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Full-Text Articles in Cell Biology

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 ...


Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey Apr 2019

Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey

Biology ETDs

Properly executed cell division is crucial to development, maintenance, and longevity of multicellular organisms. Defects in both symmetric and asymmetric divisions can lead to improper developmental patterning, as well as genomic instability, disruption of tissue homeostasis, and cancer. Our research focuses on how regulators orchestrate proper cell divisions. Mushroom Body Defect (Mud) is one such regulator, and here we describe how Mud is regulated via the Hippo signaling pathway kinase Warts (Wts), showing Wts phosphorylates Mud to enhance interaction with the polarity protein Partner of Inscuteable, promoting spindle orientation activity. We next focus on another regulator, Shortstop (Shot), describing a ...


The Caspase Cascade During Hibernation In The Golden-Mantled Ground Squirrel, Spermophilus Lateralis, Michael David Treat May 2018

The Caspase Cascade During Hibernation In The Golden-Mantled Ground Squirrel, Spermophilus Lateralis, Michael David Treat

UNLV Theses, Dissertations, Professional Papers, and Capstones

In several human pathologies like heart attack, stroke, neurodegenerative diseases, and autoimmune disorders, widespread cell death, or apoptosis, is a major cause of organ dysfunction and death. Hibernating golden-mantled ground squirrels, Spermophilus lateralis, experience numerous conditions during the winter that are known to be pro-apoptotic in other mammal systems (e.g. extreme hypothermia, ischemia and reperfusion, acidosis, increased reactive oxygen species, bone and muscle disuse). However, studies suggest that hibernators may invoke a protective phenotype to limit widespread cell damage and loss during the hibernation season. Could regulating apoptosis provide protection against the harmful conditions experienced during the hibernation season ...


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 ...


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 ...


The Beneficial Role Of Extracellular Reactive Oxygen Species In Apoptosis-Induced Compensatory Proliferation, Neha Diwanji, Andreas Bergmann Aug 2016

The Beneficial Role Of Extracellular Reactive Oxygen Species In Apoptosis-Induced Compensatory Proliferation, Neha Diwanji, Andreas Bergmann

Molecular, Cell and Cancer Biology Publications

Apoptosis-induced proliferation (AiP) maintains tissue homeostasis following massive stress-induced cell death. During this phenomenon, dying cells induce proliferation of the surviving cells to compensate for the tissue loss, and thus restore organ size. Along with wound healing and tissue regeneration, AiP also contributes to tumor repopulation following radiation or chemotherapy. There are several models of AiP. Using an "undead" AiP model that causes hyperplastic overgrowth of Drosophila epithelial tissue, we recently demonstrated that extracellular reactive oxygen species (eROS) are produced by undead epithelial cells, and are necessary for inducing AiP and overgrowth. Furthermore, hemocytes, the Drosophila blood cells, are seen ...


Modulation Of Cell Death Signaling And Cell Proliferation By The Interaction Of Homoserine Lactones And Paraoxonase 2., Aaron Mackallan Neely May 2016

Modulation Of Cell Death Signaling And Cell Proliferation By The Interaction Of Homoserine Lactones And Paraoxonase 2., Aaron Mackallan Neely

Electronic Theses and Dissertations

Pseudomonas aeruginosa produces N-(3-oxododecanoyl)-homoserine lactone (C12) as a quorum-sensing molecule that functions to facilitate bacteria-bacteria communication. C12 has also been reported to affect many aspects of human host cell physiology, including evoking cell death in various types of cells. However, the signaling pathway(s) leading to C12-triggerred cell death remains unclear. To clarify cell death signaling induced by C12, we examined mouse embryonic fibroblasts (MEFs) deficient in one or more caspases. Our data indicate that, unlike most apoptotic inducers, C12 evokes a novel form of apoptosis in cells, probably through the direct induction of mitochondrial membrane permeabilization. Previous ...


Investigation Of Novel Functions For Dna Damage Response And Repair Proteins In Escherichia Coli And Humans, Benjamin A. Hilton May 2016

Investigation Of Novel Functions For Dna Damage Response And Repair Proteins In Escherichia Coli And Humans, Benjamin A. Hilton

Electronic Theses and Dissertations

Endogenous and exogenous agents that can damage DNA are a constant threat to genome stability in all living cells. In response, cells have evolved an array of mechanisms to repair DNA damage or to eliminate the cells damaged beyond repair. One of these mechanisms is nucleotide excision repair (NER) which is the major repair pathway responsible for removing a wide variety of bulky DNA lesions. Deficiency, or mutation, in one or several of the NER repair proteins is responsible for many diseases, including cancer. Prokaryotic NER involves only three proteins to recognize and incise a damaged site, while eukaryotic NER ...


Mir494 Reduces Renal Cancer Cell Survival Coinciding With Increased Lipid Droplets And Mitochondrial Changes, Punashi Dutta, Edward Haller, Arielle Sharp, Meera Nanjundan Jan 2016

Mir494 Reduces Renal Cancer Cell Survival Coinciding With Increased Lipid Droplets And Mitochondrial Changes, Punashi Dutta, Edward Haller, Arielle Sharp, Meera Nanjundan

Cell Biology, Microbiology, and Molecular Biology Faculty Publications

Background: miRNAs can regulate cellular survival in various cancer cell types. Recent evidence implicates the formation of lipid droplets as a hallmark event during apoptotic cell death response. It is presently unknown whether MIR494, located at 14q32 which is deleted in renal cancers, reduces cell survival in renal cancer cells and if this process is accompanied by changes in the number of lipid droplets.

Methods: 769-P renal carcinoma cells were utilized for this study. Control or MIR494 mimic was expressed in these cells following which cell viability (via crystal violet) and apoptotic cell numbers (via Annexin V/PI staining) were ...


Direct Regulation Of Apoptosis By Linear Ubiqutin Chain Assembly Complex (Lubac) And Feedback Regulation Of Lubac Function By Caspases, Donghyun Joo Aug 2015

Direct Regulation Of Apoptosis By Linear Ubiqutin Chain Assembly Complex (Lubac) And Feedback Regulation Of Lubac Function By Caspases, Donghyun Joo

UT GSBS Dissertations and Theses (Open Access)

Tumor Necrosis Factor-alpha (TNF-α) is a cytokine that plays a role in various cellular processes such as proliferation, differentiation (mainly through NF-κB signaling) and death (via apoptosis signaling). Recently, linear ubiquitination by LUBAC (linear ubiquitin chain assembly complex) was reported to have a regulatory function in TNF-α mediated NF-κB activation. Although LUBAC is suggested to control not only NF-kB signaling but also the apoptosis pathway, the precise mechanism of apoptosis regulation remains unknown. Moreover, NF-κB and apoptosis pathways have opposed but fundamental functions for various cellular processes. Although these two pathways actively interplay to balance the death and survival, the ...


Nuclear Pore Component Nup98 Is A Potential Tumor Suppressor And Regulates Posttranscriptional Expression Of Select P53 Target Genes, Stephan Singer, Ruiying Zhao, Anthony M. Barsotti, Anette Ouwehand, Mina Fazollahi, Elias Coutavas, Kai Breuhahn, Olaf Neumann, Thomas Longerich, Tobias Pusterla, Maureen A. Powers, Keith M. Giles, Peter J. Leedman, Jochen Hess, David Grunwald, Harmen J. Bussemaker, Robert H. Singer, Peter Schirmacher, Carol Prives Nov 2014

Nuclear Pore Component Nup98 Is A Potential Tumor Suppressor And Regulates Posttranscriptional Expression Of Select P53 Target Genes, Stephan Singer, Ruiying Zhao, Anthony M. Barsotti, Anette Ouwehand, Mina Fazollahi, Elias Coutavas, Kai Breuhahn, Olaf Neumann, Thomas Longerich, Tobias Pusterla, Maureen A. Powers, Keith M. Giles, Peter J. Leedman, Jochen Hess, David Grunwald, Harmen J. Bussemaker, Robert H. Singer, Peter Schirmacher, Carol Prives

David Grünwald

The p53 tumor suppressor utilizes multiple mechanisms to selectively regulate its myriad target genes, which in turn mediate diverse cellular processes. Here, using conventional and single-molecule mRNA analyses, we demonstrate that the nucleoporin Nup98 is required for full expression of p21, a key effector of the p53 pathway, but not several other p53 target genes. Nup98 regulates p21 mRNA levels by a posttranscriptional mechanism in which a complex containing Nup98 and the p21 mRNA 3'UTR protects p21 mRNA from degradation by the exosome. An in silico approach revealed another p53 target (14-3-3sigma) to be similarly regulated by Nup98. The ...


Elucidating The Signalling Pathway Of Mer Tyrosine Kinase Receptor In Efferocytosis, Ekenedelichukwu Azu Aug 2014

Elucidating The Signalling Pathway Of Mer Tyrosine Kinase Receptor In Efferocytosis, Ekenedelichukwu Azu

Electronic Thesis and Dissertation Repository

Efferocytosis is the clearance of apoptotic cells and is necessary for homeostasis. Mer Tyrosine Kinase (MerTK) is a crucial efferocytic receptor whose loss is associated with chronic inflammatory diseases and autoimmunity. While previous studies have shown that MerTK mediates efferocytosis through a unique mechanism that requires integrins, MerTK signalling pathway remains unknown. Given this unusual internalization mechanism, I hypothesized that MerTK signals and engages integrins through a novel signalling pathway different from that used by other phagocytic receptors. Therefore, this study aimed to identify the signalling pathways activated by MerTK, utilizing conventional cell biology and pharmacological approaches.

I found that ...


Regulation Of The Tumor Suppresser P53 And Survivin By Ras And Ral Gtpases:Implications For Malignant Transformation, Awet G. Tecleab Jan 2013

Regulation Of The Tumor Suppresser P53 And Survivin By Ras And Ral Gtpases:Implications For Malignant Transformation, Awet G. Tecleab

Graduate Theses and Dissertations

Abstract

Although the critical role of the small GTPases Ras and Ral in oncogenesis has been well documented, much remains to be investigated about the molecular mechanism by which these GTPases regulate malignant transformation. The work under this thesis made two major contributions to this field. The first is the discovery that K-Ras, RalA and/or RalB are required for the maintenance of the high levels of the anti-apoptotic protein survivin in some human cancer cells, and the second is the demonstration that down regulation of K-Ras, RalA and/or RalB, but not Raf-1 or Akt1/2, stabilizes the tumor ...


The Multifunctional Protein Daxx: Studies Of Its Biology And Regulation, And Discovery Of A Novel Function, Trisha Agrawal Jan 2013

The Multifunctional Protein Daxx: Studies Of Its Biology And Regulation, And Discovery Of A Novel Function, Trisha Agrawal

Publicly Accessible Penn Dissertations

Daxx, a multifunctional protein with a diverse set of proposed functions, is ubiquitously expressed and highly conserved through evolution. A primarily nuclear protein, Daxx is able to regulate apoptosis, transcription, and cellular proliferation. Despite many studies into the function of Daxx, its precise role in the cell remains enigmatic. Herein, evidence is presented to expand upon the known anti-apoptotic function of Daxx, to establish Daxx as a novel molecular chaperone, and to further its repertoire of transcriptional targets. As an apoptotic inhibitor, Daxx is known to regulate p53 by stabilizing its main negative regulator, Mdm2, via formation of a ternary ...


Combined Experimental And Computational Analysis Of Dna Damage Signaling Reveals Context-Dependent Roles For Erk In Apoptosis And G1/S Arrest After Genotoxic Stress, Andrea R. Tentner, Michael J. Lee, Gerry J. Ostheimer, Leona D. Samson, Douglas A. Lauffenburger, Michael B. Yaffe Jan 2012

Combined Experimental And Computational Analysis Of Dna Damage Signaling Reveals Context-Dependent Roles For Erk In Apoptosis And G1/S Arrest After Genotoxic Stress, Andrea R. Tentner, Michael J. Lee, Gerry J. Ostheimer, Leona D. Samson, Douglas A. Lauffenburger, Michael B. Yaffe

Program in Systems Biology Publications and Presentations

Following DNA damage, cells display complex multi-pathway signaling dynamics that connect cell-cycle arrest and DNA repair in G1, S, or G2/M phase with phenotypic fate decisions made between survival, cell-cycle re-entry and proliferation, permanent cell-cycle arrest, or cell death. How these phenotypic fate decisions are determined remains poorly understood, but must derive from integrating genotoxic stress signals together with inputs from the local microenvironment. To investigate this in a systematic manner, we undertook a quantitative time-resolved cell signaling and phenotypic response study in U2OS cells receiving doxorubicin-induced DNA damage in the presence or absence of TNFalpha co-treatment; we measured ...


Paternal Mitochondria Elimination And Cell Death Regulation In C. Elegans, Qinghua Zhou Jan 2012

Paternal Mitochondria Elimination And Cell Death Regulation In C. Elegans, Qinghua Zhou

Molecular, Cellular, and Developmental Biology Graduate Theses & Dissertations

The nematode C. elegans is a model organism for various biomedical studies due to its genetic simplicity and conservation with humans. As C. elegans is uniquely amenable to cellular, molecular genetic, and biochemical analyses, many basic biological processes are investigated by experimentally manipulating and observing worms. My thesis describes how I used C. elegans models to advance our understanding of paternal mitochondria elimination and cell death regulation.

Mitochondria are membrane-enclosed organelles that carry their own genome (mtDNA). In mammals, the inheritance of mitochondria and mtDNA is strictly maternal, despite the fact that a sperm can inject up to 100 functional ...


Hdm2 Small-Molecule Inhibitors For Therapeutic Intervention In B-Cell Lymphoma, Angela Sosin Jan 2012

Hdm2 Small-Molecule Inhibitors For Therapeutic Intervention In B-Cell Lymphoma, Angela Sosin

Wayne State University Dissertations

Lymphomas frequently retain wild-type (wt) p53 function but overexpress HDM2, compromising p53 activity. Therefore, lymphoma is a suitable model for studying therapeutic value of disrupting HDM2-p53 association by small-molecule inhibitors (SMIs). HDM2 SMIs have been developed and are currently under various stages of preclinical and clinical investigation. This study examined various molecular mechanisms associated and biological effects of two different classes of HDM2 SMIs: the spiro-oxindoles (MI-219) and cis-imidazoline (Nutlin-3) in lymphoma cell lines and patient-derived B-lymphoma cells. Surprisingly, results revealed significant quantitative and qualitative differences between these two agents. At the molecular level, effect of Nutlin-3 was generally more ...


Downregulation Of Pax2 Suppresses Ovarian Cancer Cell Growth, Huijuan Song Aug 2011

Downregulation Of Pax2 Suppresses Ovarian Cancer Cell Growth, Huijuan Song

UT GSBS Dissertations and Theses (Open Access)

PAX2 is one of nine PAX genes regulating tissue development and cellular differentiation in embryos. PAX2 promotes cell proliferation, oncogenic transformation, cell-lineage specification, migration, and survival. Unattenuated PAX2 has been found in several cancer types. We therefore sought to elucidate the role of PAX2 in ovarian carcinomas. We found that PAX2 was expressed in low-grade serous, clear cell, endometrioid and mucinous cell ovarian carcinomas, which are relatively chemoresistant compared to high grade serous ovarian carcinomas. Four ovarian cancer cell lines, RMUGL (mucinous), TOV21G (clear cell), MDAH-2774 (endometrioid) and IGROV1 (endometrioid), which express high-levels of PAX2, were used to study the ...


Nanosecond Pulsed Electric Field Induction Of Programmed Cell Death Is Cell Type Dependent: An In Vitro Study, Wei Ren Jul 2011

Nanosecond Pulsed Electric Field Induction Of Programmed Cell Death Is Cell Type Dependent: An In Vitro Study, Wei Ren

Theses and Dissertations in Biomedical Sciences

Nanosecond pulsed electric fields (nsPEFs) present a novel and effective method for cancer ablation by eradicating the ubiquitous cancer hallmark of apoptosis evasion and enforcing cancer programmed cell death. To develop nsPEFs as an anticancer method, a comprehensive understanding of cell death mechanisms is required. The overall objective of this dissertation is to elucidate molecular mechanisms underlying effects of nsPEFs on E4 murine squamous cell carcinoma and human T-cell Jurkat clones that are wildtype, deficient in FADD (ΔFADD) and deficient in caspase-8 (ACas-8). The overall hypothesis is that nsPEFs eliminate cancer cells through activating caspase-dependent and caspase-independent programmed cell death ...


Nanosecond Pulsed Electric Field Effects On Cell Cycle And Apoptosis, Emily H. Hall Apr 2006

Nanosecond Pulsed Electric Field Effects On Cell Cycle And Apoptosis, Emily H. Hall

Theses and Dissertations in Biomedical Sciences

Apoptosis, programmed cell death, is a highly regulated and complex pathway essential for embryonic development, immune-system function and maintenance of tissue homeostasis where cells induce their own cell death. Cells undergoing apoptosis exhibit a distinctive phenotype characterized by maintenance of membrane integrity, cell shrinkage, phosphatidylserine (PS) externalization at the plasma membrane, caspase protease activation, DNA fragmentation, release of cytochrome c from the mitochondrion, and membrane blebbing. An important regulatory protein in the apoptotic pathway is p53. The p53 protein functions to modulate the cell cycle by arresting cells in the G1 and G 2 phases to repair DNA damage, and ...


The Antitumor Agent, Arglabin-Dma, Preferentially Induces Apoptosis In Human Colon Tumor Cells, Sung Wook Kwon Apr 2005

The Antitumor Agent, Arglabin-Dma, Preferentially Induces Apoptosis In Human Colon Tumor Cells, Sung Wook Kwon

Theses and Dissertations in Biomedical Sciences

Arglabin-DMA, an analog of farnesyl pyrophosphate (FPP), reportedly inhibits farnesyltransferase (FTase) directly by competitively blocking the binding of Ras protein and its posttranslational modification, as suggested in previous studies. But, the mechanisms by which Arglabin-DMA inhibits tumor growth in vivo and in vitro are still relatively poorly characterized. To determine the mechanism by which this drug inhibits tumor growth, the effects of Arglabin-DMA in two human colon tumor cell lines (mutant K-ras HCT 116 and wild-type ras HT-29) were explored on cell proliferation, apoptosis, and cell cycle kinetics in vitro. In cell viability studies, we showed that Arglabin-DMA had ...