Cell Biology Commons^™

Septin Filaments Exhibit A Dynamic, Paired Organization That Is Conserved From Yeast To Mammals, Bradley S. Demay, Xiaobo Bai, Louisa Howard, Patricia Occhipinti, Rebecca A. Meseroll, Elias T. Spiliotis, Rudolf Oldenbourg, Amy S. Gladfelter

Dartmouth Scholarship

The septins are conserved, GTP-binding proteins important for cytokinesis, membrane compartmentalization, and exocytosis. However, it is unknown how septins are arranged within higher-order structures in cells. To determine the organization of septins in live cells, we developed a polarized fluorescence microscopy system to monitor the orientation of GFP dipole moments with high spatial and temporal resolution. When GFP was fused to septins, the arrangement of GFP dipoles reflected the underlying septin organization. We demonstrated in a filamentous fungus, a budding yeast, and a mammalian epithelial cell line that septin proteins were organized in an identical highly ordered fashion. Fluorescence anisotropy …

Analysis Of Band 4.1b In Integrin-Mediated Cell Adhesion And Signaling, Youngsin Jung

Dissertations and Theses (Open Access)

Band 4.1B is a cytoskeletal adaptor protein that regulates various cellular behavior; however, the mechanisms by which Band 4.1B contributes to intracellular signaling are unclear. This project addresses in vivo and in vitro functions for Band 4.1B in integrin-mediated cell adhesion and signaling. Band 4.1B has been shown to bind to β8 integrin, although cooperative functions of these two proteins have not been determined. Here, functional links between β8 integrin and Band 4.1B were investigated using gene knockout strategies. Ablation of β8 integrin and Band 4.1B genes resulted in impaired cardiac morphogenesis, leading to embryonic lethality by E11.5. These embryos …

Intermediate Filaments Regulate Tissue Size And Stiffness In The Murine Lens, Douglas S. Fudge, John V. Mccuaig, Shannon Van Stralen, John F. Hess, Huan Wang, Richard T. Mathias, Paul G. Fitzgerald

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

PURPOSE. To define the contributions of the beaded filament (BF), a lens-specific intermediate filament (IF), to lens morphology and biomechanics.

METHODS. Wild-type and congenic CP49 knockout (KO) mice were compared by using electrophysiological, biomechanical, and morphometric approaches, to determine changes that occurred because of the absence of this cytoskeletal structure.

RESULTS. Electrophysiological assessment established that the fiber cells lacking the lens-specific IFs were indistinguishable from wild-type fiber cells. The CP49 KO mice exhibited lower stiffness, and an unexpected higher resilience than the wildtype lenses. The absence of these filaments resulted in lenses that were smaller, and exhibited a higher ratio …

The Role Of Phosphoinositide Signaling In Breast Cancer Metastasis Suppressor 1-Mediated Metastasis Suppression Of Human Breast Carcinoma Cells, Sitaram Harihar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Breast cancer is the most common non-skin cancer in women and the second most common cause of cancer-related death in U.S. women. Despite numerous advances in treatment strategies against breast cancer, the presence of undetected distant metastasis of the primary tumor remains the main cause of mortality. Current screening and detection methods such as mammograms are simply not sensitive enough to detect formation of metastasis. Further, currently available therapies against metastatic breast cancer do not provide a complete cure for the disease. Thus, understanding the biology and molecular factors involved in cancer metastasis will help aid in preventing the onset …

Design Of A Factorial Experiment With Randomization Restrictions To Assess Medical Device Performance On Vascular Tissue, Wiebke Diestelkamp, Carissa M. Krane, Margaret Pinnell

Biology Faculty Publications

Background: Energy-based surgical scalpels are designed to efficiently transect and seal blood vessels using thermal energy to promote protein denaturation and coagulation. Assessment and design improvement of ultrasonic scalpel performance relies on both in vivo and ex vivo testing. The objective of this work was to design and implement a robust, experimental test matrix with randomization restrictions and predictive statistical power, which allowed for identification of those experimental variables that may affect the quality of the seal obtained ex vivo.

Methods: The design of the experiment included three factors: temperature (two levels); the type of solution used to perfuse the …

Endo-Porter–Mediated Delivery Of Phosphorodiamidate Morpholino Oligos (Pmos) In Erythrocyte Suspension Cultures From Cope's Gray Treefrog Hyla Chrysoscelis, Venkateshwar Mutyam, Matthew V. Puccetti, James Frisbie, David L. Goldstein, Carissa M. Krane

Biology Faculty Publications

Cope's gray treefrog, Hyla chrysoscelis, is a freeze-tolerant anuran that accumulates cryoprotective glycerol during cold acclimation. H. chrysoscelis erythrocytes express the aquaglyceroporin HC-3, which facilitates transmembrane glycerol and water movement. Aquaglyceroporins have no pharmacological inhibitors, and no genetic knockout tools currently exist for H. chrysoscelis. A phosphorodiamidate morpholino oligo (PMO)–mediated expression knockdown approach was therefore pursued to provide a model for testing the role of HC-3. We describe a novel procedure optimized for specific, efficient knockdown of HC-3 expression in amphibian erythrocyte suspensions cultured at nonmammalian physiological temperatures using Endo-Porter. Our protocol includes three critical components: pre-incubation at 37°C, …

Atm Signaling To Tsc2: Mechanisms And Implications For Cancer Therapy, Angela Alexander

Dissertations and Theses (Open Access)

Ataxia telangiectasia mutated (ATM) is a critical component of the cellular response to DNA damage, where it acts as a damage sensor, and signals to a large network of proteins which execute the important tasks involved in responding to the damage, namely inducing cell cycle checkpoints, inducing DNA repair, modulating transcriptional responses, and regulating cell death pathways if the damage cannot be repaired faithfully. We have now discovered that an additional novel component of this ATM-dependent damage response involves induction of autophagy in response to oxidative stress. In contrast to DNA damage-induced ATM activation however, oxidative stress induced ATM, occurs …

Cop 9 Signalosome Subunit 6 Stabilizes Cop1, A Novel E3 Ubiquitin Ligase For 14-3-3Σ, Hyun Ho Choi

Dissertations and Theses (Open Access)

14-3-3σ, a gene upregulated by p53 in response to DNA damage, exists as part of a positive-feedback loop which activates p53 and is a human cancer epithelial marker downregulated in various cancer types. 14-3-3σ levels are critical for maintaining p53 activity in response to DNA damage and regulating signal mediator such as Akt. Here, we identify Mammalian Constitutive Photomorphogenic 1 (COP1) as a novel E3 ubiquitin ligase for targeting 14-3-3σ through proteasome degradation. We show for the first time that COP9 signalosome subunit 6 (CSN6) associates with COP1 and is involved in 14-3-3σ ubiquitin-mediated degradation. Mechanistic studies show that CSN6 …

Developmental And Cellular Functions Of Delta-Catenin, Dongmin Gu

Dissertations and Theses (Open Access)

Catenins have diverse and powerful roles in embryogenesis, homeostasis or disease progression, as best exemplified by the well-known beta-catenin. The less studied delta-catenin likewise contains a central Armadillo-domain. In common with other p120 sub-class members, it acts in a variety of intracellular compartments and modulates cadherin stability, small GTPase activities and gene transcription. In mammals, delta-catenin exhibits neural specific expression, with its knock-out in mice correspondingly producing cognitive defects and synaptic dysfunctions.

My work instead employed the amphibian, Xenopus laevis, to explore delta-catenin’s physiological functions in a distinct vertebrate system. Initial isolation and characterization indicated delta-catenin’s expression in Xenopus. Unlike …

Altered Responses To Endoplasmic Reticulum Stress In Pancreatic Cancer, Jennifer H. Choe

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) represents the fourth most common cause of cancer-associated death in the United States. Little progress has been made in understanding how proteotoxic stress affects rapidly proliferating pancreatic tumor cells. Endoplasmic reticulum (ER) stress occurs when protein homeostasis in the ER lumen is perturbed. ER stress activates the unfolded protein response (UPR) to reduce the protein load in the ER. Under conditions of moderate ER stress, the UPR promotes cell cycle arrest which allows time for successful protein load reduction and enables cell survival. However, under conditions of high levels of ER stress the UPR induces cellular …

The Role And Mechanism Of The Homeobox Gene Dlx4 In Transforming Growth Factor-B Resistance In Cancer, Bon Q. Trinh

Dissertations and Theses (Open Access)

Transforming growth factor-b (TGF-b) is a cytokine that plays essential roles in regulating embryonic development and tissue homeostasis. In normal cells, TGF-b exerts an anti-proliferative effect. TGF-b inhibits cell growth by controlling a cytostatic program that includes activation of the cyclin-dependent kinase inhibitors p15^Ink4B and p21^WAF1/Cip1 and repression of c-myc. In contrast to normal cells, many tumors are resistant to the anti-proliferative effect of TGF-b. In several types of tumors, particularly those of gastrointestinal origin, resistance to the anti-proliferative effect of TGF-b has been attributed to TGF-b receptor or Smad mutations. However, these mutations are absent from many …

A Novel Function For Aurora B Kinase In The Regulation Of P53 By Phosphorylation, Chris P. Gully

Dissertations and Theses (Open Access)

The mitotic kinase Aurora B plays a pivotal role in mitosis and cytokinesis and governs the spindle assembly checkpoint which ensures correct chromosome segregation and normal progression through mitosis.  Aurora B is overexpressed in breast and other cancers and may be an important molecular target for chemotherapy.  Tumor suppressor p53 is the guardian of the genome and an important negative regulator of the cell cycle. Previously, it was unknown whether Aurora B and p53 had mutual regulation during the cell cycle.  A small molecule specific inhibitor of Aurora B, AZD1152, gave us an indication that Aurora B negatively impacted p53 …

Ancient Mitochondrial Dna From Pre-Historic Southeastern Europe: The Presence Of East Eurasian Haplogroups Provides Evidence Of Interactions With South Siberians Across The Central Asian Steppe Belt, Jeremy R. Newton

Masters Theses

Studies of mitochondrial DNA (mtDNA) polymorphism have provided valuable insights for understanding patterns of human migration and interaction. The ability to recover ancient mtDNA sequence data from post-mortem bone and tissue samples allows us to view snapshots of historic gene pools firsthand, provided that great care is taken to prevent sample contamination. In this study, we analyzed the DNA sequence of the first hypervariable segment (HVSI) of the mtDNA control region, as well as a portion of the coding region, in 14 individuals from three collective burials from the Neolithic Dnieper-Donetz culture and three individuals from Bronze Age Kurgan burials, …

The Effects Of Climate Change On Basic Animal Cell Functions, Michelle Fulbright, Andrew Andres

Festival of Communities: UG Symposium (Posters)

Increasing global temperatures during the 21st century may have detrimental effects on basic cell functions within ectothermal animals. This project aims to systematically examine the effects of climate change on secretory cargo localization through the analysis of Rab Proteins found in the model organism Drosophila melanogaster. Rab Proteins play an essential role in vesicular transport within the cell and can be genetically manipulated to monitor the biological consequences of global warming.

The Release Of Calcium In Bacillus Anthracis Pathogenicity Methods, Natiera Magnuson, Manomita Patra Bhowmik, Maria Elena Reynaga, Ernesto Abel-Santos

Festival of Communities: UG Symposium (Posters)

Anthrax infection starts with germination of Bacillus anthracis spores in macrophages. Some bacteria, including B. anthracis, can sporulate in response to environmental stress, such as starvation. During germination, large concentrations of calcium ions are released from the B. anthracis spore. Calcium ions are hydrophilic secondary messengers, and may therefore interfere with detection of the spore by confusing the cell signaling pathways. We investigated calcium release on infected macrophage viability by replacing the calcium stored in B. anthracis spores for other cations via demineralization/remineralization. It was discovered that calcium ions typically out-performed other cations in germination of B. anthracis.

Stationary Phase Mutagenesis In Bacillus Subtilisis Independent Of Genome Replication, Mark Upchurch, Holly Martin, Eduardo Robleto

Festival of Communities: UG Symposium (Posters)

Stationary phase mutagenesis is defined as cellular mechanisms that produce genetic diversity in cells experiencing conditions of stress. These processes are associated with many biological phenomena, including those that produce the formation of cancers in animal cells and other degenerative diseases. Also, these mechanisms are associated with the accumulation of beneficial mutations in bacteria, but follow stochastic processes and are controlled by genetic factors. The current models explaining the generation of stress-induced mutations are predicated on the formation of DNA replication intermediates that are formed during the repair of damaged DNA or during DNA replication and transcription encounters. Here we …

Stem Cell Biology And Strategies For Therapeutic Development In Degenerative Diseases And Cancer, Angel A. Alvarez '98

Doctoral Dissertations

Stem cell biology is an exciting field that will lead to significant advancements in science and medicine. We hypothesize that inducing the expression of stem cell genes, using the embryonic stem cell gene nanog, will reprogram cells and dedifferentiate human mesenchymal stem cells into pluripotent stem cells capable of neural differentiation. The aims of initial studies are as follows:

Aim 1: Demonstrate that forced expression of the embryonic stem cell gene nanog induces changes in human mesenchymal stem cells to an embryonic stem cell-like phenotype.

Aim 2: Demonstrate that induced expression of nanog up-regulates the expression of multiple embryonic stem …

Modulation Of Glutamate-Mediated Neuronal Cell Death By Neurosteroids, Benjamin J. Phelps

Undergraduate Theses and Capstone Projects

Traumatic brain injury (TBI) is a major cause of death and permanent disability in the United States. Approximately 1.7 million cases of TBI are reported annually. After an injury to the head, excessive glutamate, an excitatory neurotransmitter, is released into the extracellular fluid resulting in the excitotoxic death of neuronal tissue. Recent studies have suggested neurosteroids, may serve as an effective means by which to modulate excitotoxicity via the excitatory neurotransmitter alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). Using mixed astrocyte-neuronal cell cultures (14-16 DIV) exposed to increasing concentrations of AMPA as the model for TBI, the experiments examined the effect of the neurosteroids, …

Follicle-Stimulating Hormone Promotes Rank Expression On Human Monocytes, Joseph G. Cannon, Barbara Kraj, Gloria Sloan

School of Medical Diagnostics & Translational Sciences Publications

Elevated serum concentrations of follicle-stimulating hormone (FSH) are associated with diminished bone density in women, beginning years before menopause and the decline in estradiol. We hypothesized that FSH promotes development of myeloid cells toward the bone-resorbing osteoclast phenotype. This was tested by isolating peripheral blood mononuclear cells from nine healthy adults, incubating them in the presence of FSH at three different concentrations spanning the physiological range, and then measuring the expression of receptor activator for NF-κB (RANK, a surface marker for osteoclasts) on CD14+ cells by flow cytometry. In the absence of FSH, 3.3±0.5% of the cells expressed high levels …

Performance Screening Of Chemostat Adapted Recombinant Zymomonas Mobilis Strains, Deirdre M. Beard, Nancy Dowe

STAR Program Research Presentations

Corn stover biomass can be pretreaed and hydrolyzed into soluble sugars to be fermented by microorganisms to ethanol. NREL has developed a recombinant bacteria Zymomonas mobilis 8b that metabolizes both five and six carbon sugars. During pretreatment, toxic inhibitors such as furfural and acetate are produced. NREL has made an attempt to adapt two sub-strains of Z. mobilis 8b to acetate and furfural by using a chemostat method. During the chemostat process, cultures were frozen back in glycerol and saved. In this study, those frozen cultures were revived and analyzed for performance in environments with varying concentrations of furfural and …

Mechanisms Of Yttrium Oxide Toxicity In Hek293 Cells, Sravanthi Bodapati

Theses, Dissertations and Capstones

As a non-metal oxide, yttrium oxide (Y2O3) nanoparticles have numerous applications in chemical synthesis, mechanical polishing and as additives to drugs, cosmetics, varnishes and food. Recent data have suggested that these particles are capable of inducing oxidative stress and cytotoxicity in human endothelial cell lines. To examine the potential mechanisms of yttrium oxide toxicity, human embryonic kidney (HEK293) cells were exposed to 1, 5, 10, 50 and 100 μM of Y2O3 nanoparticles for 12, 24, 36 or 48 hr. We hypothesized that exposure of HEK293 kidney cells to Y2O3 nanoparticles would be associated with increased evidence of intracellular oxidative stress …

Expression Of Genes Involved In A Radiation-Induced Bystander Effect, Hayley Furlong

Conference Papers

The radiation induced bystander effect is relevant to carcinogenesis, it may have significant implications for risk estimation for radiation exposure. Currently the mechanisms and cellular events are the subject of intense investigation, because little is known. It is thought that the radiation induced bystander response is due to a bystander factor secreted in the medium post irradiation. However the biological nature of this factor is currently unknown, but it is thought to be a protein of some sort that may be involved in the apoptosis cascade. Materials and Methods: HaCaT epithelial cells were used in this study and exposed to …

The Role Of The Sparc Acidic Domain And Egf-Like Module In Glioma Migration, Invasion, And Signaling, Heather M. Mcclung

Wayne State University Dissertations

THE ROLE OF THE SPARC ACIDIC DOMAIN AND EGF-LIKE MODULE IN GLIOMA MIGRATION, INVASION, AND SIGNALING

HEATHER M. MCCLUNG

Advisor: Sandra A. Rempel, Ph.D.

Major: Pharmacology

Degree: Doctor of Philosophy

We have previously shown that Secreted Protein Acidic and Rich in Cysteine (SPARC) is upregulated in all astrocytoma grades and increases tumor cell migration and invasion. It is thought that different domains within the protein may regulate SPARC functions, suggesting domain-specific targeting to inhibit invasion. To enhance our understanding of SPARC-mediated invasion, we first confirm, at the protein level, our previous cDNA array results, that SPARC increases expression of the …

Palmitoylation And The Yeast Casein Kinase Yck2, Irene Papanayotou

Wayne State University Dissertations

Palmitoylation is a post-translational lipid modification that allows proteins to interact with membranes. In the yeast Saccharomyces cerevisiae, the casein kinase Yck2 is palmitoylated twice at its two C-terminal palmitoyl-accepting cysteine residues, by the palmitoyl-transferring enzyme Akr1. Once palmitoylated, Yck2 traffics through the well characterized secretory pathway to the plasma membrane where it participates in many cellular functions, including bud morphogenesis, cytokinesis, nutrient sensing, and receptor internalization. While the hydrophilic Yck2 is presumably synthesized on cytosolic ribosomes, it gains access to the membrane system by interaction with the six transmembrane-spanning Golgi-localized Akr1. Since palmitoylation occurs at membranes and the palmitoyl-transferases …

Stress-Induced Proteolysis Of Fkbp10: Mutational Analysis And Functional Implications, Lindsey A. Murphy

Featured Research

Cellular signaling is a complex system of communication that regulates cell function through a variety of molecular messengers. When cell survival is threatened by changes in environment or by malfunction of internal regulatory pathways, signals are initiated to restore homeostasis. Deficient protein processing within the endoplasmic reticulum (ER) causes an accumulation of misfolded proteins and stress signaling. The resulting stress signaling includes both adaptive signals (unfolded protein response) and in cases of severe ER stress apoptotic signals induced via the mitochondria. FKBP10 is a key ER luminal peptidy-prolyl isomerase (rotamase) that mediates protein folding. The production of chaperone proteins and …

The Process Of Autophagy In An In Vitro Model Of Myocardial Ischemia-Reperfusion Injury, Kadija Abounit

Wayne State University Dissertations

Autophagy has been implicated in the pathogenesis of myocardial ischemia-reperfusion (I/R) injury; however, it is not clear whether autophagy is beneficial or detrimental to cell survival. We hypothesized that autophagy is beneficial to cardiomyocytes during I/R and that the paucity of ATP may limit its occurrence. To test this hypothesis, we developed a model of ischemia (hypoxia) involving exposure of HL-1 murine atrial cardiomyocytes to two concentrations of oxygen (0.5% and 2.0%) and 2-deoxyglucose.

Hypoxia, irrespective of the oxygen concentration, caused a dramatic drop in cellular ATP and an increase in the phosphorylation of AMPK (an indication of energy starvation),. …

Analysis Of Biological Features Associated With Meiotic Recombination Hot And Cold Spots In Saccharomyces Cerevisiae, Loren Hansen, Nak-Kyeong Kim, Leonardo Mariño-Ramírez, David Landsman

Mathematics & Statistics Faculty Publications

Meiotic recombination is not distributed uniformly throughout the genome. There are regions of high and low recombination rates called hot and cold spots, respectively. The recombination rate parallels the frequency of DNA double-strand breaks (DSBs) that initiate meiotic recombination. The aim is to identify biological features associated with DSB frequency. We constructed vectors representing various chromatin and sequence-based features for 1179 DSB hot spots and 1028 DSB cold spots. Using a feature selection approach, we have identified five features that distinguish hot from cold spots in Saccharomyces cerevisiae with high accuracy, namely the histone marks H3K4me3, H3K14ac, H3K36me3, and H3K79me3; …

Disorder Predictors Also Predict Backbone Dynamics For A Family Of Disordered Proteins, Gary W. Daughdrill, Wade M. Borcherds, Hongwei Wu

Molecular Biosciences Faculty Publications

Several algorithms have been developed that use amino acid sequences to predict whether or not a protein or a region of a protein is disordered. These algorithms make accurate predictions for disordered regions that are 30 amino acids or longer, but it is unclear whether the predictions can be directly related to the backbone dynamics of individual amino acid residues. The nuclear Overhauser effect between the amide nitrogen and hydrogen (NHNOE) provides an unambiguous measure of backbone dynamics at single residue resolution and is an excellent tool for characterizing the dynamic behavior of disordered proteins. In this report, we show …

An Apoptosis Targeted Stimulus With Nanosecond Pulsed Electric Fields (Nspefs) In E4 Squamous Cell Carcinoma, Wei Ren, Stephen J. Beebe

Bioelectrics Publications

Stimuli directed towards activation of apoptosis mechanisms are an attractive approach to eliminate evasion of apoptosis, a ubiquitous cancer hallmark. In these in vitro studies, kinetics and electric field thresholds for several apoptosis characteristics are defined in E4 squamous carcinoma cells (SCC) exposed to ten 300 ns pulses with increasing electric fields. Cell death was [95% at the highest electric field and coincident with phosphatidylserine externalization, caspase and calpain activation in the presence and absence of cytochrome c release, decreases in Bid and mitochondria membrane potential (Δψm) without apparent changes reactive oxygen species levels or in Bcl2 and Bclxl levels. …

Rho Kinase Regulates Basement Membrane Dynamics To Coordinate Salivary Gland Branching Morphogenesis And Tissue Organization, William Patrick Daley

Legacy Theses & Dissertations (2009 - 2024)

Branching morphogenesis is a developmental mechanism utilized by many organs, including the salivary gland, lung, kidney, and mammary gland, to increase the epithelial surface area for secretion or absorption. The embryonic submandibular salivary gland (SMG) is a classic model for studying tissue morphogenesis in three dimensions ex vivo. Salivary gland development requires distinct but overlapping processes: morphogenesis, the actual physical rearrangement of cells into complex three dimensional structures, and cytodifferentiation, the process by which these cells begin to take on their own specialized function. Polarization, or the organization of cells into a cohesive tissue structure, also occurs concurrently during organ …