Biochemistry Commons^™

Regulation Of Gene Expression By Rna Binding Proteins And Micrornas, Kyle Cottrell

Arts & Sciences Electronic Theses and Dissertations

Regulation of gene expression is essential to life. Post-transcriptional regulation of gene expression is a complex process with many inputs that lead to changes in localization, translation and stability of mRNAs. The translation and stability of many mRNAs is regulated by cis-elements, such as mRNA-structure or codon optimality; and by trans-acting factors such as RBPs and miRNAs. Here I report on the complex interactions between RBPs, miRNAs and characteristics of their target mRNAs in respect to effects on translation and RNA stability.

Using a reporter based approach we studied modulation of microRNA-mediated repression by various mRNA characteristics. We observed the …

Metabolic Reprogramming Of Pancreatic Ductal Adenocarcinoma Cells In Response To Chronic Low Ph Stress, Jaime Abrego

Theses & Dissertations

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of all cancers with a 5-year survival rate of only 8.2%. This is because PDAC is diagnosed in its advanced stages and is characterized by radio and chemotherapy resistance. Aggressiveness of PDAC tumors is attributed to its high metabolic phenotype, which is characterized by increased glycolysis rate and lactate secretion, while oxidative metabolism is reduced. These metabolic features are required to fulfill the biosynthetic demands of proliferating PDAC cells. However, this increase in metabolic activity results in acidification of the extracellular space because the dense fibrotic stroma of PDAC tumors limits …

Determination Of The Effects Of Different Maillard Reaction Products On The Taxonomic Composition Of The Gut Microbiota, Nesreen Hamdan Aljahdali

Graduate Theses and Dissertations

The Maillard Reaction (MR) is a non-enzymatic chemical reaction which results in linkage between the amino group of amino acids and the carbonyl group of reduced sugars. This reaction generates Maillard reaction products (MRPs) which are not present naturally in foods, and are responsible for a range of colors, odors, flavors, and other sensory properties. Conflicting reports of MRPs impacts on human health are probably due to the fact that bioconversion of these digestible molecules by the gut microbiota has been marginally taken into account. This study aimed to determine the effects of different MRPs on rodent’s gut microbiota through16S …

Role Of Cannabinoid Receptor Type 2 (Cb2) In Late Stage Atherosclerosis, Makenzie Fulmer

Electronic Theses and Dissertations

Atherosclerosis is a chronic inflammatory disorder of medium and large vessels. Immune signaling and dyslipidemia are two of several processes which influence lesion development in atherosclerosis. Cannabinoids, such as those found in marijuana, exert their effects through two cannabinoid receptors, CB1 and CB2. Recent studies using CB2 knockout mice and CB2-selective ligands have shed light on a protective role of CB2 in early stages of atherosclerosis. However, the role of CB2 in advanced stages of atherosclerosis remains unclear. To determine if CB2 plays a role in advanced atherosclerotic lesion composition and progression, we investigated the effects of systemic CB2 gene …

Insights Into The Therapeutic Potential Of Salt Inducible Kinase 1: A Novel Mechanism Of Metabolic Control, Randi Fitzgibbon

Dissertations & Theses (Open Access)

Salt inducible kinase 1 (SIK1) has been considered a stress-inducible kinase since it was first cloned in 1999. Continued efforts since this time have been dedicated to characterizing the structure and function of SIK1. Such research has laid the ground work for our understanding of SIK1 action and regulation in tissue and stimuli dependent manners. The fundamental findings of this dissertation continue in this tradition and include investigations of SIK1 regulatory mechanisms in skeletal muscle cells, the cellular and physiological effects of SIK1 loss of function in vitro and in vivo, and intracellular metabolic and mitochondrial regulation by this …

Type Ix Secretion System : Characterization Of An Effector Protein And An Insight Into The Role Of C-Terminal Domain Dimeration In Outer Membrane Translocation., Lahari Koneru

Electronic Theses and Dissertations

Porphyromonas gingivalis and Tannerella forsythia are two of the primary pathogens that are associated in the etiology and progression of chronic periodontitis. In T. forsythia, KLIKK proteases are the recently identified group of proteolytic enzymes that are secreted through Type IX secretion system (T9SS). Among, these KLIKK proteases a synergistic relationship was observed between karilysin and mirolysin in invading the host complement system for the survival of the bacteria. Since, karilysin has been already characterized, in this study we propose to study about mirolysin through structural, biochemical and biological characterization. The obtained results from the experiments has shown the …

Mechanism Elucidation And Inhibitor Discovery Against Serine And Metallo-Beta-Lactamases Involved In Bacterial Antibiotic Resistance, Orville A. Pemberton

USF Tampa Graduate Theses and Dissertations

The emergence and proliferation of Gram-negative bacteria expressing β-lactamases is a significant threat to human health. β-Lactamases are enzymes that degrade the β-lactam antibiotics (e.g., penicillins, cephalosporins, monobactams, and carbapenems) that we use to treat a diverse range of bacterial infections. Specifically, β-lactamases catalyze a hydrolysis reaction where the β-lactam ring common to all β-lactam antibiotics and responsible for their antibacterial activity, is opened, leaving an inactive drug. There are two groups of β-lactamases: serine enzymes that use an active site serine residue for β-lactam hydrolysis and metalloenzymes that use either one or two zinc ions for catalysis. Serine enzymes …

Dissecting Molecular Pathways That Ensure Proper Chromosome Segregation And Cell Division, Anna Ye

Doctoral Dissertations

Equal segregation of the genome is a prerequisite for cell survival. During cell division the duplicated DNA is compacted into chromosomes and a multi-protein macrostructure, known as the kinetochore (Kt), is assembled on each copy of compacted DNA. Simultaneously, the mitotic spindle, which is made up of microtubules (MTs), is built to facilitate the equal distribution of the chromosomes between the resulting daughter cells. Kinetochores mediate the interaction between the MTs and the chromosomes, properly positioning them for segregation. To ensure that the DNA is equally divided in every cell division, cells have built a surveillance system to detect any …

Regulated Proteolysis Of Dnaa Coordinates Cell Growth With Stress Signals In Caulobacter Crescentus, Jing Liu

Doctoral Dissertations

DNA replication is an essential process in all domains of life. Replication must be precisely regulated, especially at the step of initiation. In bacteria, the replication initiator DnaA is regulated by multiple post-translational regulations to ensure timely replication. Caulobacter crescentus has the most strict replication regulation that DNA only replicates once per cell cycle, and proteolysis of DnaA identified in this species is the only irreversible way to inhibit DnaA, suggesting it might be pivotal to restricting DNA replication. However, the responsible protease(s) and mechanism for its degradation remain unclear since its first discovery in 2005. In this thesis, I …

Pore Forming Protein Assembly And The Use In Nanopore Sensing: A Study On E. Coli Proteins Clya And Ompg, Monifa Fahie

Doctoral Dissertations

Pore forming proteins are typically the proteins that form channels in membranes. They have several roles ranging from molecule transport to triggering the death of a cell. This work focuses on two E. coli pore forming proteins that have vastly differing roles in nature. Outer membrane protein G (OmpG) is an innocuous β-barrel porin while Cytolysin A (ClyA) is an α-helical pore forming toxin. For OmpG we probed its potential to be a nanopore sensor for protein detection and quantification. A small high affinity ligand, biotin, was covalently attached to loop 6 of OmpG and used to capture biotin-binding proteins. …

Pharmacological Antagonism And The Olfactory Code, Mihwa Na

Dissertations, Theses, and Capstone Projects

Mammals can detect and discriminate uncountable odors through their odorant receptors. To accommodate the countless and diverse odors, exceptionally large numbers of odorant receptor (OR) genes are expressed in mammals. In addition, the mammals utilize a combinatorial code, where an odorant molecule can activate multiple ORs; an OR also responds to a set of multiple odorants. In nature, an odor is often a complex mixture of multiple odorant molecules. The combination of the ORs activated by each constituent generates the unique olfactory code for the particular odor.

Some odorants can antagonize select ORs, as discussed in Chapter 1. An antagonist …

An Investigation Of The Ck2-Dependent Phosphoproteome Using Inhibitor Refractory Ck2-Alpha, Edward Cruise

Electronic Thesis and Dissertation Repository

Protein kinase CK2 is a constitutively active serine/threonine kinase that is overexpressed in several human cancers, and by virtue of the vast number of putative substrates in the phosphoproteome, is implicated in the regulation of numerous cellular processes. Consequently, CK2 is an emerging therapeutic target with many CK2 inhibitors having been developed. An example of one such inhibitor is the clinical stage compound CX-4945. Although highly selective for CK2, the ATP competitive CX-4945 has demonstrated affinity for other kinases. Unique features of the catalytic pocket of CK2 have allowed for the development of inhibitor refractory mutants, which have since been …

Mutagenesis Of Human Alpha-Galactosidase A For The Treatment Of Fabry Disease, Erin Stokes

Dissertations, Theses, and Capstone Projects

Fabry disease is an X-linked lysosomal storage disorder caused by the deficiency of the enzyme, α-galactosidase A, which results in the accumulation of the lipid substrate. This accumulation results in obstruction of blood flow in patients and early demise at approximately 40-60 years of age. There is currently only one FDA approved treatment (Fabrazyme) classified as an enzyme replacement therapy. However, approximately 88% of patients experience a severe immune response that, rarely, can be fatal and is a huge cost burden at average $250,000 a year per patient. The structure of α-galactosidase A has been previously determined to be a …

Insight Into The Interaction Between The Peroxisome Proliferator-Activated Receptor Gamma (Pparγ) And Adipocyte Fatty Acid-Binding Protein (A-Fabp), Qian Wang

Dissertations, Theses, and Capstone Projects

The Adipocyte Fatty Acid-Binding Protein (AFABP) is mainly expressed in fat cells. It can bind fatty acids and other lipophilic substances such as eicosanoids and retinoids. The peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor protein that requires ligand binding to regulate the specific gene transcription. PPARγ is expressed at extremely high levels in adipose tissue, macrophages, and the large intestine, where it controls lipid adipogenesis and energy conversion. Moreover, it has been found that AFABP and PPARγ can form a complex in vivo. It is proposed that AFABP carries the ligand and enters into the nucleus where it …

Molecular Mechanisms Of C-Terminal Eps15 Homology Domain Containing (Ehd) Protein Function, Kriti Bahl

Theses & Dissertations

Endocytic trafficking is not only an essential process for the maintenance of cellular homeostasis but also plays a vital role in regulating diverse cellular processes such as signaling, migration and cell division. The C-terminal Eps 15 Homology Domain proteins (EHD1-4) play pivotal roles in regulating distinct steps of endocytic trafficking. Among the EHDs, EHD2 is disparate both in terms of sequence homology (70%) and its subcellular localization at the caveolae. The crystal structure of EHD2 has been solved and it contains an unstructured loop consisting of two proline-phenylalanine (PF) motifs: KPFRKLNPF. However, the other paralogs EHD1, …

Mechanisms And Regulation Of Resection In Dna Damage Response, Sharad C. Paudyal

Arts & Sciences Electronic Theses and Dissertations

Deoxyribonucleic acid (DNA) encodes genetic information essential for cell survival and function. However, it is constantly under assault from endogenous and exogenous damaging agents that not only threaten our own survival but also affect the faithful transmission of genetic information to our offspring. Double-strand breaks (DSBs) are one of the most hazardous forms of DNA damage, which if unrepaired or improperly repaired could lead to plethora of systemic human diseases including cancer. To deal with this problem, cells have evolved with a mechanism called DNA damage response (DDR) to detect, signal, and repair the breaks by inducing multiple cellular events. …

The Structural And Functional Properties Of A Double Mutant Of Human Acidic Fibroblast Growth Factor (Hfgf-1), Arwa Mohammed Alghanmi

Graduate Theses and Dissertations

Human acidic Fibroblast Growth Factor 1 (FGF-1), a member of the FGF superfamily, is a potent mitogen and heparin-binding protein involved in a broad spectrum of biological processes, including angiogenesis, cell proliferation, and wound healing. Design of hFGF-1 with an increased thermal stability and an enhanced cell proliferation activity is highly desired for wound healing applications. Herein, we have designed the variant of FGF-1 by substituting two important amino residues in the heparin-binding pocket. The variant was overexpressed in Escherichia coli and was successfully purified to homogeneity using an affinity chromatographic procedure. Far-UV circular dichroism spectroscopic analysis showed that the …

Investigating The Role Of Prmt1 And Arginine Methylation Of Hsp70 In Human Pancreatic Cancer, Liang Wang

Dissertations & Theses (Open Access)

Protein arginine methyltransferase 1 (PRMT1) is the major arginine methyltransferase, which catalyzes the addition of one or two methyl groups to the arginine residues of its substrate proteins. The best-known substrate for PRMT1 is histone, while more and more non-histone proteins are now found to be methylated by PRMT1. Dysregulation of PRMT1 is reported in several human cancer types. However, its biological roles in human pancreatic cancer initiation and development are still unclear. In the first part of this study, I found that the expression level of PRMT1 was elevated in both human and mouse pancreatic cancer tissues in immunohistochemistry …

Characterization Of A Tuberous Sclerosis Complex 2 Variant And Its Interaction Involving The Ras-Related Protein Rheb, Nosaiba Shokr

Graduate Theses and Dissertations

Structure-function relationships of any complex underlie the molecular details of the biological interactions. Rheb, Ras Homology Enriched in Brain, is a Ras-related protein, and it is genetically identified as a molecular switch. Rheb is regulated by cycling between the biologically active GTP and inactive GDP-bound forms. This regulation is partially controlled by an interaction with Tuberous Sclerosis Complex2 (TSC2), a GTPase activating protein (GAP). Upon interaction, TSC2 stimulates Rheb GTP hydrolysis and diminishes the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway is involved in proteins synthesis, cell cycle, and signaling. Mutation in TSC2 causes abnormal activation of Rheb …

Molecular And Biochemical Studies Of Several Novel Estrogen Receptor Alpha-Interacting Proteins In Breast Cancer Cells, Ahmed Edan Dhamad

Graduate Theses and Dissertations

Breast cancer is the second leading cause of cancer-related death in women, and approximately 70% of incidences are estrogen receptor (ER)-positive breast cancer. ERα and its interacting proteins play a key role in the development and progression of breast cancer. However, how ERα regulates its target gene expression and hence cell proliferation is not fully understood. To enhance our understanding of the molecular mechanism by which ERα regulates gene expression, we used a quantitative proteomic method to identify cellular proteins that interact with ERα. The first group of proteins that were identified to associate with ERα are heat shock proteins …

The Key Question In Symbiotic Nitrogen Fixation: How Does Host Maintain A Bacterial Symbiont?, Onur Oztas

Doctoral Dissertations

The fact that plants cannot use nitrogen in the gaseous form makes them dependent on the levels of usable nitrogen forms in the soil. Legumes overcome nitrogen limitation by entering a symbiotic association with rhizobia, soil bacteria that convert atmospheric nitrogen into usable ammonia. In root nodules, bacteria are internalized by host plant cells inside an intracellular compartment called the symbiosome where they morphologically differentiate into nitrogen-fixing forms by symbiosome-secreted host proteins. In this project, I explained the host proteins required to maintain bacterial symbionts and described their delivery to the symbiosome. I showed that the SYNTAXIN 132 (SYP132) gene …

Adaptors At Work: Regulation Of Bacterial Proteolysis By Adaptor Hierarchies, Kamal Joshi

Doctoral Dissertations

Regulated protein degradation is essential for all life. Bacteria use energy-dependent proteases to regulate protein degradation. Recognition of a substrate is enabled by the inherent specificity of the protease and by the use of adaptor proteins that widen the spectrum of recognized substrates. In Caulobacter crescentus, the timed destruction of many regulators including CtrA by the ClpXP protease drives cell cycle progression. Although, in a test tube, ClpXP can degrade CtrA by itself and does not need any helping factors, additional factors such as CpdR, RcdA and PopA are required in vivo. Understanding how these factors modulate protease …

Rational Drug Design Directed At Blocking The Initial Signaling Events In Lipopolysaccharide-Induced Sepsis., Christopher A. Tipton

Theses

Systemic Inflammatory Response Syndrome (SIRS) is classified as an immune system response to an infectious state. If left untreated, SIRS leads to sepsis, septic shock, end-organ dysfunction, and death. As a patient progresses through these stages, associations of acute respiratory distress, disseminated intravascular coagulation, and acute renal failure persist, resulting in millions of deaths annually. Lipopolysaccharide (LPS), a bacterial endotoxin, is released into the blood stream, triggering SIRS. LPS is found in the outer cell-wall of Gram-negative bacteria and is responsible for initiation of a devastating cytokine storm. One of the regions of LPS, lipid A, is a polyacylated glucosamine …

Characterization Of Genes Involved In Phycobiliprotein Biosynthesis In Fremyella Diplosiphon And Thermosynechococcus Elongatus, Christina M. Kronfel

University of New Orleans Theses and Dissertations

Cyanobacteria are photosynthetic organisms that efficiently capture light by utilizing the light-harvesting complexes called phycobilisomes. In many cyanobacteria, phycobilisomes are composed of an allophycocyanin core with phycocyanin and phycoerythrin (PE) rods radiating from the core. These phycobiliproteins have multiple bilin chromophores, such as phycoerythrobilin (PEB), covalently attached to specific cysteine (Cys) residues for efficient photosynthetic light capture. Chromophore ligation on phycobiliprotein subunits occurs through bilin lyase catalyzed reactions.

This study mainly focuses on characterizing the roles of enzymes that are involved in the biosynthetic pathway of the phycobiliproteins within two cyanobacteria Thermosynechococcus elongatus and Fremyella diplosiphon. A combination of molecular …

The Rpl13a Snorna U33 Forms Novel Snornps During Lipotoxicity, Miquia Sherree Henderson

Arts & Sciences Electronic Theses and Dissertations

Lipid overload contributes to the pathogenesis of diabetic complications, causing tissue damage and cell death in a number of organ systems. This process is termed lipotoxicity. Animal and cell culture studies have demonstrated that oxidative stress and endoplasmic reticulum stress are major pathways engaged in the lipotoxic response. However, the molecular mechanisms of lipotoxicity are not well understood. A genetic screen revealed that small nucleolar RNAs (snoRNAs) encoded in the introns of the Rpl13a locus are critical for cell death in response to lipotoxicity. Initial studies have suggested that the Rpl13a snoRNAs function in this pathway through non-canonical modes of …

B7h6: A Cancer Biomarker For The Development Of Novel Immunotherapy Approaches, Mariana Phillips

Seton Hall University Dissertations and Theses (ETDs)

Cancer-based immunotherapy has led the evolution of biologics that can stimulate immune responses towards tumor eradication. The synthesis of small to intermediate size molecules with the targeting and effector functions of mAb may represent a novel class of immunotherapeutics that may overcome the limitations of their biological counterparts.Towards this objective, B7H6 has been identified as a protein ligand localized on the cell surface of transformed tumor cells. B7H6 binds specifically to the activating receptor NKp30, constitutively expressed on all resting and active NK cells. Upon ligand:receptor binding, B7H6 triggers NK cell activation and release of chemokines and pro-inflammatory cytokines such …

Structural, Biophysical, And Functional Studies Of Trem2 In Neurodegenerative Disease, Daniel L. Kober

Arts & Sciences Electronic Theses and Dissertations

Alzheimer's disease (AD) and other neurodegenerative diseases present a large and growing challenge to global health. The immune system, particularly the innate immune system, is increasingly recognized as having a major role in these pathologies. The innate immune system is responsible to contain disease and promote healing. However, immune misregulation exacerbates disease. The innate immunomodulatory receptor Triggering receptor expressed on myeloid cells-2 (TREM2) is expressed on myeloid cells such as dendritic cells, macrophages, and in the brain, on microglia. TREM2 is a single-pass transmembrane receptor with an extracellular Ig domain that mediates ligand binding. This protein regulates inflammation in vitro …

Mechanisms Of G Protein Regulation By Rgs Proteins And Small Molecule Inhibitors, Stanley Michinobu Kanai

Arts & Sciences Electronic Theses and Dissertations

G protein coupled receptors transduce diverse extracellular signals like hormones, neurotransmitters, and photons to specific cellular responses through heterotrimeric G proteins. G proteins activate numerous effectors and signal transduction pathways, and therefore the regulation of G proteins is crucial for faithful propagation of specific cellular and physiological responses. A better understanding of the mechanisms that regulate G proteins should provide new insight into signaling pathways that govern healthy and disease states, and also provide opportunities for discovery of novel therapeutic targets.Regulator of G protein signaling (RGS) proteins are crucial regulators of G proteins, for they control amplitude and duration of …

Cloning, Purification, And Biochemical Characterization Of Human Prolyl Endopeptidase, Travis K. Moore

Electronic Theses and Dissertations

Eurygaster integriceps Puton, common name sunn Pest, is one of the primary sources of wheat crop wastes in North Africa, Middle East, and Eastern Europe. It feeds by injecting the wheat grain with an enzyme characterized as prolyl endoprotease (spPEP) that breaks down Gluten, the wheat’s main constitutive protein necessary for bread production (Darkoh et al., 2010). Previously, it has been shown that peptides isolated from Lactobacillus hydrolysates of caseins in bovine milk are able to inhibit mammalian PEP in colon cells, as well as bacterial PEP (Juillerat-Jeanneret et al., 2010). While recombinant versions of these peptides are also potential …

Altered Na, K- Atpase Isoform Expression In Artemia Franciscana In Response To Hypersaline Environments, Jessica Drenth

Theses and Dissertations

The Na,K-ATPase (NKA) is an essential membrane pump that helps to establish cell ion gradients, and regulate intracellular salt in many organisms. One such species, Artemia franciscana (brine shrimp), extreme halophiles which live in hypersaline environments, expresses 2 distinct α-catalytic subunits of the NKA. One of these subunits, α2-(KK), has two key lysine substitutions located within the cation binding sites. Prior work has demonstrated this specific subunit may be directly involved in brine shrimp adaptation to their extreme environments. However, the precise molecular and physiological effects of α2-(KK) have not been entirely elucidated. I determined through immunohistochemistry that my initial …