utilizing a novel acidotropic probe, ... More
Divalent cations regulate acidity within the lumen and tubulovesicle compartment of gastric parietal cells.
AuthorsGerbino A, Hofer AM, McKay B, Lau BW, Soybel DI
JournalGastroenterology
PubMed ID14699499
'Background & Aims: Until recently, it has not been possible to evaluate factors that regulate the acidity of the microenvironment within the tubulovesicles and luminal (TV/L) spaces of the gastric gland. The goal of this study was to develop a method for monitoring the mechanisms that regulate acidity in the ... More
Platelet-activating factor stimulates cytoplasmic alkalinization and granule acidification in human eosinophils.
AuthorsBankers-Fulbright JL, Kephart GM, Bartemes KR, Kita H, O'Grady SM
JournalJ Cell Sci
PubMed ID15507482
'The effects of platelet-activating factor (PAF) and IL-5 on intracellular pH were investigated in human eosinophils. Purified peripheral blood eosinophils were loaded with the ratiometric fluorescent pH indicator BCECF-AM ester. Stimulation of eosinophils with PAF produced time-dependent alkalinization of the cytoplasm from an initial pH of 7.1+/-0.04 to 7.5+/-0.05. A ... More
Vesicular anthracycline accumulation in doxorubicin-selected U-937 cells: participation of lysosomes.
AuthorsHurwitz SJ, Terashima M, Mizunuma N, Slapak CA
JournalBlood
PubMed ID9160680
'The U-A10 cell line, a doxorubicin-selected variant of human U-937 myeloid leukemia cells, exhibits a redistribution of anthracyclines into a expanded vesicular compartment. The acidic nature of this compartment was confirmed by vital staining with a pH sensitive dye, LysoSensor yellow/blue DND-160. Identification of the vesicular compartment was performed by ... More
Replication of Cryptococcus neoformans in macrophages is accompanied by phagosomal permeabilization and accumulation of vesicles containing polysaccharide in the cytoplasm.
AuthorsTucker SC, Casadevall A
JournalProc Natl Acad Sci U S A
PubMed ID11880650
'Cryptococcus neoformans (CN), an encapsulated, ubiquitous environmental yeast, is pathogenic for humans, primarily those with compromised immune function. CN is believed to be a facultative intracellular pathogen. Time-lapsed video microscopy revealed that yeast began to replicate and divide 2 hours after ingestion by J774.16 macrophage cells, with the average cell ... More
Evaluation of disulfide reduction during receptor-mediated endocytosis by using FRET imaging.
AuthorsYang J, Chen H, Vlahov IR, Cheng JX, Low PS
JournalProc Natl Acad Sci U S A
PubMed ID16950881
'Despite functional evidence for disulfide bond-reducing activity in endosomal compartments, the mechanistic details pertaining to such process (e.g., kinetics and sites of disulfide reduction) remain largely controversial. To address these questions directly, we have synthesized a previously uncharacterized fluorescent folate conjugate, folate-(BODIPY FL)-SS-rhodamine (folate-FRET), that changes fluorescence from red to ... More
Fluorescent indicators for intracellular pH.
AuthorsHan J, Burgess K,
JournalChem Rev
PubMed ID19831417
This review is about intracellular pH sensors, includingsmall fluorescent organic molecules, nanoparticles, andfluorescent proteins, e.g., GFP. It focuses on their preparations, photophysical properties, and advantages/disadvantagesfor intracellular pH measurements. The discussion is limitedto fluorescent indicators that have been applied to measureintracellular pH values since 1980. ... More
Using LysoSensor Yellow/Blue DND-160 to sense acidic pH under high hydrostatic pressures.
AuthorsDePedro HM, Urayama P,
JournalAnal Biochem
PubMed ID18976626
LysoSensor Yellow/Blue DND-160, a dual-wavelength fluorophore commonly used for sensing pH in acidic organelles, possesses solvatochromic behavior believed to originate from an intramolecular charge transfer (ICT). Given this, we investigated whether DND-160 can be used for acidic pH sensing under hydrostatic pressures up to 510 atm, a range suitable for ... More
Whole-genome expression profiling of the marine diatom Thalassiosira pseudonana identifies genes involved in silicon bioprocesses.
AuthorsMock T, Samanta MP, Iverson V, Berthiaume C, Robison M, Holtermann K, Durkin C, Bondurant SS, Richmond K, Rodesch M, Kallas T, Huttlin EL, Cerrina F, Sussman MR, Armbrust EV,
JournalProc Natl Acad Sci U S A
PubMed ID18212125
Formation of complex inorganic structures is widespread in nature. Diatoms create intricately patterned cell walls of inorganic silicon that are a biomimetic model for design and generation of three-dimensional silica nanostructures. To date, only relatively simple silica structures can be generated in vitro through manipulation of known diatom phosphoproteins (silaffins) ... More
Dynamics of silica cell wall morphogenesis in the diatom Cyclotella cryptica: substructure formation and the role of microfilaments.
AuthorsTesson B, Hildebrand M,
JournalJ Struct Biol
PubMed ID19729066
Diatoms are unicellular algae that make cell walls out of silica with highly ornate features on the nano- to microscale. The complexity and variety of diatom cell wall structures exceeds those possible with synthetic materials chemistry approaches. Understanding the design and assembly processes involved in diatom silicification should provide insight ... More
Barley aleurone cells contain two types of vacuoles. Characterization Of lytic organelles by use of fluorescent probes
AuthorsSwanson SJ, Bethke PC, Jones RL
JournalPlant Cell
PubMed ID9596630
Light microscopy was used to study the structure and function of vacuoles in living protoplasts of barley (Hordeum vulgare cv Himalaya) aleurone. Light microscopy showed that aleurone protoplasts contain two distinct types of vacuole: the protein storage vacuole and a lysosome-like organelle, which we have called the secondary vacuole. Fluorescence ... More
A novel fluorescent silica tracer for biological silicification studies.
AuthorsShimizu K, Del Amo Y, Brzezinski MA, Stucky GD, Morse DE
JournalChem Biol
PubMed ID11731296
BACKGROUND: Biological silica production has drawn intense attention and several molecules involved in biosilicification have been identified. Cellular mechanisms, however, remain unknown mainly due to the lack of probes required for obtaining information on live specimens. RESULTS: The fluorescence spectra of the compound 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole (PDMPO) are affected by the presence ... More
Silica transport in the demosponge Suberites domuncula: fluorescence emission analysis using the PDMPO probe and cloning of a potential transporter.
AuthorsSchröder HC, Perovic-Ottstadt S, Rothenberger M, Wiens M, Schwertner H, Batel R, Korzhev M, Müller IM, Müller WE
JournalBiochem J
PubMed ID15128286
Silicon is, besides oxygen, the most abundant element on earth. Only two taxa use this element as a major constituent of their skeleton, namely sponges (phylum Porifera) and unicellular diatoms. Results from combined cytobiological and molecularbiological techniques suggest that, in the demosponge Suberites domuncula, silicic acid is taken up by ... More
Analysis of Thalassiosira pseudonana silicon transporters indicates distinct regulatory levels and transport activity through the cell cycle.
AuthorsThamatrakoln K, Hildebrand M
JournalEukaryot Cell
PubMed ID17172435
An analysis of the expression and activity of silicon transporters (SITs) was done on synchronously growing cultures of the diatom Thalassiosira pseudonana to provide insight into the role these proteins play in cellular silicon metabolism during the cell cycle. The first SIT-specific polyclonal peptide antibody was generated and used in ... More
Simultaneous measurement and imaging of intracellular Ca(2+) and H(+) transport in isolated rabbit gastric glands.
AuthorsPérez JF, Ruiz MC, Michelangeli F
JournalJ Physiol
PubMed ID11744751
1. Activation of H(+) secretion in the intracellular canaliculi of parietal cells occurs on an unknown time scale with ill-defined kinetics for the coupling of H(+) secretion and the elevation of intracellular calcium ([Ca(2+)](i)) stimulated by secretagogues. 2. We developed a method to determine H(+) secretion in isolated rabbit gastric ... More
CD44 interaction with Na+-H+ exchanger (NHE1) creates acidic microenvironments leading to hyaluronidase-2 and cathepsin B activation and breast tumor cell invasion.
AuthorsBourguignon LY, Singleton PA, Diedrich F, Stern R, Gilad E
JournalJ Biol Chem
PubMed ID15090545
We have explored CD44 (a hyaluronan (HA) receptor) interaction with a Na(+)-H(+) exchanger (NHE1) and hyaluronidase-2 (Hyal-2) during HA-induced cellular signaling in human breast tumor cells (MDA-MB-231 cell line). Immunological analyses demonstrate that CD44s (standard form) and two signaling molecules (NHE1 and Hyal-2) are closely associated in a complex in ... More
Fluorescence lifetime-resolved pH imaging of living cells.
AuthorsLin HJ, Herman P, Lakowicz JR
JournalCytometry A
PubMed ID12655651
BACKGROUND: The regulation and maintenance of intracellular pH are critical to diverse metabolic functions of the living cells. Fluorescence time-resolved techniques and instrumentations have advanced rapidly and enabled the imaging of intracellular pH based on the fluorescence lifetimes. METHODS: The frequency-domain fluorescence lifetime imaging microscopy (FLIM) and fluorophores displaying appropriate ... More
Reactivity of apolipoprotein E4 and amyloid beta peptide: lysosomal stability and neurodegeneration.
AuthorsJi ZS, Müllendorff K, Cheng IH, Miranda RD, Huang Y, Mahley RW
JournalJ Biol Chem
PubMed ID16298992
We previously demonstrated that apolipoprotein E4 (apoE4) potentiates lysosomal leakage and apoptosis induced by amyloid beta (Abeta) peptide in cultured Neuro-2a cells and hypothesized that the low pH of lysosomes accentuates the conversion of apoE4 to a molten globule, inducing reactive intermediates capable of destabilizing cellular membranes. Here we report ... More
The lipofuscin fluorophore A2E perturbs cholesterol metabolism in retinal pigment epithelial cells.
AuthorsLakkaraju A, Finnemann SC, Rodriguez-Boulan E
JournalProc Natl Acad Sci U S A
PubMed ID17578916
Proteins involved in cholesterol trafficking are known to contribute to the pathogenesis of atherosclerosis and Alzheimer's disease. Allelic variants in the cholesterol transporters apolipoprotein E and ATP-binding cassette protein A1 (ABCA1) have recently been associated with susceptibility to age-related macular degeneration (AMD). Histopathological analyses of eyes with AMD demonstrate the ... More
Regulated proteolysis by cortical granule serine protease 1 at fertilization.
AuthorsHaley SA, Wessel GM
JournalMol Biol Cell
PubMed ID14978210
Cortical granules are specialized organelles whose contents interact with the extracellular matrix of the fertilized egg to form the block to polyspermy. In sea urchins, the granule contents form a fertilization envelope (FE), and this construction is critically dependent upon protease activity. An autocatalytic serine protease, cortical granule serine protease ... More
Limitation of TCA Cycle Intermediates Represents an Oxygen-Independent Nutritional Antibacterial Effector Mechanism of Macrophages.
AuthorsHayek I, Fischer F, Schulze-Luehrmann J, Dettmer K, Sobotta K, Schatz V, Kohl L, Boden K, Lang R, Oefner PJ, Wirtz S, Jantsch J, Lührmann A
JournalCell Rep
PubMed ID30917307
'In hypoxic and inflamed tissues, oxygen (O'
Age-related endolysosome dysfunction in the rat urothelium.
AuthorsTruschel ST, Clayton DR, Beckel JM, Yabes JG, Yao Y, Wolf-Johnston A, Birder LA, Apodaca G
JournalPLoS One
PubMed ID29883476
'Lysosomal dysfunction is associated with a number of age-related pathologies that affect all organ systems. While much research has focused on neurodegenerative diseases and aging-induced changes in neurons, much less is known about the impact that aging has on lower urinary tract function. Our studies explored age-dependent changes in the ... More
Contact inhibition controls cell survival and proliferation via YAP/TAZ-autophagy axis.
AuthorsPavel M, Renna M, Park SJ, Menzies FM, Ricketts T, Füllgrabe J, Ashkenazi A, Frake RA, Lombarte AC, Bento CF, Franze K, Rubinsztein DC
JournalNat Commun
PubMed ID30054475
'Contact inhibition enables noncancerous cells to cease proliferation and growth when they contact each other. This characteristic is lost when cells undergo malignant transformation, leading to uncontrolled proliferation and solid tumor formation. Here we report that autophagy is compromised in contact-inhibited cells in 2D or 3D-soft extracellular matrix cultures. In ... More
Type I interferon remodels lysosome function and modifies intestinal epithelial defense.
Authors
JournalProc Natl Acad Sci U S A
PubMed ID33172989
Loss of PIKfyve drives the spongiform degeneration in prion diseases.
Authors
JournalEMBO Mol Med
PubMed ID34291577
IRGM1 links mitochondrial quality control to autoimmunity.
Authors
JournalNat Immunol
PubMed ID33510463
Eicosapentaenoic acid attenuates renal lipotoxicity by restoring autophagic flux.
Authors
JournalAutophagy
PubMed ID32546086
Activation of lysosomal function in the course of autophagy via mTORC1 suppression and autophagosome-lysosome fusion.
Authors
JournalCell Res
PubMed ID23337583
Spermine synthase deficiency causes lysosomal dysfunction and oxidative stress in models of Snyder-Robinson syndrome.
Authors
JournalNat Commun
PubMed ID29097652
NDST3 deacetylates α-tubulin and suppresses V-ATPase assembly and lysosomal acidification.
Authors
JournalEMBO J
PubMed ID34435379
A growth-factor-activated lysosomal K+ channel regulates Parkinson's pathology.
The interferon-inducible isoform of NCOA7 inhibits endosome-mediated viral entry.
AuthorsDoyle T, Moncorgé O, Bonaventure B, Pollpeter D, Lussignol M, Tauziet M, Apolonia L, Catanese MT, Goujon C, Malim MH
JournalNat Microbiol
PubMed ID30478388
Interferons (IFNs) mediate cellular defence against viral pathogens by upregulation of IFN-stimulated genes whose products interact with viral components or alter cellular physiology to suppress viral replication ... More
CX-4945 Induces Methuosis in Cholangiocarcinoma Cell Lines by a CK2-Independent Mechanism.
AuthorsLertsuwan J, Lertsuwan K, Sawasdichai A, Tasnawijitwong N, Lee KY, Kitchen P, Afford S, Gaston K, Jayaraman PS, Satayavivad J
JournalCancers (Basel)
PubMed ID30142881
Cholangiocarcinoma is a disease with a poor prognosis and increasing incidence and hence there is a pressing unmet clinical need for new adjuvant treatments. Protein kinase CK2 (previously casein kinase II) is a ubiquitously expressed protein kinase that is up-regulated in multiple cancer cell types. The inhibition of CK2 activity ... More
Pharmacological enhancement of TFEB-mediated autophagy alleviated neuronal death in oxidative stress-induced Parkinson's disease models.
AuthorsZhuang XX, Wang SF, Tan Y, Song JX, Zhu Z, Wang ZY, Wu MY, Cai CZ, Huang ZJ, Tan JQ, Su HX, Li M, Lu JH
JournalCell Death Dis
PubMed ID32071296
Autophagy, a conserved cellular degradation and recycling process, can be enhanced by nutrient depletion, oxidative stress or other harmful conditions to maintain cell survival. 6-Hydroxydopamine/ascorbic acid (6-OHDA/AA) is commonly used to induce experimental Parkinson's disease (PD) lesions by causing oxidative damage to dopaminergic neurons. Activation of autophagy has been observed ... More