Biochemistry, Biophysics, and Structural Biology Commons^™

Cardiac Calsequestrin Phosphorylation And Trafficking In The Mammalian Cardiomyocyte, Timothy Mcfarland

Wayne State University Dissertations

Cardiac CSQ (CSQ2) is a multifaceted protein, capable of binding significant quantities of Ca2+ and altering ryanodine receptor activity at the junctional sarcoplasmic reticulum (SR). Little is known about the trafficking of CSQ2 from its unknown site of biosynthesis, which appears to be of importance as its structure changes in a trafficking-dependent manner in various types of heart failure. Through the use of multiple antibodies specific to classic rough ER markers, and with the creation of CSQ-DsRed tetramer fusion protein, we were able to establish a juxtanuclear localization of rough ER in cardiomyocytes. Using fluorescence confocal microscopy, the translocon complex …

Artificial And Natural Nucleic Acid Self Assembling Systems, Marcus Wood

Wayne State University Dissertations

Nucleic acids are good candidates for nanomachine construction. They participate in all the processes of life, and so can function as structural building blocks and dynamic catalysts. However, to use nucleic acids as nanomachines, a better understanding of their material properties, how to design structures using them, and their dynamics is needed. We have tried to address these issues, in a small way, with nucleic acid force field development, an attempt at nanostructural design and synthesis using DNA, and a study of the RNA/protein regulatory dynamics of the tryptophan regulatory attenuation protein.

Hedgehog Signaling: A Potential Therapeutic Target For Non-Small Cell Lung Cancer, Ma'in Yehya Maitah

Wayne State University Dissertations

The American Cancer Society estimated that 222,520 Americans were diagnosed with lung cancer and 157,300 died of lung cancer in 2010 (Jemal et al. 2009, 225-249;Jemal et al. 2011, 69-90). The clinical outcome of patients diagnosed with non-small cell lung cancer (NSCLC), the major lung cancer sub-types, is very poor, which calls for innovative research for finding novel therapeutic targets and agents for better treatment outcome.

Emerging evidences have suggested that a phenomenon called Epithelial-to-Mesenchymal Transition (EMT), which shares similar molecular characteristics with cancer stem-like cells, contributes to lung cancer treatment failure. In view of the fact that EMT process …

Mechanical Forces And Tumor Cells: Insight Into The Biophysical Aspects Of Cancer Progression, Indrajyoti Indra

Wayne State University Dissertations

Mechanical forces play an important role in the regulation of cellular behavior and physiological processes including adhesion, migration, proliferation, tissue repair, embryogenesis and development. In addition, a number of diseases including cancer, have been linked to changes in cellular and extracellular mechanical properties. However, whether a correlation exists between the progression of cancer towards metastasis and mechanical factors has not been clearly defined. Additionally, how a cell responds to changes in extracellular mechanical cues as it gains metastatic abilities is poorly understood. To address these questions, we have utilized a panel of murine breast cancer cell lines with progressive metastatic. …

Exploring Potential Drug Target Sites In The Ribosome Using Cisplatin And Its Analogues, Keshab Rijal

Wayne State University Dissertations

Cis-diamminodichloridoplatinum (II), cisplatin, is an antitumor drug that has been used to treat several types of cancers. The reaction of cisplatin with DNA has been studied and discussed extensively in the literature; however, the effects of cisplatin on RNA function are poorly understood. In this thesis, two aspects of cisplatin, its preferred sites of interaction with RNA and its use as a chemical probe to gain accessibility information, were explored.

To understand the site-selectivity of cisplatin with RNA, model RNA constructs and full-length 16S rRNA were employed. The binding studies revealed a cisplatin preference for guanosine-rich sequences. Primer extensions in …

Molecular Details Of The Mitochondrial Iron Sulfur Cluster Assembly Pathway, Swati Rawat

Wayne State University Dissertations

MOLECULAR DETAILS OF THE MITOCHONDRIAL IRON SULFUR CLUSTER ASSEMBLY PATHWAY

Iron-sulfur clusters are an important class of prosthetic group involved in electron transfer, enzyme catalysis, and regulation of gene expression. Their biosynthesis requires complex machinery located within the mitochondrion since free iron and sulfide are extremely toxic to the cell. Defects in this pathway results in several diseases such as Friedreich's Ataxia (FRDA), Sideroblastic Anemia and ISCU Myopathy. Therefore molecular details of the biogenesis pathway will provide deep insight in the pathway and treatment options for these diseases. FRDA is caused by deficiency of a single protein called as `Frataxin'. …

Characterization Of Splicing Mechanisms By Single-Molecule Fluorescence, Krishanthi Sanjeewani Karunatilaka

Wayne State University Dissertations

Group II introns rank amongst the largest self-splicing ribozymes found in bacteria and organellar genomes of various eukaryotes. Despite the diversity in primary sequences, group II introns posses highly conserved secondary structures consisting of six domains (D1-D6). To perform its function, the large multidomain group II intron RNA must adopt the correctly folded structure. As a result, in vitro splicing of these introns requires high ionic strength and elevated temperatures. In vivo, this process is mainly assisted by protein cofactors. However, the exact mechanism of protein-mediated splicing of group II intron RNA is still not known.

In order to …

Effects Of Dietary Fat Saturation On Lipoprotein Metabolism In Rodents And Humans, Deepinder Kaur

Wayne State University Dissertations

Consumption of trans-fatty acids (tFA) and saturated fatty acids (SFA) have been associated with higher incidence of coronary heart disease. Experimental and observational data suggests that consumption of PHVO containing tFA, like SFA leads to increased total cholesterol and LDL-cholesterol (LDL-C) but compared to tFA, SFA raises HDL-cholesterol (HDL-C). An attempt to eliminate PHVO from the food supply has resulted in the need to find alternatives which despite their higher dietary fat saturation as compared to naturally occurring vegetable oils, may be preferable to PHVO. However, amongst SFA, the effects on plasma lipoproteins are variable. Thus, we hypothesized that specific …

Identification Of The Role Of The Sal Locus In Streptococcus Pyogenes Virulence During Host-Pathogen Interactions, Phanramphoei Namprachan-Frantz

Wayne State University Dissertations

The pathogenesis of Streptococcus pyogenes is due to its ability to overcome and adapt to the harsh environment created by the host immune response. The focus of this project was the SalKR two-component regulatory system, which facilitates bacterial adaptation by responding to environmental signals during host pathogen-interactions. The first goal of this project was to determine a role in virulence for the SalKR regulatory system. The complete deletion of the salKR genes in the wild type S. pyogenes strain HSC5 produced a highly attenuated mutant in a Zebrafish infection model. The ΔsalKR mutant appeared to lose the ability to survive …

Laser-Assisted Single-Molecule Refolding, Rui Zhao

Wayne State University Dissertations

Non-coding RNAs must fold into precise secondary and tertiary structures in order to perform the biological functions. Due to the flexibility of RNA, the RNA folding energy landscape can be rugged and full of local minimum (kinetic trap). To provide a means to study kinetically trapped RNAs, we have developed a new technique combining single-molecule FRET detection with laser induced temperature jump. We have calibrated the magnitude of the temperature jump with 1˚C accuracy using gold micro-size sensor. The accuracy of temperature calibration was confirmed by close agreement between single-molecule and bulk DNA duplex melting experiments.

HIV 1 DIS RNAs …

A Novel In Vivo Protein Refolding Technique, Yuefei Huang

Wayne State University Dissertations

Proteins perform their functions in their native folded states and misfolding of proteins may cause severe diseases, including Alzheimer's disease, Parkinson's disease, prion disease and diabetes. Understanding protein folding is important for us to engineer proteins to treat these diseases. For protein therapeutics, large quantities of properly folded and functional proteins are required. The current technology produces recombinant proteins using either eukaryotic or prokaryotic expression system, both of them have major problems that prevent production of large quantities of properly folded and functional human proteins for protein therapeutics.

Although the eukaryotic cells have comprehensive folding machinery that contains chaperones and …

Destruction Of Biological Tetrapyrrole Macrocycles By Hypochlorous Acid And Its Scavenging By Lycopene, Dhiman Maitra

Wayne State University Dissertations

Hypochlorous acid (HOCl) is a potent oxidant generated by the hemoprotein myeloperoxidase. Although HOCl plays an important role in the innate immune response,sustained high levels of HOCl has been implicated to play a harmful role. In several pathological conditions such as atherosclerosis, endometriosis and sickle cell disease where HOCl is elevated there are reports of significant free iron accumulation. Free iron is toxic since it can lead to the generation of other secondary free radicals such as hydroxyl radical by Fenton reaction. The exact source and mechanism by which the free iron is generated is not clearly understood. This work …

Rox1 Function In Dosage Compensation: Structural / Functional Analysis Of A Non-Coding Rna, Ying Kong

Wayne State University Dissertations

roX1 is a long non-coding RNA involved in the chromosome-wide gene regulation that occurs during dosage compensation in Drosophila. Dosage compensation in Drosophila melanogaster occurs by a global two-fold increase of transcription from the single male X chromosome. This essential process compensates for X chromosome monosomy. The male-specific lethal (MSL) complex, containing five proteins, localizes to the male X chromosome and alters chromatin to modify gene expression. roX1 and roX2 RNAs are redundant components of MSL complex that are required for its exclusive X-localization. Recent studies in our lab have revealed a second role of roX RNAs in heterochromatic gene …

Human Trophoblast Survival And Invasion In The Developing Placenta: Autocrine Regulation By Hbegf, Philip Jessmon

Wayne State University Dissertations

HBEGF is a multifunctional protein in early pregnancy that induces cytotrophoblast (CTB) cell differentiation to an invasive phenotype, protects against apoptosis, and is involved in an autocrine signaling mechanism that leads to its own protein synthesis. CTBs exist in a low O₂ environment during the first 10 weeks of implantation, during which they invade the decidualized uterine stroma. Inhibitors of intracellular signaling pathways demonstrated that at 20% O₂ HBEGF induces an increase in cell migration through the ERK, MAPK14, JNK, or PIK3 pathways downstream of signaling through its ERBB receptors. Also downstream of these four pathways, HBEGF induces …

Method Development And Applications To Screening And Characterization Of Rrna-Targeting Small Molecules, Papa Nii Asare-Okai

Wayne State University Dissertations

A series of single ring aminoglycoside analogues was tested for binding to a model RNA representing the A site using electrospray ionization mass spectrometry (ESI-MS). Several of the synthetic analogues with low molecular weights were found to bind to the RNA with affinities comparable to the parental aminoglycoside neamine, with apparent dissociation constants in the low micromolar range. Salt dependence of the affinity constants for the single ring analogues revealed a predominantly electrostatic binding mode. Footprinting experiments revealed that one of the compounds (DHR23) has a similar binding site as the antibiotic paromomycin. DMS chemical probing results also suggest that …

Nmr Solution Structures Of Two Hairpins Of E. Coli 16s Rrna: The Effects Of Mutations And Chemical Modifications On Structure And Function Of Rrna, Yu Liu

Wayne State University Dissertations

The structures of two functional mutants, the UC (G690U, U697C) and the QM mutants (G690A, G693C, A695C, U697A) of the 690 hairpin of E. coli 16S ribosomal RNA were determined by NMR. The UC mutant and the QM mutant with high biological function are able to fold into structures that are isomorphous with the wild-type 690 hairpin sequence. The structural comparisons among the functional mutants and the wild-type provides structural validation for previously identified specific functional groups that are crucial for maintaining function of the 690 hairpin. The key groups for maintaining the structure and function of the 690 loop …

Crystallographic, Molecular Dynamics, And Enzymatic Studies Of Multi-Drug Resistant Hiv-1 Protease And Implications For Structure Based Drug Design (Project 1); Crystallographic Studies Of Human Myelin Protein Zero (Project 2), Zhigang Liu

Wayne State University Dissertations

Under drug selection pressure, emerging mutations render HIV-1 protease drug resistance, leading to the therapy failure in anti-HIV treatment.Tthe multidrug-resistant 769 (MDR) HIV-1 protease (resistant mutations at residues 10, 36, 46, 54, 62, 63, 71, 82, 84, 90) is selected for the present study to understand drug resistance issue.

Ten additional mutations are introduced to MDR769 HIV-1 protease to study the structural influences brought by these mutations. We get crystal structures of four variants (I10V, A82F, A82S and A82T) of MDR769 HIV-1 protease. All these mutations fail to further open the flaps and expand the active site cavity of MDR769 …

Amphiregulin (Areg) And Epidermal Growth Factor (Egf): Disparate In Egfr Signaling And Trafficking, Andrea Jacqueline Baillo

Wayne State University Dissertations

We have previously shown that SUM-149 human breast cancer cells require an AREG/EGFR autocrine loop for cell proliferation. We also demonstrated that AREG can increase EGFR stability and promote EGFR localization to the plasma membrane. In the presented dissertation we successfully knocked-down AREG expression in SUM-149 cells by lenti-viral infection of AREG shRNA. In the absence of AREG expression, SUM-149 cell growth was slowed, but not completely inhibited. Furthermore, cells infected with AREG shRNA constructs showed an increase in EGFR protein expression by western blot. Immunofluorescence and confocal microscopy showed that following AREG knock-down, EGFR continued to localize to the …

Frazzled And Abelson Interact To Regulate The Actin Cytoskeleton In Drosophila, Bridget Elsa Varughese

Wayne State University Dissertations

Guidance receptors such as Frazzled affect cell shape and motility by directly or indirectly modulating the cytoskeleton. Fra is particularly needed for the formation of the posterior commissures in a developing Drosophila embryo. The cytoplasmic tyrosine kinase, Abelson Kinase (Abl) enhances the loss of commissures observed in fra mutant. Abl physically interacts with Frazzled to help guide commissural axons across the midline. Furthermore, the loss of commissural axons is only seen when the actin dynamics are perturbed. Abl is also known to regulate actin-dependent processes underlying formation of filopodia, microspikes and membrane ruffles. So, we established a Drosophila S2 cell …

Study Of Protein-Rna Interactions Using Fluorescence Resonance Energy Transfer (Fret) And Single-Molecule Fret, Rajan Lamichhane

Wayne State University Dissertations

In the cell, RNA and protein, interact to form ribonucleoprotein complexes (RNPs) that have vital structural, catalytic and regulatory roles. Despite their functional importance, the mechanistic details and dynamics of RNPs are poorly understood. Single-molecule Fluorescence Resonance Energy Transfer (smFRET) techniques that provide information about heterogeneity and dynamic behaviors of molecules have been developed to investigate inter- and intra-molecular interactions. Here we have used FRET in combination with smFRET to study three very different RNP systems.

Alternative splicing is a highly regulated biological process that plays a crucial role in proteomic diversity in eukaryotes. One splicing regulator, PTB, has been …

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 …

Molecular Mechanisms Of Snare Assembly And Expulsion Of Intravesicular Contents In Cell Secretion, Leah Jiyoung Zhang

Wayne State University Dissertations

For nearly half a century, it was believed that during cell secretion, membrane-bound secretory vesicles completely merge at the cell plasma membrane resulting in the diffusion of intra-vesicular contents to the cell exterior and the compensatory retrieval of the excess membrane by endocytosis. This explanation made no sense or logic, since following cell secretion partially empty vesicles accumulate as demonstrated in electron micrographs. Furthermore, with the `all or none' mechanism of cell secretion by complete merger of secretory vesicle membrane at the cell plasma membrane, the cell is left with little regulation and control of the amount of content release. …

Development Of Chemical Inducers Of Dimerization For Screening Competitive Histone Deactelyase Inhibitors, Emily Lynn Aubie

Wayne State University Dissertations

Histone Deacetylase (HDAC) proteins are transcriptional regulators that affect histone proteins, which are involved in packaging of DNA into chromosomes. HDACs have been linked to the proliferation of cancer through their role in transcriptional regulation. Due to these findings, HDAC inhibitors have been explored as anti-cancer agents. Several HDAC inhibitors are currently in various stages of clinical trials, and the inhibitor suberoyl anilide hydroxamic acid (SAHA) has been FDA approved for treatment of cutaneous T-Cell lymphoma. Currently, most of the known HDAC inhibitors are non-selective, which causes non-specific binding to the active sites of all HDAC isoforms, including those not …