Life Sciences Commons^™

Linker Histone H1 And H3k56 Acetylation Are Antagonistic Regulators Of Nucleosome Dynamics, Morgan Bernier, Yi Luo, Kingsley C. Nwokelo, Michelle Goodwin, Sarah J. Dreher, Pei Zhang, Mark R. Parthun, Yvonne N. Fondufe-Mittendorf, Jennifer J. Ottesen, Michael G. Poirier

Molecular and Cellular Biochemistry Faculty Publications

H1 linker histones are highly abundant proteins that compact nucleosomes and chromatin to regulate DNA accessibility and transcription. However, the mechanisms that target H1 regulation to specific regions of eukaryotic genomes are unknown. Here we report fluorescence measurements of human H1 regulation of nucleosome dynamics and transcription factor (TF) binding within nucleosomes. H1 does not block TF binding, instead it suppresses nucleosome unwrapping to reduce DNA accessibility within H1-bound nucleosomes. We then investigated H1 regulation by H3K56 and H3K122 acetylation, two transcriptional activating histone post translational modifications (PTMs). Only H3K56 acetylation, which increases nucleosome unwrapping, abolishes H1.0 reduction of TF …

Differential Impact Of Lpg-And Pg-Deficient Leishmania Major Mutants On The Immune Response Of Human Dendritic Cells, Michelle A. Favila, Nicholas S. Geraci, Asha Jayakumar, Suzanne Hickerson, Janet Mostrom, Salvatore J. Turco, Stephen M. Beverley, Mary Ann Mcdowell

Molecular and Cellular Biochemistry Faculty Publications

BACKGROUND: Leishmania major infection induces robust interleukin-12 (IL12) production in human dendritic cells (hDC), ultimately resulting in Th1-mediated immunity and clinical resolution. The surface of Leishmania parasites is covered in a dense glycocalyx consisting of primarily lipophosphoglycan (LPG) and other phosphoglycan-containing molecules (PGs), making these glycoconjugates the likely pathogen-associated molecular patterns (PAMPS) responsible for IL12 induction.

METHODOLOGY/PRINCIPAL FINDINGS: Here we explored the role of parasite glycoconjugates on the hDC IL12 response by generating L. major Friedlin V1 mutants defective in LPG alone, (FV1 lpg1-), or generally deficient for all PGs, (FV1 lpg2-). Infection with metacyclic, infective …

A Cytosolic Multiprotein Complex Containing P85Α Is Required For Β-Catenin Activation In Colitis And Colitis-Associated Cancer, Tatiana Goretsky, Emily M. Bradford, Hyunji Ryu, Maryam Tahir, Mary Pat Moyer, Tianyan Gao, Linheng Li, Terrence A. Barrett

Internal Medicine Faculty Publications

Wnt/β-catenin signaling is required for crypt structure maintenance. We previously observed nuclear accumulation of Ser-552 phosphorylated β-catenin (pβ-Cat^Ser-552) in intestinal epithelial cells (IEC) during colitis and colitis-associated cancer. Data here delineate a novel multiprotein cytosolic complex (MCC) involved in β-catenin signaling in the intestine. The MCC contains p85α, the class IA subunit of PI3K, along with β-catenin, 14-3-3ζ, Akt, and p110α. MCC levels in IEC increase in colitis and colitis-associated cancer patients. IEC-specific p85α-deficient (p85^ΔIEC) mice develop more severe dextran sodium …

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O₃(g) by catechol γ_O3 = (7.49 ± 0.35) × 10^–6 occurs for …

Mechanistic Insights Into Glucan Phosphatase Activity Against Polyglucan Substrates, David A. Meekins, Madushi Raththagala, Kyle D. Auger, Benjamin D. Turner, Diana Santelia, Oliver Kötting, Matthew S. Gentry, Craig W. Vander Kooi

Molecular and Cellular Biochemistry Faculty Publications

Glucan phosphatases are central to the regulation of starch and glycogen metabolism. Plants contain two known glucan phosphatases, Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2), which dephosphorylate starch. Starch is water-insoluble and reversible phosphorylation solubilizes its outer surface allowing processive degradation. Vertebrates contain a single known glucan phosphatase, laforin, that dephosphorylates glycogen. In the absence of laforin, water-soluble glycogen becomes insoluble, leading to the neurodegenerative disorder Lafora Disease. Because of their essential role in starch and glycogen metabolism glucan phosphatases are of significant interest, yet a comparative analysis of their activities against diverse glucan substrates has not been established. …

Autophagy Is Induced Upon Platelet Activation And Is Essential For Hemostasis And Thrombosis, Madhu M. Ouseph, Yunjie Huang, Meenakshi Banerjee, Smita Joshi, Laura Macdonald, Yu Zhong, Huijuan Liu, Xianting Li, Binggang Xiang, Guoying Zhang, Masaaki Komatsu, Zhenyu Yue, Zhenyu Li, Brian Storrie, Sidney W. Whiteheart, Qing Jun Wang

Molecular and Cellular Biochemistry Faculty Publications

Autophagy is important for maintaining cellular homeostasis, and thus its deficiency is implicated in a broad spectrum of human diseases. Its role in platelet function has only recently been examined. Our biochemical and imaging studies demonstrate that the core autophagy machinery exists in platelets, and that autophagy is constitutively active in resting platelets. Moreover, autophagy is induced upon platelet activation, as indicated by agonist-induced loss of the autophagy marker LC3II. Additional experiments, using inhibitors of platelet activation, proteases, and lysosomal acidification, as well as platelets from knockout mouse strains, show that agonist-induced LC3II loss is a consequence of platelet signaling …

Genome-Wide Profiling Of Parp1 Reveals An Interplay With Gene Regulatory Regions And Dna Methylation, Narasimharao Nalabothula, Taha Al-Jumaily, Abdallah M. Eteleeb, Robert M. Flight, Shao Xiaorong, Hunter Moseley, Eric C. Rouchka, Yvonne N. Fondufe-Mittendorf

Molecular and Cellular Biochemistry Faculty Publications

Poly (ADP-ribose) polymerase-1 (PARP1) is a nuclear enzyme involved in DNA repair, chromatin remodeling and gene expression. PARP1 interactions with chromatin architectural multi-protein complexes (i.e. nucleosomes) alter chromatin structure resulting in changes in gene expression. Chromatin structure impacts gene regulatory processes including transcription, splicing, DNA repair, replication and recombination. It is important to delineate whether PARP1 randomly associates with nucleosomes or is present at specific nucleosome regions throughout the cell genome. We performed genome-wide association studies in breast cancer cell lines to address these questions. Our studies show that PARP1 associates with epigenetic regulatory elements genome-wide, such as active histone …

Pharmacodynamic Assays To Facilitate Preclinical And Clinical Development Of Pre-Mrna Splicing Modulatory Drug Candidates, Yihui Shi, Amanda S. Joyner, William Shadrick, Gustavo Palacios, Chandraiah Lagisetti, Philip M. Potter, Lidia C. Sambucetti, Stefan Stamm, Thomas R. Webb

Molecular and Cellular Biochemistry Faculty Publications

The spliceosome has recently emerged as a new target for cancer chemotherapy and novel antitumor spliceosome targeted agents are under development. Here, we describe two types of novel pharmacodynamic assays that facilitate drug discovery and development of this intriguing class of innovative therapeutics; the first assay is useful for preclinical optimization of small-molecule agents that target the SF3B1 spliceosomal protein in animals, the second assay is an ex vivo validated, gel-based assay for the measurement of drug exposure in human leukocytes. The first assay utilizes a highly specific bioluminescent splicing reporter, based on the skipping of exons 4-11 of a …

A Less-Biased Analysis Of Metalloproteins Reveals Novel Zinc Coordination Geometries, Sen Yao, Robert M. Flight, Eric C. Rouchka, Hunter N. B. Moseley

Molecular and Cellular Biochemistry Faculty Publications

Zinc metalloproteins are involved in many biological processes and play crucial biochemical roles across all domains of life. Local structure around the zinc ion, especially the coordination geometry (CG), is dictated by the protein sequence and is often directly related to the function of the protein. Current methodologies in characterizing zinc metalloproteins' CG consider only previously reported CG models based mainly on nonbiological chemical context. Exceptions to these canonical CG models are either misclassified or discarded as "outliers." Thus, we developed a less-biased method that directly handles potential exceptions without pre-assuming any CG model. Our study shows that numerous exceptions …

The Mitochondrial Peptidase Pitrilysin Degrades Islet Amyloid Polypeptide In Beta-Cells, Hanjun Guan, K. Martin Chow, Eunsuk Song, Nirmal Verma, Florin Despa, Louis B. Hersh

Molecular and Cellular Biochemistry Faculty Publications

Amyloid formation and mitochondrial dysfunction are characteristics of type 2 diabetes. The major peptide constituent of the amyloid deposits in type 2 diabetes is islet amyloid polypeptide (IAPP). In this study, we found that pitrilysin, a zinc metallopeptidase of the inverzincin family, degrades monomeric, but not oligomeric, islet amyloid polypeptide in vitro. In insulinoma cells when pitrilysin expression was decreased to 5% of normal levels, there was a 60% increase in islet amyloid polypeptide-induced apoptosis. In contrast, overexpression of pitrilysin protects insulinoma cells from human islet amyloid polypeptide-induced apoptosis. Since pitrilysin is a mitochondrial protein, we used immunofluorescence staining …

An Extended Polyanion Activation Surface In Insulin Degrading Enzyme, Eun Suk Song, Mehmet Ozbil, Tingting Zhang, Michael Sheetz, David Lee, Danny Tran, Sheng Li, Rajeev Prabhakar, Louis B. Hersh, David W. Rodgers

Molecular and Cellular Biochemistry Faculty Publications

Insulin degrading enzyme (IDE) is believed to be the major enzyme that metabolizes insulin and has been implicated in the degradation of a number of other bioactive peptides, including amyloid beta peptide (Aβ), glucagon, amylin, and atrial natriuretic peptide. IDE is activated toward some substrates by both peptides and polyanions/anions, possibly representing an important control mechanism and a potential therapeutic target. A binding site for the polyanion ATP has previously been defined crystallographically, but mutagenesis studies suggest that other polyanion binding modes likely exist on the same extended surface that forms one wall of the substrate-binding chamber. Here we use …

Intra-Domain Cross-Talk Regulates Serine-Arginine Protein Kinase 1-Dependent Phosphorylation And Splicing Function Of Transformer 2Β1, Michael A. Jamros, Brandon E. Aubol, Malik M. Keshwani, Zhaiyi Zhang, Stefan Stamm, Joseph A. Adams

Molecular and Cellular Biochemistry Faculty Publications

Transformer 2β1 (Tra2β1) is a splicing effector protein composed of a core RNA recognition motif flanked by two arginine-serine-rich (RS) domains, RS1 and RS2. Although Tra2β1-dependent splicing is regulated by phosphorylation, very little is known about how protein kinases phosphorylate these two RS domains. We now show that the serine-arginine protein kinase-1 (SRPK1) is a regulator of Tra2β1 and promotes exon inclusion in the survival motor neuron gene 2 (SMN2). To understand how SRPK1 phosphorylates this splicing factor, we performed mass spectrometric and kinetic experiments. We found that SRPK1 specifically phosphorylates 21 serines in RS1, a process facilitated …

Preventing Farnesylation Of The Dynein Adaptor Spindly Contributes To The Mitotic Defects Caused By Farnesyltransferase Inhibitors, Andrew J. Holland, Rita M. Reis, Sherry Niessen, Cláudia Pereira, Douglas A. Andres, H. Peter Spielmann, Don W. Cleveland, Arshad Desai, Reto Gassmann

Molecular and Cellular Biochemistry Faculty Publications

The clinical interest in farnesyltransferase inhibitors (FTIs) makes it important to understand how these compounds affect cellular processes involving farnesylated proteins. Mitotic abnormalities observed after treatment with FTIs have so far been attributed to defects in the farnesylation of the outer kinetochore proteins CENP-E and CENP-F, which are involved in chromosome congression and spindle assembly checkpoint signaling. Here we identify the cytoplasmic dynein adaptor Spindly as an additional component of the outer kinetochore that is modified by farnesyltransferase (FTase). We show that farnesylation of Spindly is essential for its localization, and thus for the proper localization of dynein and its …

Transcriptional Activity Of The Islet Β Cell Factor Pdx1 Is Augmented By Lysine Methylation Catalyzed By The Methyltransferase Set7/9, Aarthi V. Maganti, Bernhard Maier, Sarah A. Tersey, Megan L. Sampley, Amber L. Mosley, Sabire Özcan, Boobalan Pachaiyappan, Patrick M. Woster, Chad S. Hunter, Roland Stein, Raghavendra G. Mirmira

Molecular and Cellular Biochemistry Faculty Publications

The transcription factor Pdx1 is crucial to islet β cell function and regulates target genes in part through interaction with coregulatory factors. Set7/9 is a Lys methyltransferase that interacts with Pdx1. Here we tested the hypothesis that Lys methylation of Pdx1 by Set7/9 augments Pdx1 transcriptional activity. Using mass spectrometry and mutational analysis of purified proteins, we found that Set7/9 methylates the N-terminal residues Lys-123 and Lys-131 of Pdx1. Methylation of these residues occurred only in the context of intact, full-length Pdx1, suggesting a specific requirement of secondary and/or tertiary structural elements for catalysis by Set7/9. Immunoprecipitation assays and mass …

Inorganic Arsenic-Induced Cellular Transformation Is Coupled With Genome Wide Changes In Chromatin Structure, Transcriptome And Splicing Patterns, Caitlyn Riedmann, Ye Ma, Manana Melikishvili, Steven Grason Godfrey, Zhuo Zhang, Kuey-Chu Chen, Eric C. Rouchka, Yvonne N. Fondufe-Mittendorf

Molecular and Cellular Biochemistry Faculty Publications

BACKGROUND: Arsenic (As) exposure is a significant worldwide environmental health concern. Low dose, chronic arsenic exposure has been associated with a higher than normal risk of skin, lung, and bladder cancer, as well as cardiovascular disease and diabetes. While arsenic-induced biological changes play a role in disease pathology, little is known about the dynamic cellular changes resulting from arsenic exposure and withdrawal.

RESULTS: In these studies, we sought to understand the molecular mechanisms behind the biological changes induced by arsenic exposure. A comprehensive global approach was employed to determine genome-wide changes to chromatin structure, transcriptome patterns and splicing patterns in …

Analysis Of Cathepsin And Furin Proteolytic Enzymes Involved In Viral Fusion Protein Activation In Cells Of The Bat Reservoir Host, Farah El Najjar, Levi Lampe, Michelle L. Baker, Lin-Fa Wang, Rebecca Ellis Dutch

Molecular and Cellular Biochemistry Faculty Publications

Bats of different species play a major role in the emergence and transmission of highly pathogenic viruses including Ebola virus, SARS-like coronavirus and the henipaviruses. These viruses require proteolytic activation of surface envelope glycoproteins needed for entry, and cellular cathepsins have been shown to be involved in proteolysis of glycoproteins from these distinct virus families. Very little is currently known about the available proteases in bats. To determine whether the utilization of cathepsins by bat-borne viruses is related to the nature of proteases in their natural hosts, we examined proteolytic processing of several viral fusion proteins in cells derived from …

Structural Mechanism Of Laforin Function In Glycogen Dephosphorylation And Lafora Disease, Madushi Raththagala, M. Kathryn Brewer, Matthew W. Parker, Amanda R. Sherwood, Brian K. Wong, Simon Hsu, Travis M. Bridges, Bradley C. Paasch, Lance M. Hellman, Satrio Husodo, David A. Meekins, Adam O. Taylor, Benjamin D. Turner, Kyle D. Auger, Vikas V. Dukhande, Srinivas Chakravarthy, Pascual Sanz, Virgil L. Woods Jr., Sheng Li, Craig Vander Kooi, Matthew S. Gentry

Molecular and Cellular Biochemistry Faculty Publications

Glycogen is the major mammalian glucose storage cache and is critical for energy homeostasis. Glycogen synthesis in neurons must be tightly controlled due to neuronal sensitivity to perturbations in glycogen metabolism. Lafora disease (LD) is a fatal, congenital, neurodegenerative epilepsy. Mutations in the gene encoding the glycogen phosphatase laforin result in hyperphosphorylated glycogen that forms water-insoluble inclusions called Lafora bodies (LBs). LBs induce neuronal apoptosis and are the causative agent of LD. The mechanism of glycogen dephosphorylation by laforin and dysfunction in LD is unknown. We report the crystal structure of laforin bound to phosphoglucan product, revealing its unique integrated …

Physiological Function Of Fus: An Rna Binding Protein In Motor Neuron Disease, Liuqing Yang

Theses and Dissertations--Molecular and Cellular Biochemistry

FUS is an RNA binding protein implicated in the motor neuron disease— amyotrophic lateral sclerosis (ALS, also called Lou Gehrig’s disease). ALS is a fatal neurodegenerative disease characterized by progressive motor neuron death. Mutations in the FUS gene cause about 4% of familial ALS (FUS ALS). Mutated FUS protein mislocalizes from the motor neuron nucleus to the cytoplasm and forms inclusions in the cytoplasm. It is unclear how FUS mislocalization induces motor neuron dysfunction and degeneration. This dissertation research was designed to investigate the physiological functions of FUS in the nucleus, with a purpose to shed light on the pathogenesis …

Cross-Talk Between The Tumor Suppressors Par-4 And P53, Tripti Shrestha Bhattarai

Theses and Dissertations--Toxicology and Cancer Biology

This work describes the fascinating interplay between two tumor suppressors Prostate apoptosis response-4 (Par-4) and p53. The guardian of the genome, p53, is frequently mutated in human cancers, and may contribute to therapeutic resistance. However, p53 is intact and functional in normal tissues, and we observed that specific activation of p53 in normal fibroblasts could induce apoptosis selectively in p53-deficient cancer cells. This paracrine apoptotic effect was executed by Par-4 secreted in response to p53 activation. Accordingly, activation of p53 in wild-type mice, but not in p53^-/- or Par-4^-/- mice, caused systemic elevation of Par-4 that induced apoptosis …

The Role Of Phlpp In Pancreatic Cancer, Alena J. Smith

Theses and Dissertations--Molecular and Cellular Biochemistry

Medicine has come a long way in recent years with reliable treatments for many cancers. Pancreatic ductal adenocarcinoma (PDAC) has very few treatment options available. PDAC has a dismal 5 year survival rate of 4% and a median survival span of 6 months from point of diagnosis; with a high rate of chemotherapy and radiation resistance. A better understanding of the molecular events leading to cancer progression is needed in order to improve the treatment and prognosis of PDAC patients. We begin to elucidate the functional importance of PHLPP on suppressing progression and metastasis of PDAC. PHLPP belongs to a …

Adp-Ribosylation Factor 6 (Arf6) Regulates Integrin Αiibβ3 Trafficking, Platelet Spreading, And Clot Retraction, Yunjie Huang

Theses and Dissertations--Molecular and Cellular Biochemistry

Endocytic trafficking of platelet surface receptors plays a role in the accumulation of granule cargo (i.e. fibrinogen and VEGF) and thus could contribute to hemostasis, angiogenesis, or inflammation. However, the mechanisms of platelet endocytosis are poorly understood. The small GTP-binding protein, ADP-ribosylation factor 6 (Arf6), regulates integrin trafficking in nucleated cells; therefore, we posited that Arf6 functions similarly in platelets. To address this, we generated platelet-specific, Arf6 knockout mice. Arf6^-/- platelets had a storage defect for fibrinogen but not other cargo, implying Arf6’s role in integrin αIIbβ3 trafficking. Additionally, platelets from Arf6^-/- mice injected with biotinylated-fibrinogen, showed …

Physical Interactions Between Neuropilin And Vegfrs, Integrins In Regulating Endothelial Cell Functions, Xiaobo Li

Theses and Dissertations--Molecular and Cellular Biochemistry

The neuropilin (Nrp) family consists of multifunctional cell surface receptors with critical roles in a number of different cell and tissue types. A core aspect of Nrp function is ligand-dependent cellular adhesion and migration, where it controls the multistep process of cellular motility through integration of ligand binding, receptor coupling and signaling via the coordinated action of its extracellular and intracellular domains. While Nrp regulates cellular adhesion and motility in the cardiovascular and nervous systems under physiological conditions, the emerging pathological role of Nrp in tumor cell migration and metastasis has been identified and provides motivation for continued efforts toward …

Chemoenzymatic Studies To Enhance The Chemical Space Of Natural Products, Jhong-Min Chen

Theses and Dissertations--Pharmacy

Natural products provide some of the most potent anticancer agents and offer a template for new drug design or improvement with the advantage of an enormous chemical space. The overall goal of this thesis research is to enhance the chemical space of two natural products in order to generate novel drugs with better in vivo bioactivities than the original natural products.

Polycarcin V (PV) is a gilvocarcin-type antitumor agent with similar structure and comparable bioactivity with the principle compound of this group, gilvocarcin V (GV). Modest modifications of the polyketide-derived tetracyclic core of GV had been accomplished, but the most …

Up Regulation Of Heat Shock Protein 70b (Hsp70b) And Ssa1 In Chlamydomonas Reinhardtii Via Hsp70a-Rbcs2 And Psad Promoter, B. Kirtley Amos

Theses and Dissertations--Biosystems and Agricultural Engineering

Fabrication of effective algae cultivation systems adjacent to coal-fired power plants to fixate waste CO₂ would represent a sizable step towards achieving a carbon neutral energy cycle. However, emission gas would elevate the algal cultivation system temperature and decreases its pH without expensive preprocessing. Increased temperature and acidity constitutes a profound stress on the algae. Although stressed algae produce heat shock proteins (HSPs) that promote protein folding and protect against stress, the ordinary biological response is insufficient to protect against coal flue gas. Experimental upregulation of HSPs could make algae respond to the stress caused by high temperatures and …

Nanoparticle Behavior In Biological Gels And Biofluids: The Impact Of Interactions With Charged Biogels And The Formation Of Protein Coronas On Nanoparticles, Xiaolu Zhang

Theses and Dissertations--Chemistry

With the rapid growth of nanotechnology, situations where nanomaterials will interact with biological systems will unquestionably grow. Therefore, it is increasingly understood that interactions between nanomaterials and biological environments will play an essential role in nanomedicine. Biological polymer networks, including mucus and the extracellular matrix, serve as a filter for the exchange of molecules and nanoparticles. Such polymer networks are complex and heterogeneous hydrogel environments that regulate transport processes through finely tuned particle-network interactions. In chapters 3 and 4, we investigate the role of electrostatics on the basic mechanisms governing the diffusion of charged molecules inside model polymer networks by …

Beryllium Nitrate Supports Fibroblast Migration As An Essential Component Of Skin And Limb Regeneration In Axolotls, Adam Boyd Cook

Theses and Dissertations--Biology

Tissue regeneration in salamanders is a robust process that is not easily interrupted or altered. Therefore, inhibiting regeneration provides a means to interrogate the underlying cellular and molecular mechanisms regulating this complex event. Here we show that application of a relatively low concentration of beryllium nitrate solution (100mM) causes a delay in skin regeneration and severely alters normal limb regeneration. We provide evidence showing a beryllium-induced reduction in dermal fibroblast migration in vivo and in vitro. We link this phenomenon to delayed regeneration of the skin and abnormal blastema formation resulting in limb patterning defects during regeneration. Though our …