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Mitochondria

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Articles 31 - 51 of 51

Full-Text Articles in Medical Cell Biology

Micu1 Interacts With The D-Ring Of The Mcu Pore To Control Its Ca2+ Flux And Sensitivity To Ru360, Melanie Paillard, György Csordás, Kai-Ting Huang, Peter Várnai, Suresh K. Joseph, György Hajnóczky Nov 2018

Micu1 Interacts With The D-Ring Of The Mcu Pore To Control Its Ca2+ Flux And Sensitivity To Ru360, Melanie Paillard, György Csordás, Kai-Ting Huang, Peter Várnai, Suresh K. Joseph, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Proper control of the mitochondrial Ca2+ uniporter’s pore (MCU) is required to allow Ca2+ dependent activation of oxidative metabolism and to avoid mitochondrial Ca2+ overload and cell death. The MCU’s gatekeeping and cooperative activation is mediated by the Ca2+ sensing MICU1 protein, which has been proposed to form dimeric complexes anchored to the EMRE scaffold of MCU. We unexpectedly find that MICU1 suppresses inhibition of MCU by ruthenium red/Ru360, which bind to MCU’s DIME motif, the selectivity filter. This led us to recognize in MICU1’s sequence, a putative DIME Interacting Domain (DID) which is required for …


Gender- And Region-Specific Changes In Estrogen Signaling In Aging Rat Brain Mitochondria, Christopher M. Evola, Tanner L. Hudson, Luping Huang, Adrian M. Corbett, Debra A. Mayes Aug 2018

Gender- And Region-Specific Changes In Estrogen Signaling In Aging Rat Brain Mitochondria, Christopher M. Evola, Tanner L. Hudson, Luping Huang, Adrian M. Corbett, Debra A. Mayes

Neuroscience, Cell Biology & Physiology Faculty Publications

Recently epidemiological studies suggest females lose neuroprotection from neurodegenerative diseases as they go through menopause. It has been hypothesized that this neuroprotection is hormone‐dependent. The current study characterized cell signaling molecules downstream of estrogen receptor beta that are known to play a role in memory, PKC, ERK, and connexin‐43, in regions of the brain associated with memory decline in an attempt to elucidate significant changes that occur post‐estrus. Total whole cell lysates were compared to isolated mitochondrial protein because mitochondrial function is known to be altered during aging. As hypothesized, protein concentrations differed depending on age, gender, and brain region. …


Mechanism Of Transcription Anti-Termination In Human Mitochondria., Hauke S Hillen, Andrey V Parshin, Karen Agaronyan, Yaroslav I Morozov, James J Graber, Aleksandar Chernev, Kathrin Schwinghammer, Henning Urlaub, Michael Anikin, Patrick Cramer, Dmitry Temiakov Nov 2017

Mechanism Of Transcription Anti-Termination In Human Mitochondria., Hauke S Hillen, Andrey V Parshin, Karen Agaronyan, Yaroslav I Morozov, James J Graber, Aleksandar Chernev, Kathrin Schwinghammer, Henning Urlaub, Michael Anikin, Patrick Cramer, Dmitry Temiakov

Rowan-Virtua School of Osteopathic Medicine Departmental Research

In human mitochondria, transcription termination events at a G-quadruplex region near the replication origin are thought to drive replication of mtDNA by generation of an RNA primer. This process is suppressed by a key regulator of mtDNA-the transcription factor TEFM. We determined the structure of an anti-termination complex in which TEFM is bound to transcribing mtRNAP. The structure reveals interactions of the dimeric pseudonuclease core of TEFM with mobile structural elements in mtRNAP and the nucleic acid components of the elongation complex (EC). Binding of TEFM to the DNA forms a downstream "sliding clamp," providing high processivity to the EC. …


Ros Control Mitochondrial Motility Through P38 And The Motor Adaptor Miro/Trak., Valentina Debattisti, Akos A. Gerencser, Masao Saotome, Sudipto Das, György Hajnóczky Nov 2017

Ros Control Mitochondrial Motility Through P38 And The Motor Adaptor Miro/Trak., Valentina Debattisti, Akos A. Gerencser, Masao Saotome, Sudipto Das, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitochondrial distribution and motility are recognized as central to many cellular functions, but their regulation by signaling mechanisms remains to be elucidated. Here, we report that reactive oxygen species (ROS), either derived from an extracellular source or intracellularly generated, control mitochondrial distribution and function by dose-dependently, specifically, and reversibly decreasing mitochondrial motility in both rat hippocampal primary cultured neurons and cell lines. ROS decrease motility independently of cytoplasmic [Ca2+], mitochondrial membrane potential, or permeability transition pore opening, known effectors of oxidative stress. However, multiple lines of genetic and pharmacological evidence support that a ROS-activated mitogen-activated protein kinase (MAPK), p38α, is …


Mitochondrial Ca(2+) Uptake By The Voltage-Dependent Anion Channel 2 Regulates Cardiac Rhythmicity., Hirohito Shimizu, Johann Schredelseker, Jie Huang, Kui Lu, Shamim Naghdi, Fei Lu, Sarah Franklin, Hannah Dg Fiji, Kevin Wang, Huanqi Zhu, Cheng Tian, Billy Lin, Haruko Nakano, Amy Ehrlich, Junichi Nakai, Adam Z Stieg, James K Gimzewski, Atsushi Nakano, Joshua I. Goldhaber, Thomas M. Vondriska, György Hajnóczky, Ohyun Kwon, Jau-Nian Chen Jan 2015

Mitochondrial Ca(2+) Uptake By The Voltage-Dependent Anion Channel 2 Regulates Cardiac Rhythmicity., Hirohito Shimizu, Johann Schredelseker, Jie Huang, Kui Lu, Shamim Naghdi, Fei Lu, Sarah Franklin, Hannah Dg Fiji, Kevin Wang, Huanqi Zhu, Cheng Tian, Billy Lin, Haruko Nakano, Amy Ehrlich, Junichi Nakai, Adam Z Stieg, James K Gimzewski, Atsushi Nakano, Joshua I. Goldhaber, Thomas M. Vondriska, György Hajnóczky, Ohyun Kwon, Jau-Nian Chen

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Tightly regulated Ca(2+) homeostasis is a prerequisite for proper cardiac function. To dissect the regulatory network of cardiac Ca(2+) handling, we performed a chemical suppressor screen on zebrafish tremblor embryos, which suffer from Ca(2+) extrusion defects. Efsevin was identified based on its potent activity to restore coordinated contractions in tremblor. We show that efsevin binds to VDAC2, potentiates mitochondrial Ca(2+) uptake and accelerates the transfer of Ca(2+) from intracellular stores into mitochondria. In cardiomyocytes, efsevin restricts the temporal and spatial boundaries of Ca(2+) sparks and thereby inhibits Ca(2+) overload-induced erratic Ca(2+) waves and irregular contractions. We further show that overexpression …


Pancreas: Do All Roads Lead To Mitochondria?, Amit Mukherji, Omobola Onikoyi, Vasudeva G. Kamath Jan 2015

Pancreas: Do All Roads Lead To Mitochondria?, Amit Mukherji, Omobola Onikoyi, Vasudeva G. Kamath

Touro College of Osteopathic Medicine (Middletown) Publications and Research

Over several millions of years of evolution, mitochondria have transformed into specialized organelles. Today, they cannot live outside the cell nor can the host cell live without them, resulting in a symbiotic relationship. Richard Altmann, in 1894, documented them as cell organelles and called them “bioblasts”. Later, the term “mitochondria” itself was coined by Carl Benda in 1898. Ever since these findings, we in the field of medicine have learned a lot about this tiny organelle, but numerous aspects continue to be discovered. In this article, we will review the significance of this organelle in terms of pancreatic dysfunctions.


Targeting The Redox System To Overcome Mechanisms Of Drug Resistance In Chronic Lymphocytic Leukemia, Marcia A. Ogasawara Aug 2014

Targeting The Redox System To Overcome Mechanisms Of Drug Resistance In Chronic Lymphocytic Leukemia, Marcia A. Ogasawara

Dissertations and Theses (Open Access)

Chronic Lymphocytic Leukemia (CLL) is the most common form of leukemia diagnosed in Western countries and is characterized by clonal expansion of B cells. The clinical course of CLL is diverse and nearly 50% of patients present with chromosomal abnormalities. Deletion of the short arm on chromosome 17 (del17p) occurs in 5-7% of cases and presents with the shortest median survival time and often respond poorly to therapy. The tumor suppressor gene, TP53 is located on this region and it is well established that the p53 protein regulates multiple functions including: mitochondria biogenesis, response to DNA damage and redox balance. …


Novel Roles For Actin In Mitochondrial Fission, Anna L. Hatch, Pinar S. Gurel, Henry N. Higgs Jan 2014

Novel Roles For Actin In Mitochondrial Fission, Anna L. Hatch, Pinar S. Gurel, Henry N. Higgs

Dartmouth Scholarship

Mitochondrial dynamics, including fusion, fission and translocation, are crucial to cellular homeostasis, with roles in cellular polarity, stress response and apoptosis. Mitochondrial fission has received particular attention, owing to links with several neurodegenerative diseases. A central player in fission is the cytoplasmic dynamin-related GTPase Drp1, which oligomerizes at the fission site and hydrolyzes GTP to drive membrane ingression. Drp1 recruitment to the outer mitochondrial membrane (OMM) is a key regulatory event, which appears to require a pre-constriction step in which the endoplasmic reticulum (ER) and mitochondrion interact extensively, a process termed ERMD (ER-associated mitochondrial division). It is unclear how ER-mitochondrial …


Micu1 Controls Both The Threshold And Cooperative Activation Of The Mitochondrial Ca(2+) Uniporter., György Csordás, Tünde Golenár, Erin L Seifert, Kimberli J Kamer, Yasemin Sancak, Fabiana Perocchi, Cynthia Moffat, David Weaver, Sergio De La Fuente Perez, Roman Bogorad, Victor Koteliansky, Jeffrey Adijanto, Vamsi K Mootha, György Hajnóczky Jun 2013

Micu1 Controls Both The Threshold And Cooperative Activation Of The Mitochondrial Ca(2+) Uniporter., György Csordás, Tünde Golenár, Erin L Seifert, Kimberli J Kamer, Yasemin Sancak, Fabiana Perocchi, Cynthia Moffat, David Weaver, Sergio De La Fuente Perez, Roman Bogorad, Victor Koteliansky, Jeffrey Adijanto, Vamsi K Mootha, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitochondrial Ca(2+) uptake via the uniporter is central to cell metabolism, signaling, and survival. Recent studies identified MCU as the uniporter's likely pore and MICU1, an EF-hand protein, as its critical regulator. How this complex decodes dynamic cytoplasmic [Ca(2+)] ([Ca(2+)]c) signals, to tune out small [Ca(2+)]c increases yet permit pulse transmission, remains unknown. We report that loss of MICU1 in mouse liver and cultured cells causes mitochondrial Ca(2+) accumulation during small [Ca(2+)]c elevations but an attenuated response to agonist-induced [Ca(2+)]c pulses. The latter reflects loss of positive cooperativity, likely via the EF-hands. MICU1 faces the intermembrane space and responds to …


Metabolic Remodeling Of The Tumor Microenvironment: Migration Stimulating Factor (Msf) Reprograms Myofibroblasts Toward Lactate Production, Fueling Anabolic Tumor Growth., Valentina Carito, Gloria Bonuccelli, Ubaldo E Martinez-Outschoorn, Diana Whitaker-Menezes, Maria Cristina Caroleo, Erika Cione, Anthony Howell, Richard G Pestell, Michael P. Lisanti, Federica Sotgia Sep 2012

Metabolic Remodeling Of The Tumor Microenvironment: Migration Stimulating Factor (Msf) Reprograms Myofibroblasts Toward Lactate Production, Fueling Anabolic Tumor Growth., Valentina Carito, Gloria Bonuccelli, Ubaldo E Martinez-Outschoorn, Diana Whitaker-Menezes, Maria Cristina Caroleo, Erika Cione, Anthony Howell, Richard G Pestell, Michael P. Lisanti, Federica Sotgia

Department of Stem Cell Biology and Regenerative Medicine Faculty Papers & Presentations

Migration stimulating factor (MSF) is a genetically truncated N-terminal isoform of fibronectin that is highly expressed during mammalian development in fetal fibroblasts, and during tumor formation in human cancer-associated myofibroblasts. However, its potential functional role in regulating tumor metabolism remains unexplored. Here, we generated an immortalized fibroblast cell line that recombinantly overexpresses MSF and studied their properties relative to vector-alone control fibroblasts. Our results indicate that overexpression of MSF is sufficient to confer myofibroblastic differentiation, likely via increased TGF-b signaling. In addition, MSF activates the inflammation-associated transcription factor NFκB, resulting in the onset of autophagy/mitophagy, thereby driving glycolytic metabolism (L-lactate …


Two-Compartment Tumor Metabolism: Autophagy In The Tumor Microenvironment And Oxidative Mitochondrial Metabolism (Oxphos) In Cancer Cells., Ahmed F Salem, Diana Whitaker-Menezes, Zhao Lin, Ubaldo E. Martinez-Outshoorn, Herbert B Tanowitz, Mazhar Salim Al-Zoubi, Anthony Howell, Richard Pestell, Federica Sotgia, Michael P. Lisanti Jul 2012

Two-Compartment Tumor Metabolism: Autophagy In The Tumor Microenvironment And Oxidative Mitochondrial Metabolism (Oxphos) In Cancer Cells., Ahmed F Salem, Diana Whitaker-Menezes, Zhao Lin, Ubaldo E. Martinez-Outshoorn, Herbert B Tanowitz, Mazhar Salim Al-Zoubi, Anthony Howell, Richard Pestell, Federica Sotgia, Michael P. Lisanti

Department of Stem Cell Biology and Regenerative Medicine Faculty Papers & Presentations

Previously, we proposed a new paradigm to explain the compartment-specific role of autophagy in tumor metabolism. In this model, autophagy and mitochondrial dysfunction in the tumor stroma promotes cellular catabolism, which results in the production of recycled nutrients. These chemical building blocks and high-energy "fuels" would then drive the anabolic growth of tumors, via autophagy resistance and oxidative mitochondrial metabolism in cancer cells. We have termed this new form of stromal-epithelial metabolic coupling: "two-compartment tumor metabolism." Here, we stringently tested this energy-transfer hypothesis, by genetically creating (1) constitutively autophagic fibroblasts, with mitochondrial dysfunction or (2) autophagy-resistant cancer cells, with increased …


Autophagy And Senescence In Cancer-Associated Fibroblasts Metabolically Supports Tumor Growth And Metastasis Via Glycolysis And Ketone Production., Claudia Capparelli, Carmela Guido, Diana Whitaker-Menezes, Phd, Gloria Bonuccelli, Renee Balliet, Timothy G Pestell, Allison F Goldberg, Richard Pestell, Anthony Howell, Sharon Sneddon, Ruth Birbe, Aristotelis Tsirigos, Ubaldo E. Martinez-Outshoorn, Federica Sotgia, Michael P. Lisanti Jun 2012

Autophagy And Senescence In Cancer-Associated Fibroblasts Metabolically Supports Tumor Growth And Metastasis Via Glycolysis And Ketone Production., Claudia Capparelli, Carmela Guido, Diana Whitaker-Menezes, Phd, Gloria Bonuccelli, Renee Balliet, Timothy G Pestell, Allison F Goldberg, Richard Pestell, Anthony Howell, Sharon Sneddon, Ruth Birbe, Aristotelis Tsirigos, Ubaldo E. Martinez-Outshoorn, Federica Sotgia, Michael P. Lisanti

Department of Stem Cell Biology and Regenerative Medicine Faculty Papers & Presentations

Senescent fibroblasts are known to promote tumor growth. However, the exact mechanism remains largely unknown. An important clue comes from recent studies linking autophagy with the onset of senescence. Thus, autophagy and senescence may be part of the same physiological process, known as the autophagy-senescence transition (AST). To test this hypothesis, human fibroblasts immortalized with telomerase (hTERT-BJ1) were stably transfected with autophagy genes (BNIP3, CTSB or ATG16L1). Their overexpression was sufficient to induce a constitutive autophagic phenotype, with features of mitophagy, mitochondrial dysfunction and a shift toward aerobic glycolysis, resulting in L-lactate and ketone body production. Autophagic fibroblasts also showed …


Mitochondrial Oxidative Stress Drives Tumor Progression And Metastasis: Should We Use Antioxidants As A Key Component Of Cancer Treatment And Prevention?, Federica Sotgia, Ubaldo E Martinez-Outschoorn, Michael P Lisanti May 2011

Mitochondrial Oxidative Stress Drives Tumor Progression And Metastasis: Should We Use Antioxidants As A Key Component Of Cancer Treatment And Prevention?, Federica Sotgia, Ubaldo E Martinez-Outschoorn, Michael P Lisanti

Department of Stem Cell Biology and Regenerative Medicine Faculty Papers & Presentations

The functional role of oxidative stress in cancer pathogenesis has long been a hotly debated topic. A study published this month in BMC Cancer by Goh et al., directly addresses this issue by using a molecular genetic approach, via an established mouse animal model of human breast cancer. More specifically, alleviation of mitochondrial oxidative stress, via transgenic over-expression of catalase (an anti-oxidant enzyme) targeted to mitochondria, was sufficient to lower tumor grade (from high-to-low) and to dramatically reduce metastatic tumor burden by >12-fold. Here, we discuss these new findings and place them in the context of several other recent studies …


S-Glutathionylation Activates Stim1 And Alters Mitochondrial Homeostasis., Brian J Hawkins, Krishna M Irrinki, Karthik Mallilankaraman, Yu-Chin Lien, Youjun Wang, Cunnigaiper D Bhanumathy, Ramasamy Subbiah, Michael F Ritchie, Jonathan Soboloff, Yoshihiro Baba, Tomohiro Kurosaki, Suresh K Joseph, Donald L Gill, Muniswamy Madesh Aug 2010

S-Glutathionylation Activates Stim1 And Alters Mitochondrial Homeostasis., Brian J Hawkins, Krishna M Irrinki, Karthik Mallilankaraman, Yu-Chin Lien, Youjun Wang, Cunnigaiper D Bhanumathy, Ramasamy Subbiah, Michael F Ritchie, Jonathan Soboloff, Yoshihiro Baba, Tomohiro Kurosaki, Suresh K Joseph, Donald L Gill, Muniswamy Madesh

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Oxidant stress influences many cellular processes, including cell growth, differentiation, and cell death. A well-recognized link between these processes and oxidant stress is via alterations in Ca(2+) signaling. However, precisely how oxidants influence Ca(2+) signaling remains unclear. Oxidant stress led to a phenotypic shift in Ca(2+) mobilization from an oscillatory to a sustained elevated pattern via calcium release-activated calcium (CRAC)-mediated capacitive Ca(2+) entry, and stromal interaction molecule 1 (STIM1)- and Orai1-deficient cells are resistant to oxidant stress. Functionally, oxidant-induced Ca(2+) entry alters mitochondrial Ca(2+) handling and bioenergetics and triggers cell death. STIM1 is S-glutathionylated at cysteine 56 in response to …


Elucidating A Normal Function Of Huntingtin By Functional And Microarray Analysis Of Huntingtin-Null Mouse Embryonic Fibroblasts., Hua Zhang, Sudipto Das, Quan-Zhen Li, Ioannis Dragatsis, Joyce Repa, Scott Zeitlin, György Hajnóczky, Ilya Bezprozvanny Jan 2008

Elucidating A Normal Function Of Huntingtin By Functional And Microarray Analysis Of Huntingtin-Null Mouse Embryonic Fibroblasts., Hua Zhang, Sudipto Das, Quan-Zhen Li, Ioannis Dragatsis, Joyce Repa, Scott Zeitlin, György Hajnóczky, Ilya Bezprozvanny

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The polyglutamine expansion in huntingtin (Htt) protein is a cause of Huntington's disease (HD). Htt is an essential gene as deletion of the mouse Htt gene homolog (Hdh) is embryonic lethal in mice. Therefore, in addition to elucidating the mechanisms responsible for polyQ-mediated pathology, it is also important to understand the normal function of Htt protein for both basic biology and for HD. RESULTS: To systematically search for a mouse Htt function, we took advantage of the Hdh +/- and Hdh-floxed mice and generated four mouse embryonic fibroblast (MEF) cells lines which contain a single copy of the Hdh …


A Novel Inhibitory Mechanism Of Mitochondrion-Dependent Apoptosis By A Herpesviral Protein, Pinghui Feng, Chengyu Liang, Young C. Shin, Xiaofei E, Weijun Zhang, Robyn Gravel, Ting-Ting Wu, Ren Sun, Edward Usherwood, Jae U. Jung Dec 2007

A Novel Inhibitory Mechanism Of Mitochondrion-Dependent Apoptosis By A Herpesviral Protein, Pinghui Feng, Chengyu Liang, Young C. Shin, Xiaofei E, Weijun Zhang, Robyn Gravel, Ting-Ting Wu, Ren Sun, Edward Usherwood, Jae U. Jung

Dartmouth Scholarship

Upon viral infection, cells undergo apoptosis as a defense against viral replication. Viruses, in turn, have evolved elaborate mechanisms to subvert apoptotic processes. Here, we report that a novel viral mitochondrial anti-apoptotic protein (vMAP) of murine gamma-herpesvirus 68 (gammaHV-68) interacts with Bcl-2 and voltage-dependent anion channel 1 (VDAC1) in a genetically separable manner. The N-terminal region of vMAP interacted with Bcl-2, and this interaction markedly increased not only Bcl-2 recruitment to mitochondria but also its avidity for BH3-only pro-apoptotic proteins, thereby suppressing Bax mitochondrial translocation and activation. In addition, the central and C-terminal hydrophobic regions of vMAP interacted with VDAC1. …


Combined Effects Of Aldehyde Dehydrogenase Variants And Maternal Mitochondrial Genes On Alcohol Consumption, Yedy Israel, Maria E. Quintanilla, Amalia Sapag, Lutske Tampier Dec 2006

Combined Effects Of Aldehyde Dehydrogenase Variants And Maternal Mitochondrial Genes On Alcohol Consumption, Yedy Israel, Maria E. Quintanilla, Amalia Sapag, Lutske Tampier

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Two lines of rats bred to differ in their voluntary alcohol consumption — the alcohol-abstaining UChA rats and the alcohol-drinking UChB rats — differ in how effectively toxic acetaldehyde is removed during alcohol metabolism. UChB animals carry efficient variants of the aldehyde dehydrogenase 2 (ALDH2) genes and have active mitochondria, resulting in fast removal of acetaldehyde. UChA animals, in contrast, carry less efficient ALDH2 variants and less active mitochondria, which result in transient elevations of acetaldehyde levels after alcohol ingestion. Cross-breeding studies have demonstrated that the presence of active mitochondria inherited from UChB females can fully abolish the reduction of …


Selective Role For Superoxide In Insp3 Receptor-Mediated Mitochondrial Dysfunction And Endothelial Apoptosis., Muniswamy Madesh, Brian J Hawkins, Tatyana Milovanova, Cunnigaiper D Bhanumathy, Suresh K Joseph, Satish P Ramachandrarao, Kumar Sharma, Tomohiro Kurosaki, Aron B Fisher Sep 2005

Selective Role For Superoxide In Insp3 Receptor-Mediated Mitochondrial Dysfunction And Endothelial Apoptosis., Muniswamy Madesh, Brian J Hawkins, Tatyana Milovanova, Cunnigaiper D Bhanumathy, Suresh K Joseph, Satish P Ramachandrarao, Kumar Sharma, Tomohiro Kurosaki, Aron B Fisher

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Reactive oxygen species (ROS) play a divergent role in both cell survival and cell death during ischemia/reperfusion (I/R) injury and associated inflammation. In this study, ROS generation by activated macrophages evoked an intracellular Ca2+ ([Ca2+]i) transient in endothelial cells that was ablated by a combination of superoxide dismutase and an anion channel blocker. [Ca2+]i store depletion, but not extracellular Ca2+ chelation, prevented [Ca2+]i elevation in response to O2*- that was inositol 1,4,5-trisphosphate (InsP3) dependent, and cells lacking the three InsP3 receptor (InsP3R) isoforms failed to display the [Ca2+]i transient. Importantly, the O2*--triggered Ca2+ mobilization preceded a loss in mitochondrial membrane …


Control Of Mitochondrial Motility And Distribution By The Calcium Signal: A Homeostatic Circuit., Muqing Yi, David Weaver, György Hajnóczky Nov 2004

Control Of Mitochondrial Motility And Distribution By The Calcium Signal: A Homeostatic Circuit., Muqing Yi, David Weaver, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitochondria are dynamic organelles in cells. The control of mitochondrial motility by signaling mechanisms and the significance of rapid changes in motility remains elusive. In cardiac myoblasts, mitochondria were observed close to the microtubular array and displayed both short- and long-range movements along microtubules. By clamping cytoplasmic [Ca2+] ([Ca2+]c) at various levels, mitochondrial motility was found to be regulated by Ca2+ in the physiological range. Maximal movement was obtained at resting [Ca2+]c with complete arrest at 1-2 microM. Movement was fully recovered by returning to resting [Ca2+]c, and inhibition could be repeated with no apparent desensitization. The inositol 1,4,5-trisphosphate- or …


Vdac-Dependent Permeabilization Of The Outer Mitochondrial Membrane By Superoxide Induces Rapid And Massive Cytochrome C Release., M Madesh, György Hajnóczky Dec 2001

Vdac-Dependent Permeabilization Of The Outer Mitochondrial Membrane By Superoxide Induces Rapid And Massive Cytochrome C Release., M Madesh, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Enhanced formation of reactive oxygen species (ROS), superoxide (O2*-), and hydrogen peroxide (H2O2) may result in either apoptosis or other forms of cell death. Here, we studied the mechanisms underlying activation of the apoptotic machinery by ROS. Exposure of permeabilized HepG2 cells to O2*- elicited rapid and massive cytochrome c release (CCR), whereas H2O2 failed to induce any release. Both O2*- and H2O2 promoted activation of the mitochondrial permeability transition pore by Ca2+, but Ca2+-dependent pore opening was not required for O2*--induced CCR. Furthermore, O2*- alone evoked CCR without damage of the inner mitochondrial membrane barrier, as mitochondrial membrane potential …


Eliciting The Low-Activity Aldehyde Dehydrogenase Asian Phenotype By An Antisense Mechanism Results In An Aversion To Ethanol., E Garver, Tu Gc, Q N Cao, M Aini, F Zhou, Y Israel Sep 2001

Eliciting The Low-Activity Aldehyde Dehydrogenase Asian Phenotype By An Antisense Mechanism Results In An Aversion To Ethanol., E Garver, Tu Gc, Q N Cao, M Aini, F Zhou, Y Israel

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

A mutation in the gene encoding for the liver mitochondrial aldehyde dehydrogenase (ALDH2-2), present in some Asian populations, lowers or abolishes the activity of this enzyme and results in elevations in blood acetaldehyde upon ethanol consumption, a phenotype that greatly protects against alcohol abuse and alcoholism. We have determined whether the administration of antisense phosphorothioate oligonucleotides (ASOs) can mimic the low-activity ALDH2-2 Asian phenotype. Rat hepatoma cells incubated for 24 h with an antisense oligonucleotide (ASO-9) showed reductions in ALDH2 mRNA levels of 85% and ALDH2 (half-life of 22 h) activity of 55% equivalent to a >90% inhibition in ALDH2 …