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Articles 1 - 11 of 11

Full-Text Articles in Cell Biology

Expression Of Mitochondrial Membrane-Linked Sab Determines Severity Of Sex-Dependent Acute Liver Injury, Sanda Win, Robert W. M. Min, Christopher Q. Chen, Jun Zhang, Yibu Chen, Meng Li, Ayako Suzuki, Manal F. Abdelmalek, Ying Wang, Mariam Aghajan, Filbert W. M. Aung, Anna Mae Diehl, Roger J. Davis, Tin A. Than, Neil Kaplowitz Sep 2019

Expression Of Mitochondrial Membrane-Linked Sab Determines Severity Of Sex-Dependent Acute Liver Injury, Sanda Win, Robert W. M. Min, Christopher Q. Chen, Jun Zhang, Yibu Chen, Meng Li, Ayako Suzuki, Manal F. Abdelmalek, Ying Wang, Mariam Aghajan, Filbert W. M. Aung, Anna Mae Diehl, Roger J. Davis, Tin A. Than, Neil Kaplowitz

University of Massachusetts Medical School Faculty Publications

SAB is an outer membrane docking protein for JNK mediated impaired mitochondrial function. Deletion of Sab in hepatocytes inhibits sustained JNK activation and cell death. Current work demonstrated that increasing SAB enhanced the severity of APAP liver injury. Female mice were resistant to liver injury and exhibited markedly decreased hepatic SAB protein expression versus males. The mechanism of SAB repression involved a pathway from ERalpha to p53 expression which induced miR34a-5p. miR34a-5p targeted the Sab mRNA coding region, repressing SAB expression. Fulvestrant or p53 knockdown decreased miR34a-5p and increased SAB in females leading to increased injury from APAP and TNF ...


Atf6alpha Impacts Cell Number By Influencing Survival, Death And Proliferation, Rohit B. Sharma, Jarin T. Snyder, Laura C. Alonso Sep 2019

Atf6alpha Impacts Cell Number By Influencing Survival, Death And Proliferation, Rohit B. Sharma, Jarin T. Snyder, Laura C. Alonso

Open Access Articles

BACKGROUND: A growing body of literature suggests the cell-intrinsic activity of Atf6alpha during ER stress responses has implications for tissue cell number during growth and development, as well as in adult biology and tumorigenesis [1]. This concept is important, linking the cellular processes of secretory protein synthesis and endoplasmic reticulum stress response with functional tissue capacity and organ size. However, the field contains conflicting observations, especially notable in secretory cell types like the pancreatic beta cell.

SCOPE OF REVIEW: Here we summarize current knowledge of the basic biology of Atf6alpha, along with the pleiotropic roles Atf6alpha plays in cell life ...


Activation Of The Apoptotic Pathway During Prolonged Prometaphase Blocks Daughter Cell Proliferation, Yumi Uetake, Greenfield Sluder Nov 2018

Activation Of The Apoptotic Pathway During Prolonged Prometaphase Blocks Daughter Cell Proliferation, Yumi Uetake, Greenfield Sluder

Radiology Publications and Presentations

When untransformed human cells spend >1.5 hr. in prometaphase under standard culture conditions, all daughters arrest in G1 despite normal division of their mothers. We investigate what happens during prolonged prometaphase that leads to daughter cell arrest in the absence of DNA damage. We find that progressive loss of anti-apoptotic MCL-1 activity and oxidative stress act in concert to partially activate the apoptosis pathway resulting in the delayed death of some daughters and senescence for the rest. At physiological oxygen levels, longer prometaphase durations are needed for all daughters to arrest. Partial activation of apoptosis during prolonged prometaphase leads ...


Jnk Promotes Epithelial Cell Anoikis By Transcriptional And Post-Translational Regulation Of Bh3-Only Proteins, Nomeda Girnius, Roger J. Davis Nov 2017

Jnk Promotes Epithelial Cell Anoikis By Transcriptional And Post-Translational Regulation Of Bh3-Only Proteins, Nomeda Girnius, Roger J. Davis

UMass Metabolic Network Publications

Developmental morphogenesis, tissue injury, and oncogenic transformation can cause the detachment of epithelial cells. These cells are eliminated by a specialized form of apoptosis (anoikis). While the processes that contribute to this form of cell death have been studied, the underlying mechanisms remain unclear. Here, we tested the role of the cJUN NH2-terminal kinase (JNK) signaling pathway using murine models with compound JNK deficiency in mammary and kidney epithelial cells. These studies demonstrated that JNK is required for efficient anoikis in vitro and in vivo. Moreover, JNK-promoted anoikis required pro-apoptotic members of the BCL2 family of proteins. We show that ...


Regulation Of Ripk1 Activation By Tak1-Mediated Phosphorylation Dictates Apoptosis And Necroptosis, Jiefei Geng, Yasushi Ito, Linyu Shi, Palak Amin, Jiachen Chu, Amanda Tomie Ouchida, Adnan Kasim Mookhtiar, Heng Zhao, Daichao Xu, Bing Shan, Ayaz Najafov, Guangping Gao, Shizuo Akira, Junying Yuan Aug 2017

Regulation Of Ripk1 Activation By Tak1-Mediated Phosphorylation Dictates Apoptosis And Necroptosis, Jiefei Geng, Yasushi Ito, Linyu Shi, Palak Amin, Jiachen Chu, Amanda Tomie Ouchida, Adnan Kasim Mookhtiar, Heng Zhao, Daichao Xu, Bing Shan, Ayaz Najafov, Guangping Gao, Shizuo Akira, Junying Yuan

Open Access Articles

Stimulation of TNFR1 by TNFalpha can promote three distinct alternative mechanisms of cell death: necroptosis, RIPK1-independent and -dependent apoptosis. How cells decide which way to die is unclear. Here, we report that TNFalpha-induced phosphorylation of RIPK1 in the intermediate domain by TAK1 plays a key role in regulating this critical decision. Using phospho-Ser321 as a marker, we show that the transient phosphorylation of RIPK1 intermediate domain induced by TNFalpha leads to RIPK1-independent apoptosis when NF-kappaB activation is inhibited by cycloheximide. On the other hand, blocking Ser321 phosphorylation promotes RIPK1 activation and its interaction with FADD to mediate RIPK1-dependent apoptosis (RDA ...


Killers Creating New Life: Caspases Drive Apoptosis-Induced Proliferation In Tissue Repair And Disease, Caitlin E. Fogarty, Andreas Bergmann Aug 2017

Killers Creating New Life: Caspases Drive Apoptosis-Induced Proliferation In Tissue Repair And Disease, Caitlin E. Fogarty, Andreas Bergmann

Open Access Articles

Apoptosis is a carefully orchestrated and tightly controlled form of cell death, conserved across metazoans. As the executioners of apoptotic cell death, cysteine-dependent aspartate-directed proteases (caspases) are critical drivers of this cellular disassembly. Early studies of genetically programmed cell death demonstrated that the selective activation of caspases induces apoptosis and the precise elimination of excess cells, thereby sculpting structures and refining tissues. However, over the past decade there has been a fundamental shift in our understanding of the roles of caspases during cell death-a shift precipitated by the revelation that apoptotic cells actively engage with their surrounding environment throughout the ...


Differential Involvement Of The Microtubule Cytoskeleton In Insulin Receptor Substrate 1 (Irs-1) And Irs-2 Signaling To Akt Determines The Response To Microtubule Disruption In Breast Carcinoma Cells, Jose Mercado-Matos, Jennifer L. Clark, Andrew J. Piper, Jenny Janusis, Leslie M. Shaw May 2017

Differential Involvement Of The Microtubule Cytoskeleton In Insulin Receptor Substrate 1 (Irs-1) And Irs-2 Signaling To Akt Determines The Response To Microtubule Disruption In Breast Carcinoma Cells, Jose Mercado-Matos, Jennifer L. Clark, Andrew J. Piper, Jenny Janusis, Leslie M. Shaw

UMass Metabolic Network Publications

The insulin receptor substrate (IRS) proteins serve as essential signaling intermediates for the activation of PI3K by both the insulin-like growth factor 1 receptor (IGF-1R) and its close family member, the insulin receptor (IR). Although IRS-1 and IRS-2 share significant homology, they regulate distinct cellular responses downstream of these receptors and play divergent roles in breast cancer. To investigate the mechanism by which signaling through IRS-1 and IRS-2 results in differential outcomes, we assessed the involvement of the microtubule cytoskeleton in IRS-dependent signaling. Treatment with drugs that either stabilize or disrupt microtubules reveal that an intact microtubule cytoskeleton contributes to ...


Mitochondrial Dynamics: Exploring A Novel Target Against Myocardial Ischemia-Reperfusion Injury, Yi Dong Jan 2014

Mitochondrial Dynamics: Exploring A Novel Target Against Myocardial Ischemia-Reperfusion Injury, Yi Dong

Wayne State University Dissertations

Mitochondrial fusion and fission, collectively termed mitochondrial dynamics, are among the core mechanisms responsible for maintaining mitochondrial health and functional integrity. Dynamin-related protein 1 (DRP1) is a key regulator of mitochondrial fission. Recent studies suggest that i) mitochondrial dynamics, particularly, mitochondrial fission, serves as a mediator of cell fate in the setting of ischemia-reperfusion (IR) injury, and, ii) inhibition of DRP1 and mitochondrial fission provides cardioprotection against IR injury. However, the precise role of DRP1 translocation to mitochondria in the pathogenesis of myocardial ischemia-reperfusion injury has not been established.

Using an established model of hypoxia-reoxygenation (HR) in cultured HL-1 cardiomyocytes ...


A Novel Autophagy Regulatory Mechanism That Functions During Programmed Cell Death: A Dissertation, Tsun-Kai Chang Sep 2013

A Novel Autophagy Regulatory Mechanism That Functions During Programmed Cell Death: A Dissertation, Tsun-Kai Chang

GSBS Dissertations and Theses

Autophagy is a cellular process that delivers cytoplasmic materials for degradation by the lysosomes. Autophagy-related (Atg) genes were identified in yeast genetic screens for vehicle formation under stress conditions, and Atg genes are conserved from yeast to human. When cells or animals are under stress, autophagy is induced and Atg8 (LC3 in mammal) is activated by E1 activating enzyme Atg7. Atg8-containing membranes form and surround cargos, close and mature to become the autophagosomes. Autophagosomes fuse with lysosomes, and cargos are degraded by lysosomal enzymes to sustain cell viability. Therefore, autophagy is most frequently considered to function in cell survival. Whether ...


Intrinsic Apoptotic Pathway: Effects Of Calcium On Murine Cytochrome C Release In Brain And Liver Mitochondria, Dane M. Edwards Apr 2013

Intrinsic Apoptotic Pathway: Effects Of Calcium On Murine Cytochrome C Release In Brain And Liver Mitochondria, Dane M. Edwards

Senior Honors Theses

A cell may use one of three main apoptotic pathways leading to programmed cell death: the extrinsic pathway, the perforin/granzyme pathway and the intrinsic pathway. The most pertinent to this discussion is the intrinsic pathway, which utilizes the mitochondria as an essential intermediary. Mitochondria’s primary function in relation to this pathway is the subsequent release of pro-apoptotic factors including cytochrome c, which activate a caspase cascade leading to the death of the cell. Cytochrome c is released partly due to an increase in cytosolic calcium levels. Two methods of the release of cytochrome c have been proposed. The ...


Treatment Of Aortic Heart Valve Conduit With Glutamine And Heat Shock As A Means To Deter The Constituent Cellular Population From Becoming Apoptotic, Alyce Marie Linthurst Jones Apr 2012

Treatment Of Aortic Heart Valve Conduit With Glutamine And Heat Shock As A Means To Deter The Constituent Cellular Population From Becoming Apoptotic, Alyce Marie Linthurst Jones

Theses and Dissertations in Biomedical Sciences

Cryopreserved allograft heart valves represent the best solution for a patient with a failing heart valve. However, the constituent cells become apoptotic and within months of transplant the heart valve becomes acellular and the recipient's cells do not repopulate the allograft (3, 51). A strategy to prevent this situation would be to minimize or prevent apoptosis from occurring by strategically altering steps during heart valve processing. Recently it has been demonstrated that: 1) Heat shock protein 70 is a negative modulator of the apoptotic cascade; 2) Cells in culture exposed to hypothermic conditions produce heat shock protein 70 upon ...