Biochemistry, Biophysics, and Structural Biology Commons^™

New Open Conformation Of Smyd3 Implicates Conformational Selection And Allostery, Nicholas Spellmon, Xiaonan Sun, Wen Xue, Joshua Holcomb, Srinivas Chakravarthy, Weifeng Shang, Brian Fp Edwards, Nualpun Sirinupong, Chunying Li, Zhe Yang

Biochemistry and Molecular Biology Faculty Publications

SMYD3 plays a key role in cancer cell viability, adhesion, migration and invasion. SMYD3 promotes formation of inducible regulatory T cells and is involved in reducing autoimmunity. However, the nearly “closed” substrate-binding site and poor in vitro H3K4 methyltransferase activity have obscured further understanding of this oncogenically related protein. Here we reveal that SMYD3 can adopt an “open” conformation using molecular dynamics simulation and small-angle X-ray scattering. This ligand-binding-capable open state is related to the crystal structure-like closed state by a striking clamshell-like inter-lobe dynamics. The two states are characterized by many distinct structural and dynamical differences and the conformational …

Development Of A Novel Class Of Chemicals For Labeling Abasic Sites In Cellular Dna And Killing Cancer Cells, Shanqiao Wei

Wayne State University Dissertations

Abasic (AP) sites are the most common type of lesions in DNA. Numerous endogenous and exogenous agents and cellular processes can induce the formation of AP sites in DNA. If left unrepaired, the deleterious AP sites cause mutagenesis and cytotoxicity. Methoxyamine is known to react with AP sites and block base excision repair. Another alkoxyamine, aldehyde-reactive probe (ARP) tags AP sites with a biotin and has been widely used to quantify these sites. In this study, I have combined both these abilities into one alkoxyamine, AA3, which reacts toward AP sites with better reactivity than ARP at physiological pH. Additionally, …

Insights Into De Novo Fes-Cluster Biogenesis Via The Eukaryotic Fes-Cluster (Isc) Pathway In Vitro, Stephen Paul Dzul

Wayne State University Dissertations

Fe-S clusters are iron-containing cofactors utilized by numerous proteins within several biological pathways essential to life. In eukaryotes, the primary pathway for Fe-S cluster production is the iron-sulfur cluster (ISC) pathway. The eukaryotic ISC pathway, localized primarily within the mitochondria, has been best characterized within Saccharomyces cerevisiae. In yeast, de novo Fe-S cluster formation is accomplished through coordinated assembly of the substrates iron and sulfur on the primary scaffold assembly protein “Isu1”. The sulfur used for cluster assembly is provided by the cysteine desulfurase “Nfs1”, a protein that works in union with its accessory protein “Isd11”. Frataxin “Yfh1” helps direct …

Development Of Gamma-Modified Atp Analogs To Study Kinase-Catalyzed Phosphorylations, Ahmed Eid Fouda

Wayne State University Dissertations

Kinase-catalyzed protein phosphorylation is one of the most important post-translational modifications that controls cascades of biochemical reactions. Irregularities in phosphorylation result in many diseases, such as diabetes mellitus, Parkinsons, and cancer. The development of new methods to monitor kinase-catalyzed phosphorylation is needed to decipher details of normal and diseased cell signaling. The Pflum lab recently developed several -modified ATP analogs to study kinase catalyzed phosphorylation reactions. The -modified ATP analogs have different tags, such as biotin for substrate labeling or aryl-azide for kinase substrates identification. Unfortunately, use of -modified ATP analogs was limited to in vitro studies due to the …

Effective Drug Treatment Induces Drug Resistance Through Rapid Genome Alteration-Mediated Cancer Evolution, Steven Horne

Wayne State University Dissertations

The central paradox associated with current cancer therapeutic strategies is initially effective treatment, which eliminates a high tumor cell count, consistently results in successful drug resistance. Mathematical and evolutionary modeling have previously suggested that therapeutic intervention could provide selective pressure for the expansion of resistant variants. Drug-related stress has been associated with genome chaos, a common phenomenon in cancer characterized as rapid, stochastic genomic fragmentation and reorganization. Since cancer represents an evolutionary process, analysis within the context of genome-mediated cancer evolution can shed light on this key problem of therapeutics. We propose that genomic change is a general response to …

An Analysis Of The Interaction Between Sin3 And Methionine Metabolism In Drosophila, Mengying Liu

Wayne State University Dissertations

Chromatin modification and cellular metabolism are tightly connected. The mechanism for this cross-talk, however, remains incompletely understood. SIN3 controls histone acetylation through association with the histone deacetylase RPD3. In this study, my major goal is to explore the mechanism of how SIN3 regulates cellular metabolism.

Methionine metabolism generates the major methyl donor S-adenosylmethionine (SAM) for histone methylation. In collaboration with others, I report that reduced levels of some enzymes involved in methionine metabolism and histone demethylases lead to lethality, as well as wing development and cell proliferation defects in Drosophila melanogaster. Additionally, disruption of methionine metabolism can directly affect histone …

Investigating The Role Of Dna Polymerase Beta In The Aging Phenotype Of Down Syndrome, Aqila Ahmed Ahmed

Wayne State University Dissertations

Down syndrome (DS) is a chromosomal condition characterized by accelerated aging that has yet to be directly linked to a DNA repair defect. Reduced PolB and unrepaired damage from oxidative stress observed in DS, point toward defective base excision repair (BER). In this study, we report that low PolB transcript correlates with increased markers of senescence. The gene dosage effect of Trisomy 21 is likely the source for PolB downregulation. We show that the HSA21-localized miR-155 overexpression correlates with a decrease in Creb1 and PolB, thus establishing a putative regulatory pathway. Data from the DS mouse model, Ts65Dn, reveal low …

A Critical Role Of Cxcr2 Pdz Motif-Mediated Interactions In Endothelial Progenitor Cell Homing And Angiogenesis, Yuning Hou

Wayne State University Dissertations

Bone marrow-derived endothelial progenitor cells (EPCs) participate in postnatal vascularization in response to growth factors, cytokines, and chemokines. Chemokine receptor CXCR2 and its cognate ligands are reported to mediate EPC recruitment and angiogenesis. CXCR2 possesses a consensus PSD-95/DlgA/ZO-1 (PDZ) motif at its carboxyl terminus. The PDZ motif has been reported to regulate cellular signaling and functions. Here we investigated the potential role of the PDZ motif in CXCR2-mediated EPC motility and angiogenesis. We have found that introducing exogenous CXCR2 C-terminus significantly attenuated in vitro EPC migration and angiogenic activities in response to CXCR2 ligands, as well as in vivo EPC …

The Effects Of Courtship And Pairing Behavior On The Nonapeptide And Noradrenergic Systems Of Adult Male And Female Zebra Finches, Erin Lowrey Ondercin

Wayne State University Dissertations

Social relationships are complex and likely involve the multiple neural circuits, including those involved in learning, memory, motivation, and attention. Two neurotransmitter pathways highly involved in these neural circuits are norepinephrine (NE) and the nonapeptides, vasopressin (AVP) and oxytocin (OT). There is extensive research implicating a role for the nonapeptides in trust, sociality, parental care, and romantic relationships. There is little direct evidence for the role of nonapeptides in monogamous relationships in any species other than the prairie vole (Goodson 2013). However, there is evidence that nonapeptides are important in pair bonding for both male and female zebra finches (Lowrey …

Investigation Of Mutations In Nuclear Genes That Affect The Atp Synthase, Russell Dsouza

Wayne State University Dissertations

The F1 domain is the catalytic subunit of the mitochondrial ATP synthase. Studies with respiratory-deficient yeast identified ATP1 and ATP2 as nuclear genes encoding the alpha and beta subunits, respectively, of the mitochondrial F1-ATPase. The mutations in the atp1 and atp2 genes were cloned and sequenced, and they appear to affect the ATP synthase. Most yeast strains with mutations in the or the subunit primarily show an F1 assembly defective phenotype. This feature is similar to the assembly-defective mutants missing the chaperones required for assembly of the F1 oligomer or either the alpha/beta subunits.

Some of the atp2 and atp1 …

The Effects Of The N-Terminal Extensions Of Cardiac Troponins On The Ca2+ Regulation Of Myosin Atpase Kinetics In Cardiac Myofibrils, Laura Gunther

Wayne State University Dissertations

Contraction of cardiac muscle is the basis of heart function. Heart failure, i.e., weakened contraction of cardiac muscle is the most common cause of morbidity and mortality of heart diseases. Cardiac muscle contraction is regulated by calcium via the function of troponin, a protein complex associated with the myofilaments in muscle cells. The cardiac troponin subunits T (cTnT) and I (cTnI) have unique N-terminal extensions that can be selectively removed by restrictive proteolysis during cardiac adaptation to physiological and pathological stresses, indicating a role of these proteins in modulating cardiac contraction. This study aims to understand the effects of the …

A Novel Role For Repetitive Sequences In Recognition Of The Drosophila Melanogaster X Chromosome, Sonal Suresh Joshi

Wayne State University Dissertations

In humans and fruit flies, males have one X chromosome while females have two. This imbalance in gene dosage is potentially lethal, and the process of dosage compensation corrects it. The MSL (Male Specific Lethal) complex, which is composed of five proteins and one of two functionally redundant long non-coding roX (RNA on the X) RNAs, brings about dosage compensation in Drosophila melanogaster. In fruit fly dosage compensation, all the genes on the single male X chromosome are upregulated approximately twofold, via chromatin modifications, to equalize gene dosage with the two X chromosomes of females. This process calls for highly …

Novel Regulatory Mechanisms Of Inositol Biosynthesis In Saccharomyces Cerevisiae And Mammalian Cells, And Implications For The Mechanism Underlying Vpa-Induced Glucose 6-Phosphate Depletion, Wenxi Yu

Wayne State University Dissertations

Myo-inositol is the precursor of all inositol containing molecules, including inositol phosphates, phosphoinositides and glycosylphosphatidylinositols, which are signaling molecules involved in many critical cellular functions. Perturbation of inositol metabolism has been linked to neurological disorders. Although several widely-used anticonvulsants and mood-stabilizing drugs have been shown to exert inositol depletion effects, the mechanisms of action of the drugs and the role of inositol in these diseases are not understood. Elucidation of the molecular control of inositol synthesis will shed light on the pathologies of inositol related illnesses.

In Saccharomyces cerevisiae, deletion of the four glycogen synthase kinase-3 genes, MCK1, MRK1, MDS1, …

Structural Characterization And Therapeutic Utility Of The Proton-Coupled Folate Transporter, Michael Roy Wilson

Wayne State University Dissertations

Folate is a B9 vitamin essential to DNA synthesis. The proton-coupled folate transporter (PCFT) is a newly discovered proton/folate symporter with an acidic pH optimum and broad expression across a variety of solid tumor types, with limited expression in normal tissues. Several antifolate molecules have been developed as cancer therapeutics, although these classical antifolates display numerous off-target effects due to transport by the ubiquitous reduced folate carrier (RFC). In this dissertation, we determine the roles of multiple PCFT structure/function domains, and develop PCFT-specific antifolates to target solid tumors. We utilize substituted cysteine accessibility methods (SCAM) to identify a novel reentrant …

A Five Residue Insertion Between Codons 28 And 29 Of The Hiv-1 Protease Gene Reduces The Replicative Capacity Of The Virus, Cathy Mcleod

Wayne State University Theses

HIV-1 protease (PR) is a 99 amino acid protein responsible for cleavage of the viral polyprotein. We have identified a novel clinical isolate, MDR/28, which contains a five residue insertion between codons 28 and 29 of a multi-drug resistant (MDR) PR. This clinical isolate displays reduced viral replicative capacity compared to the wild-type. As opposed to drug-resistance mutations, studies on insertions remain largely underrepresented in the literature, and the consequences of such insertions are largely unknown. To understand the mechanism leading to reduced replicative capacity, three PR models were created and subjected to 40ns molecular dynamics simulations: MDR/28, wild type, …

Contribution Of Cx3cr1/Fractalkine (Cx3cl1) Axis To The Progression Of Non-Small Cell Lung Cancer (Nsclc), Rhonda Prince

Wayne State University Theses

A thesis is presented on the characterization of the contribution of the chemokine axis, CX_3CR1/Fractalkine, to the progression of Non-Small Cell Lung Cancer (NSCLC). Cancer is the second leading cause of death in the United States, and Lung cancer is one of the four leading causes of the disease. Carcinoma cells, unlike their normal counterparts, gain the ability to express chemokine receptors. Understanding if/how this gain of expression contributes to the progression of cancer could provide a lucrative therapeutic target. Goals of the study include investing if the NSCLC cell line A549, an adenocarcinoma cell line, express the chemokine receptor …

Structure Function Studies Of Hiv-1 Protease, Bradley James Keusch

Wayne State University Theses

HIV-1 is the causative agent of the devastating human disease Acquired Immunodeficiency Syndome (AIDS). While much progress has been made over the past two decades, HIV-1 remains a major global health concern. HIV-1 protease is 99-amino acid homodimer aspartyl protease that is essential to the life cycle of HIV. This has rendered it an attractive and very successful drug target. However, due to the high error rate of the HIV -1 reverse transcriptase, drug resistance mutations in the protease can develop very rapidly in some patients, rendering current protease inhibitors (one of the main classes of drug in common antiretroviral …

The Development Of Peptide Ligands To Target H69 Rrna, Danielle Nicole Dremann

Wayne State University Dissertations

ABSTRACT

THE DEVELOPMENT OF PEPTIDE LIGANDS TO TARGET H69

by

DANIELLE NICOLE DREMANN

December 2015

Advisor: Prof. Christine S. Chow

Major: Chemistry (Biochemistry)

Degree: Doctor of Philosophy

In the development of peptide ligands to target H69, SPPS and ESI MS was used to determine if 1) peptides could bind to modified H69 and 2) if increased affinity for the target RNA could be enhanced with modification. An alanine and arginine scan was synthesized and tested for this determination. Selected peptides were then tested using biophysical techniques such as circular dichroism and isothermal titration calorimetry. An assay was also designed to …

Identification Of Lipolysis-Derived Lipid Mediators And The Activation Of A Pro-Inflammatory Cyclooxygenase Pathway, Via Cyclooxygenase-2, In Adipose Tissue, Allison Christine Gartung

Wayne State University Dissertations

Adipose lipolysis triggers pro-inflammatory responses that play critical roles in insulin resistance and associated metabolic syndrome. However, pro-inflammatory mediators generated by adipose lipolysis, particularly in the context of lipid mediators, are poorly defined. In this study, the activation of the beta-3 adrenergic receptor (ADRB3)/hormone sensitive lipase (HSL) pathway, a well-employed model system, was utilized to characterize the pro-inflammatory lipid mediators generated by adipose lipolysis. Cultured adipocytes were treated with an ADRB3 agonist and the media was analyzed for eicosanoids using the LC-MS/MS lipidomic method. Among the characterized eicosanoids, I found that approximately 43 metabolites generated by cyclooxygenase (COX), lipoxygenase, and …

Genome Wide Analysis Identifies Sphingolipid Metabolism As A New Target Of Valproic Acid, Shyamalagauri Jadhav Jadhav

Wayne State University Dissertations

Bipolar disorder (BD), which is characterized by depression and mania, affects about 1% of the total world population. Current treatments are effective in only 40-60% of cases and cause severe side effects. Valproic acid (VPA), a branched short-chain fatty acid, is one of the most widely used drugs for the treatment of BD. Although many hypotheses have been postulated to explain the molecular mechanism of action of this drug in BD, the therapeutic mechanism is not understood. This knowledge gap has hampered the development of new drugs to treat this disorder. To identify candidate pathways affected by VPA, I performed …

Regulation Of Cytochrome C Functions By Phosphorylation, Gargi Mahapatra

Wayne State University Dissertations

The long term goal of my thesis research is to understand how tissue-specific

phosphorylations on the small mitochondrial protein, cytochrome c (Cytc), regulate its

functions, under both physiologically healthy and stressed conditions, and to identify the

cell signaling pathways targeting Cytc. Cytc is a functionally diverse protein that carries

electrons in the electron transport chain and plays a critical role in cellular apoptosis, two

diverse pathways that maintain cellular health that are active under diverse conditions.

Since Cytc plays a pivotal role in both these highly divergent pathways, regulation of the

protein is very important—phosphorylation of the protein under physiological …

Modeling The Mechanism Underlying Environmental And Genetic Determinants Of Gene Expression And Complex Traits, Gregory Alan Moyerbrailean

Wayne State University Dissertations

Advances in next-generation sequencing technologies and functional genomics strategies have allowed researchers to identify both common and rare genetic variation, to deeply profile gene expression, and even to determine regions of active gene transcription.

While these technologies and strategies have contributed greatly to our understanding of complex traits and diseases, there are many biological questions and analytical issues to be addressed.

Genome-wide association studies (GWAS) have successfully identified large numbers of genetic variants associated with complex traits and diseases. However, in many cases the mechanistic link between the phenotype and associated variant remains unclear. This may be because most variants …

An Investigation Into The Molecular Basis Underlying Enhancement Of Transcription By The Intron In Budding Yeast, Neha Agarwal Agarwal

Wayne State University Dissertations

It is now quite evident that the introns, which are removed from the primary transcript by the process of splicing, are involved in a variety of important functions in eukaryotic cells. One of the evolutionarily conserved functions of introns is their role in regulating transcription of genes that harbors them. This effect of a splicing-competent intron on transcription is known as ‘Intron-Mediated Enhancement of transcription’ (IME). It has been observed that the intron-containing genes are often transcribed more efficiently than non-intronic genes. However, the molecular mechanism underlying IME in budding yeast and higher eukaryotes is not entirely clear, and that …

Characterization Of The Yeast Cysteine Desulfurase Complex Within The Mitochondrial Fe-S Cluster Biogenesis, Dulmini Pabasara Barupala

Wayne State University Dissertations

Disrupted iron homeostasis within the human body materializes as various disorders. Pathophysiology of many of them relates to iron induced oxidative damage to key cellular components caused by iron accumulation within the tissues. Pertaining to the growing occurrence, cost of patient care and devastating burden associated with these diseases, the call for understanding the role of iron homeostasis within these disorders becomes inevitable. Being an abundant iron containing cofactor, the role of Fe-S clusters in cellular iron homeostasis is indisputable in the case of Friedreich’s ataxia, a disease caused by a deficiency in the protein frataxin that is indispensable during …

Studies Towards Broadening The Substrate Profile And Regulation Of Histone Deacetylase 1, Dhanusha Ashanthi Nalawansha

Wayne State University Dissertations

Aberrant expression of histone deacetylase 1 (HDAC1) is implicated in multiple diseases, including cancer. As a consequence, HDAC1 has emerged as an important therapeutic target for drug development. HDAC1 regulates key cellular processes, such as cell proliferation, apoptosis, and cell survival, by deacetylating both histone and non-histone substrates. Due to the lack of simple tools to identify physiological substrates of HDAC1, the full spectrum of HDAC1 activities in the cell remains unclear. Here, we employed a substrate trapping strategy to identify cellular substrates of HDAC1. Using this approach, we identified mitosis-related protein Eg5 as a substrate. HDAC1 colocalizes with Eg5 …

Cardiolipin Is Required For Optimal Acetyl-Coa Metabolism, Vaishnavi Raja

Wayne State University Dissertations

The phospholipid cardiolipin (CL) is crucial for many cellular functions and signaling pathways, both inside and outside of mitochondria. My thesis focuses on the role of CL in energy metabolism. Many reactions of electron transport and oxidative phosphorylation, the transport of metabolites needed for these processes, and the stabilization of electron transport chain supercomplexes, require CL. Recent studies indicate that CL is required for the synthesis of iron-sulfur (Fe-S) co-factors, which are essential for numerous metabolic pathways. Activation of carnitine-acetylcarnitine translocase, which transports acetyl-CoA into the mitochondria, is CL dependent. The presence of substantial amounts of CL in the peroxisomal …