scholarly journals Mitochondrial membrane potential regulates PINK1 import and proteolytic destabilization by PARL

2010 ◽  
Vol 191 (5) ◽  
pp. 933-942 ◽  
Author(s):  
Seok Min Jin ◽  
Michael Lazarou ◽  
Chunxin Wang ◽  
Lesley A. Kane ◽  
Derek P. Narendra ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Dopaminergic Neurons ◽  
Mammalian Cells ◽  
Mitochondrial Membrane ◽  
Mitochondrial Membranes ◽  
Rhomboid Protease ◽  
Mitochondrial Inner Membrane ◽  
Flight Muscles ◽  
And Function

PINK1 is a mitochondrial kinase mutated in some familial cases of Parkinson’s disease. It has been found to work in the same pathway as the E3 ligase Parkin in the maintenance of flight muscles and dopaminergic neurons in Drosophila melanogaster and to recruit cytosolic Parkin to mitochondria to mediate mitophagy in mammalian cells. Although PINK1 has a predicted mitochondrial import sequence, its cellular and submitochondrial localization remains unclear in part because it is rapidly degraded. In this study, we report that the mitochondrial inner membrane rhomboid protease presenilin-associated rhomboid-like protein (PARL) mediates cleavage of PINK1 dependent on mitochondrial membrane potential. In the absence of PARL, the constitutive degradation of PINK1 is inhibited, stabilizing a 60-kD form inside mitochondria. When mitochondrial membrane potential is dissipated, PINK1 accumulates as a 63-kD full-length form on the outer mitochondrial membrane, where it can recruit Parkin to impaired mitochondria. Thus, differential localization to the inner and outer mitochondrial membranes appears to regulate PINK1 stability and function.

scholarly journals Review of T-2307, an Investigational Agent That Causes Collapse of Fungal Mitochondrial Membrane Potential

2021 ◽  
Vol 7 (2) ◽  
pp. 130
Author(s):  
Nathan P. Wiederhold
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Candida Species ◽  
Mammalian Cells ◽  
Mitochondrial Membrane ◽  
Fungal Infections ◽  
Published Data ◽  
Candida Auris

Invasive infections caused by Candida that are resistant to clinically available antifungals are of increasing concern. Increasing rates of fluconazole resistance in non-albicans Candida species have been documented in multiple countries on several continents. This situation has been further exacerbated over the last several years by Candida auris, as isolates of this emerging pathogen that are often resistant to multiple antifungals. T-2307 is an aromatic diamidine currently in development for the treatment of invasive fungal infections. This agent has been shown to selectively cause the collapse of the mitochondrial membrane potential in yeasts when compared to mammalian cells. In vitro activity has been demonstrated against Candida species, including C. albicans, C. glabrata, and C. auris strains, which are resistant to azole and echinocandin antifungals. Activity has also been reported against Cryptococcus species, and this has translated into in vivo efficacy in experimental models of invasive candidiasis and cryptococcosis. However, little is known regarding the clinical efficacy and safety of this agent, as published data from studies involving humans are not currently available.

scholarly journals Analysis of mitochondrial morphology and function with novel fixable fluorescent stains.

1996 ◽  
Vol 44 (12) ◽  
pp. 1363-1372 ◽  
Author(s):  
M Poot ◽  
Y Z Zhang ◽  
J A Krämer ◽  
K S Wells ◽  
L J Jones ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Epifluorescence Microscopy ◽  
Mitochondrial Morphology ◽  
Microtubule Network ◽  
Multiple Features ◽  
Permeabilized Cells ◽  
Dye Staining ◽  
And Function

Investigation of mitochondrial morphology and function has been hampered because photostable, mitochondrion-specific stains that are retained in fixed, permeabilized cells have not been available. We found that in live cell preparations, the CMXRos and H2-CMXRos dyes were more photostable than rhodamine 123. In addition, fluorescence and morphology of mitochondria stained with the CMXRos and CMXRos-H2 dyes were preserved even after formaldehyde fixation and acetone permeabilization. Using epifluorescence microscopy, we showed that CMXRos and H2-CMXRos dye fluorescence fully co-localized with antibodies to subunit I of cytochrome c oxidase, indicating that the dyes specifically stain mitochondria. Confocal microscopy of these mitochondria yielded colored banding patterns, suggesting that these dyes and the mitochondrial enzyme localize to different suborganellar regions. Therefore, these stains provide powerful tools for detailed analysis of mitochondrial fine structure. We also used poisons that decrease mitochondrial membrane potential and an inhibitor of respiration complex II to show by flow cytometry that the fluorescence intensity of CMXRos and H2-CMXRos dye staining responds to changes in mitochondrial membrane potential and function. Hence, CMXRos has the potential to monitor changes in mitochondrial function. In addition, CMXRos staining was used in conjunction with spectrally distinct fluorescent probes for the cell nucleus and the microtubule network to concomitantly evaluate multiple features of cell morphology.

Visualization of mitochondrial membrane potential in mammalian cells

2020 ◽  
pp. 221-245
Author(s):  
Noemí Esteras ◽  
Merel J.W. Adjobo-Hermans ◽  
Andrey Y. Abramov ◽  
Werner J.H. Koopman
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mammalian Cells ◽  
Mitochondrial Membrane

Glutamine protects mitochondrial structure and function in oxygen toxicity

2001 ◽  
Vol 280 (4) ◽  
pp. L779-L791 ◽  
Author(s):  
Shama Ahmad ◽  
Carl W. White ◽  
Ling-Yi Chang ◽  
Barbara K. Schneider ◽  
Corrie B. Allen
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Tricarboxylic Acid Cycle ◽  
A549 Cells ◽  
Oxygen Toxicity ◽  
Cycle Enzyme ◽  
Glutamine Deprivation ◽  
And Function ◽  
Dose Dependent Increase

Glutamine is an important mitochondrial substrate implicated in the protection of cells from oxidant injury, but the mechanisms of its action are incompletely understood. Human pulmonary epithelial-like (A549) cells were exposed to 95% O2 for 4 days in the absence and presence of glutamine. Cell proliferation in normoxia was dependent on glutamine, and glutamine deprivation markedly accelerated cell death in hyperoxia. Glutamine significantly increased cellular ATP levels in normoxia and prevented the loss of ATP in hyperoxia seen in glutamine-deprived cells. Mitochondrial membrane potential as assessed by flow cytometry with chloromethyltetramethylrosamine was increased by glutamine in hyperoxia-exposed A549 cells, and a glutamine dose-dependent increase in mitochondrial membrane potential was detected. Glutamine-supplemented, hyperoxia-exposed cells had a higher O2 consumption rate and GSH content. Electron and fluorescence microscopy revealed that, in hyperoxia, glutamine protected cellular structures, especially mitochondria, from damage. In hyperoxia, activity of the tricarboxylic acid cycle enzyme α-ketoglutarate dehydrogenase was partially protected by its indirect substrate, glutamine, indicating a mechanism of mitochondrial protection.

scholarly journals Development of a High Throughput Screening Assay for Mitochondrial Membrane Potential in Living Cells

2002 ◽  
Vol 7 (4) ◽  
pp. 383-389 ◽  
Author(s):  
Shu-Gui Huang
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
High Throughput ◽  
High Throughput Screening ◽  
Mitochondrial Membrane ◽  
Living Cells ◽  
Screening Assay ◽  
Mitochondrial Inner Membrane ◽  
Obesity And Diabetes ◽  
High Throughput Screening Assay

The mitochondrion plays a pivotal role in energy metabolism in eukaryotic cells. The electrochemical potential across the mitochondrial inner membrane is regulated to cope with cellular energy needs and thus reflects the bioenergetic state of the cell. Traditional assays for mitochondrial membrane potential are not amenable to high-throughput drug screening. In this paper, I describe a high-throughput assay that measures the mitochondrial membrane potential of living cells in 96- or 384-well plates. Cells were first treated with test compounds and then with a fluorescent potentiometric probe, the cationic-lipophilic dye tetramethylrhodamine methyl ester (TMRM). The cells were then washed to remove free compounds and probe. The amount of TMRM retained in the mitochondria, which is proportional to the mitochondrial membrane potential, was measured on an LJL Analyst fluorescence reader. Under optimal conditions, the assay measured only the mitochondrial membrane potential. The chemical uncouplers carbonylcyanide m-chlorophenyl hydrazone and dinitrophenol decreased fluorescence intensity, with IC50 values (concentration at 50% inhibition) similar to those reported in the literature. A Z' factor of greater than 0.5 suggests that this cell-based assay can be adapted for high-throughput screening of chemical libraries. This assay may be used in screens for drugs to treat metabolic disorders such as obesity and diabetes, as well as cancer and neurodegenerative diseases.

scholarly journals Inducible proteolytic inactivation of OPA1 mediated by the OMA1 protease in mammalian cells

2009 ◽  
Vol 187 (7) ◽  
pp. 959-966 ◽  
Author(s):  
Brian Head ◽  
Lorena Griparic ◽  
Mandana Amiri ◽  
Shilpa Gandre-Babbe ◽  
Alexander M. van der Bliek
Keyword(s):  
Membrane Potential ◽  
Mammalian Cells ◽  
Small Interfering Rna ◽  
Mitochondrial Network ◽  
Membrane Fusion Protein ◽  
Zinc Metalloprotease ◽  
Mitochondrial Inner Membrane ◽  
Proteolytic Cascade ◽  
And Function ◽  
Interfering Rna

The mammalian mitochondrial inner membrane fusion protein OPA1 is controlled by complex patterns of alternative splicing and proteolysis. A subset of OPA1 isoforms is constitutively cleaved by YME1L. Other isoforms are not cleaved by YME1L, but they are cleaved when mitochondria lose membrane potential or adenosine triphosphate. In this study, we show that this inducible cleavage is mediated by a zinc metalloprotease called OMA1. We find that OMA1 small interfering RNA inhibits inducible cleavage, helps retain fusion competence, and slows the onset of apoptosis, showing that OMA1 controls OPA1 cleavage and function. We also find that OMA1 is normally cleaved from 60 to 40 kD by another as of yet unidentified protease. Loss of membrane potential causes 60-kD protein to accumulate, suggesting that OMA1 is attenuated by proteolytic degradation. We conclude that a proteolytic cascade controls OPA1. Inducible cleavage provides a mechanism for quality control because proteolytic inactivation of OPA1 promotes selective removal of defective mitochondrial fragments by preventing their fusion with the mitochondrial network.

scholarly journals Rhomboid Protease PARL Mediates the Mitochondrial Membrane Potential Loss-induced Cleavage of PGAM5

2012 ◽  
Vol 287 (41) ◽  
pp. 34635-34645 ◽  
Author(s):  
Shiori Sekine ◽  
Yusuke Kanamaru ◽  
Masato Koike ◽  
Ayako Nishihara ◽  
Masahiro Okada ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Rhomboid Protease ◽  
Potential Loss ◽  
Mitochondrial Membrane Potential Loss

scholarly journals PINK1 phosphorylates ubiquitin predominantly in astrocytes

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Sandeep K. Barodia ◽  
Laura J. McMeekin ◽  
Rose B. Creed ◽  
Elijah K. Quinones ◽  
Rita M. Cowell ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Dopaminergic Neurons ◽  
Mitochondrial Membrane ◽  
Oligodendrocyte Progenitor Cells ◽  
Primary Neurons ◽  
Loss Of Function ◽  
Critical Function ◽  
Rat Pups ◽  
Steady State Levels

AbstractLoss-of-function mutations in PINK1 are causally linked to recessively inherited Parkinson’s disease (PD), with marked loss of dopaminergic neurons in the substantia nigra that are required for normal movement. PINK1 is a nuclear-encoded mitochondrial-targeted kinase that phosphorylates a conserved serine at amino acid 65 (pS65) in ubiquitin as well as Parkin, another gene with loss-of-function mutations linked to recessive parkinsonism. The steady-state levels of PINK1 protein are very low, even in cells that express PINK1, because PINK1 is normally targeted for degradation after mitochondrial import by a process that is dependent upon mitochondrial membrane potential. Dissipation of the mitochondrial membrane potential with ionophores, such as CCCP and valinomycin, causes the accumulation of PINK1 on the outer mitochondrial membrane, a marked increase of pS65-ubiquitin and the recruitment of Parkin, which targets dysfunctional mitochondria for degradation by autophagy. While the high penetrance of PINK1 mutations establish its critical function for maintaining neurons, the activity of PINK1 in primary neurons has been difficult to detect. Mounting evidence implicates non-neuronal cells, including astrocytes and microglia, in the pathogenesis of both idiopathic and inherited PD. Herein we used both western analysis and immunofluorescence of pS65-ubiquitin to directly compare the activity of PINK1 in primary neurons, astrocytes, microglia, and oligodendrocyte progenitor cells cultured from the brains of wild-type (WT) and PINK1 knockout (KO) rat pups. Our findings that PINK1-dependent ubiquitin phosphorylation is predominantly in astrocytes supports increased priority for research on the function of PINK1 in astrocytes and the contribution of astrocyte dysfunction to PD pathogenesis.

scholarly journals A Mandibular Advancement Device Attenuates the Abnormal Morphology and Function of Mitochondria from the Genioglossus in OSAHS Rabbits

2021 ◽  
Author(s):  
Chunyan Liu ◽  
Shilong Zhang ◽  
Dechao Zhu ◽  
Dengying Fan ◽  
Yahui Zhu ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Complex I ◽  
Mitochondrial Membrane ◽  
Mandibular Advancement Device ◽  
Mandibular Advancement ◽  
Control Group ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
And Function

Abstract Background: To examine the morphology and function of mitochondria from the genioglossus in a rabbit model of obstructive sleep apnea-hypopnea syndrome (OSAHS), as well as these factors after insertion of a mandibular advancement device (MAD). Methods: Thirty male New Zealand white rabbits were randomized into three groups: control, OSAHS and MAD, with 10 rabbits in each group. Animals in Group OSAHS and Group MAD were induced to develop OSAHS by injection of gel into the submucosal muscular layer of the soft palate. The rabbits in Group MAD were fitted with a MAD. The animals in the control group were not treated. Further, polysomnography (PSG) and CBCT scan were used to measure MAD effectiveness. CBCT of the upper airway and PSG suggested that MAD was effective. Rabbits in the three groups were induced to sleep for 4–6 hours per day for 8 consecutive weeks. The genioglossus was harvested and detected by optical microscopy and transmission electron microscopy. The mitochondrial membrane potential was determined by laser confocal microscopy and flow cytometry. Mitochondrial complex I and IV activities were detected by mitochondrial complex assay kits.Results: OSAHS-like symptoms were induced successfully in Group OSAHS and rescued by MAD treatment. The relative values of the mitochondrial membrane potential, mitochondrial complex I activity and complex IV activity were significantly lower in Group OSAHS than in the control group; however, there was no significant difference between Group MAD and the control group. The OSAHS-induced injury and the dysfunctional mitochondria of the genioglossus muscle were reduced by MAD treatment.Conclusion: Damaged mitochondrial structure and function were induced by OSAHS and could be attenuated by MAD treatment.

Sign in / Sign up

Export Citation Format

Share Document