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Full-Text Articles in Cell Biology

Uncovering Dual Roles For Perk Signaling During Experimentally Induced Pancreatitis, Elena Fazio Jun 2012

Uncovering Dual Roles For Perk Signaling During Experimentally Induced Pancreatitis, Elena Fazio

Electronic Thesis and Dissertation Repository

Pancreatitis is characterized by inappropriate activation of digestive enzyme

precursors, or zymogens, local and systemic inflammation, dysregulation of

cellular calcium (Ca2+), and induction of the unfolded protein response (UPR).

The UPR consists of three distinct pathways all of which are activated during

pancreatitis. However, the molecular roles of each remain unclear. The

protein kinase RNA (PKR)-like ER kinase (PERK) pathway reduces general

protein translation by phosphorylating eIF2!, and is activated within minutes

of initiating pancreatic damage. Microarray analysis carried out by our lab

revealed robust upregulation of the PERK pathways members Activating

Transcription Factor (ATF) 3 and stanniocalcin (STC ...


Identification And Characterization Of The Arabidopsis Homolog Of The Yeast Trex-2 Complex, Gang Tian May 2012

Identification And Characterization Of The Arabidopsis Homolog Of The Yeast Trex-2 Complex, Gang Tian

Electronic Thesis and Dissertation Repository

Nuclear pore complexes (NPCs) are vital to nuclear-cytoplasmic communication in eukaryotes. The yeast Thp1-Sac3-Cdc31-Sus1 complex, also known as the TREX-2 complex, is anchored to the NPC via the nucleoporin Nup1, and is essential for mRNA export. In this study, the Arabidopsis homolog of the yeast TREX-2 complex was discovered. Physical and functional evidence support the identification of the Arabidopsis orthologs of the yeast Thp1 and Nup1. Of three Sac3 Arabidopsis homologs, two are putative TREX-2 components. Surprisingly, none are required for mRNA export as is the yeast Sac3. Physical association with TREX-2 was observed for the two Cdc31 homologs, but ...


Target Recognition And Competitive Synaptogenesis In The Drosophila Giant Fiber System, Jason Joseph Hill May 2012

Target Recognition And Competitive Synaptogenesis In The Drosophila Giant Fiber System, Jason Joseph Hill

Open Access Dissertations

The development of complex neural networks relies on a careful balance of environmental cues to guide and shape both ends of the eventual connection. However, the correct wiring of circuits whose components share molecular profiles depends on a more elaborate phenomenon, competition. Despite being highly studied, there is still a lack of understanding as to the mechanism that allows molecularly identical cells to form exclusive connections with their targets. To address this complex question, we turned to a simple circuit within the genetically tractable fly. Responsible for the escape reflex, the Giant Fiber System is comprised of bilaterally symmetrical axons ...


Role Of Trp Channels In Mediating The Calcium Signaling Response Of Brain Endothelial Cells To Mechanical Stretch, Jonathan Berrout May 2012

Role Of Trp Channels In Mediating The Calcium Signaling Response Of Brain Endothelial Cells To Mechanical Stretch, Jonathan Berrout

UT GSBS Dissertations and Theses (Open Access)

Traumatic brain injury (TBI) often results in disruption of the blood brain barrier (BBB), which is an integral component to maintaining the central nervous system homeostasis. Recently cytosolic calcium levels ([Ca2+]i), observed to elevate following TBI, have been shown to influence endothelial barrier integrity. However, the mechanism by which TBI-induced calcium signaling alters the endothelial barrier remains unknown. In the present study, an in vitro BBB model was utilized to address this issue. Exposure of cells to biaxial mechanical stretch, in the range expected for TBI, resulted in a rapid cytosolic calcium increase. Modulation of intracellular and extracellular ...


Regulation Of Protein Degradation In The Heart By Amp-Activated Protein Kinase, Kedryn K. Baskin, Kedryn K. Baskin May 2012

Regulation Of Protein Degradation In The Heart By Amp-Activated Protein Kinase, Kedryn K. Baskin, Kedryn K. Baskin

UT GSBS Dissertations and Theses (Open Access)

The degradation of proteins by the ubiquitin proteasome system is essential for cellular homeostasis in the heart. An important regulator of metabolic homeostasis is AMP-activated protein kinase (AMPK). During nutrient deprivation, AMPK is activated and intracellular proteolysis is enhanced through the ubiquitin proteasome system (UPS). Whether AMPK plays a role in protein degradation through the UPS in the heart is not known. Here I present data in support of the hypothesis that AMPK transcriptionally regulates key players in the UPS, which, under extreme conditions can be detrimental to the heart. The ubiquitin ligases MAFbx /Atrogin-1 and MuRF1, key regulators of ...


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 ...


Synergy Between Insulin-Like Growth Factor-I (Igf-I) E-Peptides And Igf-I Signaling Alters Growth In Skeletal Muscle, Becky Kathleen Brisson Jan 2012

Synergy Between Insulin-Like Growth Factor-I (Igf-I) E-Peptides And Igf-I Signaling Alters Growth In Skeletal Muscle, Becky Kathleen Brisson

Publicly Accessible Penn Dissertations

Insulin-like growth factor-I (IGF-I) is a potent growth factor that regulates and promotes growth in many types of cells and tissues, including skeletal muscle. The igf1 gene encodes mature IGF-I and a carboxy-terminal extension called the E-peptide. In rodents, alternative splicing and post-translational processing produce two E-peptides (EA and EB). The mature IGF-I produced by both isoforms is identical, while EA and EB share less than 50% homology. EB has been studied extensively and has been reported to promote cell proliferation and migration independently of IGF-I and its receptor (IGF-IR) in culture, but the mechanism by which EB causes these ...


The Effect Of Exercise On Endothelin And Endothelin Receptor Levels In Shr And Wky Male And Female Rats, Lacey Stiller Jan 2012

The Effect Of Exercise On Endothelin And Endothelin Receptor Levels In Shr And Wky Male And Female Rats, Lacey Stiller

All Theses, Dissertations, and Other Capstone Projects

The role of exercise as a means to modulate renal function in hypertension is unclear. However, prior studies in the laboratory of Dr. Penny Knoblich indicate that exercised female spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats excrete significantly more sodium in response to a rise in blood pressure relative to exercised male and sedentary female SHR and WKY rats. The purpose of this study was to evaluate the effects of exercise on endothelin and endothelin receptor levels in the urine and kidneys of male and female SHR and WKY rats, to elucidate potential mechanisms to explain an increase ...


A Proposal To Test The Effects Of Factor Ecat1 On Pluripotency, From Reprogramming To Differentiation Of Human Somatic Cells, Vritti R. Goel Jan 2012

A Proposal To Test The Effects Of Factor Ecat1 On Pluripotency, From Reprogramming To Differentiation Of Human Somatic Cells, Vritti R. Goel

CMC Senior Theses

The field of stem cell research has been growing more because of the interest in using stem cells to cure diseases and heal injuries. Human embryonic stem cells, because of the controversy surrounding them—and subsequently the difficulties in acquiring samples of the existing aging cell lines—can only be used in limited capacities. While the development of induced pluripotent stem cells in the last decade has allowed the field to progress closer to medical treatments, the low efficiency of reprogramming a somatic cell to a pluripotent state, and the vast molecular and genomic differences between human embryonic stem cells ...