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Full-Text Articles in Life Sciences

Mechanistic Insights Into The Regulation Of Mitochondrial Fission By Cyclin C, Vidyaramanan Ganesan, Katrina F Cooper, Randy Strich Dec 2017

Mechanistic Insights Into The Regulation Of Mitochondrial Fission By Cyclin C, Vidyaramanan Ganesan, Katrina F Cooper, Randy Strich

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Cyclin C is a component of the mediator complex of RNA polymerase II that localizes to the nucleus under normal conditions. In response to stress, cyclin C translocates to the cytosol and mitochondria and mediates stress‐induced mitochondrial fission and apoptosis. The molecular mechanisms by which cyclin C induces mitochondrial fission are unknown. Using in vitro experimental approaches, we sought to investigate the mechanistic basis of cyclin C mediated mitochondrial fission.


Translocation Of Cyclin C During Oxidative Stress Is Regulated By Interactions With Multiple Trafficking Proteins, Daniel G J Smethurst, Katrina F Cooper, Randy Strich Dec 2017

Translocation Of Cyclin C During Oxidative Stress Is Regulated By Interactions With Multiple Trafficking Proteins, Daniel G J Smethurst, Katrina F Cooper, Randy Strich

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Eukaryotic cells take cues from their environment and interpret them to enact a response. External stresses can produce a decision between adjusting to behaviors which promote surviving the stress, or enacting a cell death program. The decision to undergo programmed cell death (PCD) is controlled by a complex interaction between nuclear and mitochondrial signals. The mitochondria are highly dynamic organelles that constantly undergo fission and fusion. However, a dramatic shift in mitochondrial morphology toward fission occurs early in the PCD process. We have identified the transcription factor cyclin C as the biochemical trigger for stress‐induced mitochondrial hyper‐fragmentation in yeast (Cooper …


The Role Of Mapk And Scf In The Destruction Of Med13 In Cyclin C Mediated Cell Death, David C Stieg, Stephen D Willis, Joseph Scuorzo, Mia Song, Vidyaramanan Ganesan, Randy Strich, Katrina F Cooper Dec 2017

The Role Of Mapk And Scf In The Destruction Of Med13 In Cyclin C Mediated Cell Death, David C Stieg, Stephen D Willis, Joseph Scuorzo, Mia Song, Vidyaramanan Ganesan, Randy Strich, Katrina F Cooper

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

In response to stress, the yeast1 and mammalian2 cyclin C translocate from the nucleus to the cytoplasm, where it associates with the GTPase Drp1/Dnm1 to drive mitochondrial fragmentation and apoptosis. Therefore, the decision to release cyclin C represents a key life or death decision. In unstressed cells, the cyclin C‐Cdk8 kinase regulates transcription by associating with the Mediator of RNA polymerase II. We previously reported that the Mediator component Med13 anchors cyclin C in the nucleus3. Loss of Med13 function leads to constitutive cytoplasmic localization of cyclin C, resulting in fragmented mitochondria, hypersensitivity to stress and …


Snf1 Dependent Destruction Of Med13 Is Required For Programmed Cell Death Following Oxidative Stress In Yeast, Stephen D Willis, David C Stieg, R. Shah, Randy Strich, Katrina F Cooper Dec 2017

Snf1 Dependent Destruction Of Med13 Is Required For Programmed Cell Death Following Oxidative Stress In Yeast, Stephen D Willis, David C Stieg, R. Shah, Randy Strich, Katrina F Cooper

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

All eukaryotic cells, when faced with unfavorable environmental conditions, have to decide whether to mount a survival or cell death response. The conserved cyclin C and its kinase partner Cdk8 play a key role in this decision. Both are members of the Cdk8 kinase module that, along with Med12 and Med13, associate with the core mediator complex of RNA polymerase II. In S. cerevisiae, oxidative stress triggers Med13 destruction1, which thereafter releases cyclin Ci nto the cytoplasm. Cytoplasmic cyclin C associates with mitochondria where it induces hyper-fragmentation and programmed cell death2. This suggests a model in …


Targeting Ribosome Assembly Factors Selectively Protects P53 Positive Cells From Chemotherapeutic Agents, Russell T. Sapio, Anastasiya Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J. Manna, N. Minkovsky, Dimitri G Pestov Dec 2017

Targeting Ribosome Assembly Factors Selectively Protects P53 Positive Cells From Chemotherapeutic Agents, Russell T. Sapio, Anastasiya Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J. Manna, N. Minkovsky, Dimitri G Pestov

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Many chemotherapeutic agents act in a nondiscriminatory fashion, targeting both cancerous and noncancerous cells in Sphase and Mphase. One approach to reduce the toxic side effects in normal tissue is to exploit the differences in p53 functionality between cancerous and noncancerous cells. For example, activating p53 signaling by nongenotoxic means can transiently arrest noncancerous p53 positive cells in G1 phase and protect them from the cytotoxic effects of chemotherapeutic drugs. However, since most cancerous cells have faulty p53 signaling, they will proceed to cycle, and continue to be affected by the drug. In this study we asked if this G1‐phase …


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 Faculty Scholarship

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. …


Endonucleolytic Cleavage In The Expansion Segment 7 Of 25s Rrna Is An Early Marker Of Low-Level Oxidative Stress In Yeast, Daniel Shedlovskiy, Jessica A Zinskie, Ethan Gardner, Dimitri G Pestov, Natalia Shcherbik Nov 2017

Endonucleolytic Cleavage In The Expansion Segment 7 Of 25s Rrna Is An Early Marker Of Low-Level Oxidative Stress In Yeast, Daniel Shedlovskiy, Jessica A Zinskie, Ethan Gardner, Dimitri G Pestov, Natalia Shcherbik

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The ability to detect and respond to oxidative stress is crucial to the survival of living organisms. In cells, sensing of increased levels of reactive oxygen species (ROS) activates many defensive mechanisms that limit or repair damage to cell components. The ROS-signaling responses necessary for cell survival under oxidative stress conditions remain incompletely understood, especially for the translational machinery. Here, we found that drug treatments or a genetic deficiency in the thioredoxin system that increase levels of endogenous hydrogen peroxide in the yeast Saccharomyces cerevisiae promote site-specific endonucleolytic cleavage in 25S ribosomal RNA (rRNA) adjacent to the c loop of …


Inhibition Of Post-Transcriptional Steps In Ribosome Biogenesis Confers Cytoprotection Against Chemotherapeutic Agents In A P53-Dependent Manner, Russell T Sapio, Anastasiya N Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J Manna, Natalie Minkovsky, Dimitri G Pestov Aug 2017

Inhibition Of Post-Transcriptional Steps In Ribosome Biogenesis Confers Cytoprotection Against Chemotherapeutic Agents In A P53-Dependent Manner, Russell T Sapio, Anastasiya N Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J Manna, Natalie Minkovsky, Dimitri G Pestov

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The p53-mediated nucleolar stress response associated with inhibition of ribosomal RNA transcription was previously shown to potentiate killing of tumor cells. Here, we asked whether targeting of ribosome biogenesis can be used as the basis for selective p53-dependent cytoprotection of nonmalignant cells. Temporary functional inactivation of the 60S ribosome assembly factor Bop1 in a 3T3 cell model markedly increased cell recovery after exposure to camptothecin or methotrexate. This was due, at least in part, to reversible pausing of the cell cycle preventing S phase associated DNA damage. Similar cytoprotective effects were observed after transient shRNA-mediated silencing of Rps19, but not …


Characterization Of Malt1 Inhibitors And Their Effect On Leukemic Cell Growth Properties, Christina Snyder Jan 2017

Characterization Of Malt1 Inhibitors And Their Effect On Leukemic Cell Growth Properties, Christina Snyder

Graduate School of Biomedical Sciences Theses and Dissertations

Leukemia is the most common childhood cancer, with a combined 40,000 predicted new cases in the United States in 2016 [8]. The two most common subtypes are acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL) [9-11]. The commercially available inhibitor of Bruton’s tyrosine kinase (BTK) has shown promising results in clinical trials for CLL because of the importance of BCR signaling in CLL [12-15]. Recent studies suggest that the outgrowth of BTK inhibitor resistant clonal cells in some CLL patients results in a treatment-refractory phenotype [16-18]. MALT1, a protein involved in BCR activation of the NF-κB pathway that functions …