Molecular Biology Commons^™

Conserved Glycine Residues Control Transient Helicity And Disorder In The Cold Regulated Protein, Cor15a, Oluwakemi Sowemimo

USF Tampa Graduate Theses and Dissertations

COR15A is a cold regulated disordered protein from Arabidopsis thaliana that contributes to freezing tolerance in plants by protecting membranes. It belongs to the (LEA) Late Embryogenesis Abundant group of proteins that accumulate during the later stage of seed development and are expressed in various parts of the plant. During freezing-induced cellular dehydration, COR15A transitions from a disordered structure to a mostly α-helical structure that binds and stabilizes chloroplast membranes when cells dehydrate due to freezing. We hypothesize that increasing the transient α-helicity of COR15A under normal conditions will increase its ability to bind and protect chloroplast membranes when cells …

Biochemical And Proteomic Approaches To Determine The Impact Level Of Each Step Of The Supply Chain On Tomato Fruit Quality, Robert T. Madden

USF Tampa Graduate Theses and Dissertations

Fresh fruits and vegetables (FFVs) are the most frequently wasted foods because of their perishability and handling requirements. However, there is a lack of information on how much each step of the supply chain impacts FFVs quality, particularly on tomatoes, and what measures need to be taken for an immediate and effective impact on waste reduction. There is also no information on how the supply chain affects the proteome of the tomato and what proteins are differentially regulated by the most impactful steps of the supply chain. The objectives of the work presented on this thesis were to evaluate the …

The Drosophila Neuroblasts: A Model System For Human Ribosomopathies, Sonu Shrestha Baral

LSU Doctoral Dissertations

This dissertation describes the use of Drosophila neuroblasts (NBs) to model human ribosomopathies; the overall goal is to understand why specific stem cell and progenitor cell populations are the primary targets in nucleolar stress as seen in the ribosomopathies. Chapter 1 provides an overview of relevant literature. Chapter 2 describes nucleolar stress in Drosophila neuroblasts as a model for human ribosomopathies. For this, we induce nucleolar stress by using the UAS-GAL4 system to express RNAi that depletes Nopp140 transcripts, and we also employ homozygous, CRISPR-Cas9-generated Nopp140 gene disruptions with a systemic null phenotype (Nopp140-/-). Embryonic lethality was observed …

Integrated Molecular Characterization Of Lung Adenocarcinoma With Implications For Immunotherapy, Nicholas T. Gimbrone

USF Tampa Graduate Theses and Dissertations

This dissertation covers a variety of the genetic and molecular abnormalities of lung adenocarcinoma with an emphasis on STK11 loss and its implications on immunotherapy response. Given that lung cancer is the leading cancer killer, novel therapies are in great demand. In particular, immunotherapy has shown some of the most promise in the last decade but remains limited due to nearly 80% of patients not significantly responding. This dissertation aims to molecularly characterize lung adenocarcinoma while attempting to explain the reason why patients with STK11 loss do not respond to immunotherapy.

In the first chapter we discuss the relationship between …

Deletion Of Mgr2p Affects The Gating Behavior Of The Tim23 Complex, Oygul Mirzalieva, Shinhye Jeon, Kevin Damri, Ruth Hartke, Layla Drwesh, Keren Demishtein-Zohary, Abdussalam Azem, Cory D. Dunn, Pablo M. Peixoto

Publications and Research

The TIM23 complex is a hub for translocation of preproteins into or across the mitochondrial inner membrane. This dual sorting mechanism is currently being investigated, and in yeast appears to be regulated by a recently discovered subunit, the Mgr2 protein. Deletion of Mgr2p has been found to delay protein translocation into the matrix and accumulation in the inner membrane. This result and other findings suggested that Mgr2p controls the lateral release of inner membrane proteins harboring a stop-transfer signal that follows an N-terminal amino acid signal. However, the mechanism of lateral release is unknown. Here, we used patch clamp electrophysiology …

Insights Into The Ribosomal, Extra-Ribosomal And Developmental Role Of Rp L13a In Mammalian Model, Ravinder Kour

ETD Archive

Ribosomal protein L13a plays an extra-ribosomal function in translational silencing of GAIT (IFN-gamma-activated inhibitor of translation) element bearing mRNAs encoding inflammatory proteins but the underlying molecular mechanism of translational silencing and ribosomal incorporation of L13a remains poorly understood. Also, our laboratory showed that L13a acts as a physiological defense against uncontrolled inflammation in macrophage-specific knockout (KO) mice. However, the consequence of a total knockout of L13a in mammals remains unexplored. Therefore, our current study is focused on (i) identifying the amino acid residue(s) of L13a essential for incorporation and translational silencing of target mRNAs and (ii) studying the consequences of …

The Role Of The Cell-Surface Protease Tmprss13 In Colorectal Cancer, Fausto Alexander Varela

Wayne State University Dissertations

Colorectal cancer (CRC) is one of the most common and deadly cancers in both men and women in the United States. Extracellular proteolysis is often dysregulated in cancer including (CRC), resulting in degradation of extracellular matrix, as well as cleavage, processing, or shedding of cell adhesion molecules, growth factors, and cytokines. Several members of the type II transmembrane serine protease (TTSP) family have been shown to play critical roles in cancer progression; however, many family members have not yet been characterized in malignancy. We identified TMPRSS13 transcript to be upregulated in CRC compared to normal colon. This increase was confirmed …

Cornus Officinalis Significantly Improves Oxidative Capacity And Promotes The Calcium-Dependent Transcription Factor, Nfatc2, In Human 1.1b4 Pancreatic Cell Line, Arielle Sharp, Alexis Coiner, Brant Burkhardt

Molecular Biosciences Faculty Publications

Type 1 diabetes (T1D) is an autoimmune disease resulting in the destruction of pancreatic β cells (β-cells) and subsequent loss of insulin production. The only treatment for T1D is using exogenous insulin coupled with continual glucose monitoring following significant autoimmune destruction of β-cells. Novel interventional therapies are needed that can preserve and protect existing pancreatic β cells in individuals with early identified T1D autoimmunity. Our initial in-vitro evidence indicates Cornus officinalis (CO) may be able to serve in this function. What sets ethnopharmacology apart from conventional medicine is the simultaneous targeting of multiple mechanisms using a single herb due to …

Structural Basis Of Phosphatidylcholine Recognition By The C2–Domain Of Cytosolic Phospholipase A,2Α, Yoshinori Hirano, Yong-Guang Gao, Daniel J. Stephenson, Ngoc T. Vu, Lucy Malinina, Dhirendra K. Simanshu, Charles E. Chalfant, Dinshaw J. Patel, Rhoderick E. Brown

Molecular Biosciences Faculty Publications

Ca²⁺-stimulated translocation of cytosolic phospholipase A2α (cPLA2α) to the Golgi induces arachidonic acid production, the rate-limiting step in pro-inflammatory eicosanoid synthesis. Structural insights into the cPLA2α preference for phosphatidylcholine (PC)-enriched membranes have remained elusive. Here, we report the structure of the cPLA2α C2-domain (at 2.2 Å resolution), which contains bound 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) and Ca2+ ions. Two Ca2+ are complexed at previously reported locations in the lipid-free C2-domain. One of these Ca2+ions, along with a third Ca2+, bridges the C2-domain to the DHPC phosphate group, which also interacts with Asn65. Tyr96 plays a key role in lipid …

Conserved Glycines Control Disorder And Function In The Cold-Regulated Protein, Cor15a, Oluwakemi T. Sowemimo, Patrick Knox-Brown, Wade M. Borcherds, Tobias Rindfleisch, Anja Thalhammer, Gary W. Daughdrill

Molecular Biosciences Faculty Publications

Cold-regulated (COR) 15A is an intrinsically disordered protein (IDP) from Arabidopsis thaliana important for freezing tolerance. During freezing-induced cellular dehydration, COR15A transitions from a disordered to mostly α-helical structure. We tested whether mutations that increase the helicity of COR15A also increase its protective function. Conserved glycine residues were identified and mutated to alanine. Nuclear magnetic resonance (NMR) spectroscopy was used to identify residue-specific changes in helicity for wildtype (WT) COR15A and the mutants. Circular dichroism (CD) spectroscopy was used to monitor the coil–helix transition in response to increasing concentrations of trifluoroethanol (TFE) and ethylene glycol. The impact of the COR15A …

Functional Inhibition Of Acid Sphingomyelinase Disrupts Infection By Intracellular Bacterial Pathogens, Chelsea L. Cockburn, Ryan S. Green, Sheela R. Damle, Rebecca K. Martin, Naomi N. Ghahrai, Punsiri M. Colonne, Marissa S. Fullerton, Daniel H. Conrad, Charles E. Chalfant, Daniel E. Voth, Elizabeth A. Rucks, Stacey D. Gilk, Jason A. Carlyon

Molecular Biosciences Faculty Publications

Intracellular bacteria that live in host cell–derived vacuoles are significant causes of human disease. Parasitism of low-density lipoprotein (LDL) cholesterol is essential for many vacuole-adapted bacteria. Acid sphingomyelinase (ASM) influences LDL cholesterol egress from the lysosome. Using functional inhibitors of ASM (FIASMAs), we show that ASM activity is key for infection cycles of vacuole-adapted bacteria that target cholesterol trafficking—Anaplasma phagocytophilum, Coxiella burnetii, Chlamydia trachomatis, and Chlamydia pneumoniae. Vacuole maturation, replication, and infectious progeny generation by A. phagocytophilum, which exclusively hijacks LDL cholesterol, are halted and C. burnetii, for which lysosomal cholesterol accumulation is bactericidal, …

Functional Analysis Of The Replication Fork Proteome Identifies Bet Proteins As Pcna Regulators, Sarah R. Wessel, Kareem N. Mohni, Jessica W. Luzwick, Huzefa Dungrawala, David Cortez

Molecular Biosciences Faculty Publications

Identifying proteins that function at replication forks is essential to understanding DNA replication, chromatin assembly, and replication-coupled DNA repair mechanisms. Combining quantitative mass spectrometry in multiple cell types with stringent statistical cutoffs, we generated a high-confidence catalog of 593 proteins that are enriched at replication forks and nascent chromatin. Loss-of-function genetic analyses indicate that 85% yield phenotypes that are consistent with activities in DNA and chromatin replication or already have described functions in these processes. We illustrate the value of this resource by identifying activities of the BET family proteins BRD2, BRD3, and BRD4 in controlling DNA replication. These proteins …

P53 Phosphomimetics Preserve Transient Secondary Structure But Reduce Binding To Mdm2 And Mdmx, Robin Levy, Emily Gregory, Wade Borcherds, Gary W. Daughdrill

Molecular Biosciences Faculty Publications

The disordered p53 transactivation domain (p53TAD) contains specific levels of transient helical secondary structure that are necessary for its binding to the negative regulators, mouse double minute 2 (Mdm2) and MdmX. The interactions of p53 with Mdm2 and MdmX are also modulated by posttranslational modifications (PTMs) of p53TAD including phosphorylation at S15, T18 and S20 that inhibits p53-Mdm2 binding. It is unclear whether the levels of transient secondary structure in p53TAD are changed by phosphorylation or other PTMs. We used phosphomimetic mutants to determine if adding a negative charge at positions 15 and 18 has any effect on the transient …

Identification Of Proteins Interacting With Zebrafish Miro Orthologs In The Yeast Two-Hybrid System, Yiran Tao

Honors Program Theses

The motility of mitochondria is required for providing energy and maintaining basic cellular functions in neurons. Mitochondrial Rho GTPase (Miro) is an essential component of the mitochondrial trafficking machinery, a protein complex that anchors mitochondria to the microtubule motor protein for long-distance transport. As a protein localizing to the mitochondrial outer membrane, Miro regulates the morphology and the motility of mitochondria. Upon mitochondrial depolarization, the PINK1/Parkin pathway is activated to arrest mitochondrial movement by targeting Miro for phosphorylation and ubiquitination in a calcium-sensitive manner. However, it remains unclear what effects the PINK1-dependent phosphorylation has on the structure and binding properties …

The Otud5–Ubr5 Complex Regulates Fact-Mediated Transcription At Damaged Chromatin, Angelo De Vivo, University Of South Florida, Jose Yegres, Jeonghyeon Kim, Sylvia Emly, Younghoon Kee

Molecular Biosciences Faculty Publications

Timely stalling and resumption of RNA polymerases at damaged chromatin are actively regulated processes. Prior work showed an importance of FACT histone chaperone in such process. Here we provide a new role of OTUD5 deubiquitinase in the FACT-dependent process. Through a DUB RNAi screen, we found OTUD5 as a specific stabilizer of the UBR5 E3 ligase. OTUD5 localizes to DNA double strand breaks (DSBs), interacts with UBR5 and represses the RNA Pol II elongation and RNA synthesis. OTUD5 co-localizes and interacts with the FACT component SPT16 and antagonizes the histone H2A deposition at DSB lesions. OTUD5 interacts with UBR5 and …

Of Donuts And Promo : In Silico Approaches To Identification Of Transcriptional Regulators Of Salivary Acinar Differentiation, Connor Cillian Duffy

Legacy Theses & Dissertations (2009 - 2024)

The salivary gland is an organ often taken for granted by most people. However, its proper function is essential for several everyday activities, such as speaking, swallowing, and tasting. As such, impaired salivary gland function, such as that caused by Sjögren’s Syndrome or radiotherapy for head and neck cancers, can lead to a significantly reduced quality of life. The cells that produce saliva in salivary glands are known as acinar cells, which arise from proacinar cells generated during embryonic development. As such, in studying the promoter regions of proacinar and acinar genes, it may be possible to identify common transcription …

Mechanisms Of Trinucleotide Repeat Instability During Dna Synthesis, Kara Y. Chan

Theses and Dissertations--Toxicology and Cancer Biology

Genomic instability, in the form of gene mutations, insertions/deletions, and gene amplifications, is one of the hallmarks in many types of cancers and other inheritable genetic disorders. Trinucleotide repeat (TNR) disorders, such as Huntington’s disease (HD) and Myotonic dystrophy (DM) can be inherited and repeats may be extended through subsequent generations. However, it is not clear how the CAG repeats expand through generations in HD. Two possible repeat expansion mechanisms include: 1) polymerase mediated repeat extension; 2) persistent TNR hairpin structure formation persisting in the genome resulting in expansion after subsequent cell division. Recent in vitro studies suggested that a …

Mutations Of Fus Cause Aggregation Of Rna Binding Proteins, Disruptions In Protein Synthesis, And Dysregulation Of Nonsense Mediated Decay, Marisa Elizabeth Kamelgarn

Theses and Dissertations--Toxicology and Cancer Biology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron death and subsequent muscle atrophy. Approximately 15% of ALS cases are inheritable, and mutations in the Fused in Sarcoma (FUS) gene contribute to approximately 5% of these cases, as well as about 2% of sporadic cases. FUS performs a diverse set of cellular functions, including being a major regulator of RNA metabolism. FUS undergoes liquid- liquid phase transition in vitro, allowing for its participation in stress granules and RNA transport granules. Phase transition also contributes to the formation of cytoplasmic inclusions found in the …

The Balance Between Prostaglandin E2 Ep3 And Ep4 Receptors Determines Severity Of Cardiac Damage In Myocardial Infarction And An Angiotensin Ii-Induced Model Of Hypertension, Timothy Dean Bryson

Wayne State University Dissertations

According to the center for disease control about 610,000 people die every year in the United States from heart disease, of which, coronary heart disease is the most common form. One major risk factor for heart attack is hypertension, which affects nearly half of all Americans [472, 473]. PGE2 plays an important role in regulating cardiovascular function and mediating inflammation, both of which contribute to the development of hypertension and/or heart disease. Prostaglandin E2 can act as a vasodilator or vasoconstrictor depending on which of its receptor subtypes are activated.

In general, activation of the EP1 and EP3 receptors is …

Characterizing Chromosomal Aberrations In Cells Deficient For Both Atm And Msh2, Yeliz Inalman

Dissertations and Theses

Ataxia telangiectasia mutated (ATM) and mutS homologue 2 (MSH2) are important DNA repair proteins that participate in DNA repair pathways to maintain genomic integrity. Mice deficient for ATM and MSH2 mice are viable. However, ATM^-/- mice show growth retardation, neurological defects, and spontaneous lymphomagenesis. MSH2^-/- mice suffer from aggressive lymphoid tumors between two to five months of age and have increased microsatellite instability, which predisposes MSH2^-/- mice to carcinomas. However, mice deficient in both ATM and MSH2 are unable to survive beyond postnatal day 21 (P21). The observed lethality in ATM^-/-MSH2^-/- mice may result …

The Dna Dependent Protein Kinase Catalytic Subunit Maintains Genomic Stability, Brandon Lee Sklavanitis

Graduate Research Theses & Dissertations

GBM is the most common CNS derived malignancy diagnosed each year. The median survival time to date is between 14.6 to 16.7 months for patients suffering from the disease. Clinical trials and research has yet to yield a breakthrough treatment. The invasive nature of GBM to surrounding tissue typically poses a challenge for complete surgical resection of the tumor, and radiotherapy remains a predominant treatment modality. The NHEJ pathway is main repair pathway responsible for repairing lethal radiation damage. As a result, this study used the CRISPR-Cas9 system to genetically engineer two GBM cell lines lacking expression of an essential …

Comparative Tumorigenic Amino Acid Starvation And Integrated Stress Responses In Epithelial Vs. Mesenchymal Hcc Cells With Asct2 Or Lat1 Transporter Knockouts, Stephanie Lois Cooper Woodin

Graduate Research Theses & Dissertations

The previously established roles of the amino acid glutamine have recently been expanded to include not only protein and nucleotide synthesis, as well as contributing significantly to energy production via mitochondrial hydrolysis of glutamine to glutamate, but also the role of this molecule in the reductive carboxylation of α-ketoglutarate resulting in carbon atoms used in cell membrane biosynthesis. Additionally, glutamine participates in maintaining glutathione homeostasis as well as regulation of anabolic signaling. Given its central role in anabolic processes, glutamine is preferentially transported into human cancer cells at a significant rate as compared to normal cells. This distinction has prompted …

Regulation Of The Long Non-Coding Rna Fam83h-As1 By Human Papillomavirus In Cervical Cancer, Jamie Ann Barr Ph.D.

Graduate Theses, Dissertations, and Problem Reports (ETD)

Non-coding RNAs (NcRNAs), such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), have been found to be involved in a variety of critical biological processes, and dysregulation of ncRNAs have been involved with several human diseases including cancer.

High-risk human papillomavirus (HPV) infection is one of the first events in the process of carcinogenesis in cervical and a subset of head and neck cancers. The expression of the viral oncoproteins E6 and E7 is essential in this process by inactivating the tumor suppressor proteins p53 and Rb, respectively, in addition to their interactions with other host proteins and regulation of …

Eralpha Isoforms Modulate The Tumorigenicity Of 24r,25(Oh)2d3 In Estrogen-Responsive Cancer, Anjali Verma

Theses and Dissertations

Over 200,000 cases of breast cancer are diagnosed every year. Nearly 20% of these patients supplement their diets with some form of vitamin D. This high frequency of vitamin D supplement use may be due in part to research suggesting that cancer patients with higher serum vitamin D₃ levels have better prognoses than patients with low serum vitamin D_3. However, double-blind clinical trials on the efficacy of vitamin D₃ supplementation in breast cancer have been inconclusive. A recent meta-analysis showed evidence of reduced cancer recurrence in patients taking vitamin D₃ supplements who had ‘estrogen receptor positive’ …

Delineation Of New Mechanisms Of Dna Double Strand Break Repair, Songli Zhu

Theses & Dissertations

DNA damage is frequently induced in cells by both endogenous and exogenous agents. DNA damage, particular double strand breaks (DSBs) may lead to genomic instability, and the progression of cancer, aging, neurodegeneration, and other human diseases. The cell employs two major DSB repair pathways, including homologous recombination (HR) and Non-homologous end joining (NHEJ), but the detailed mechanisms of DSB repair remain to be further revealed.

In the first part of this study, we characterized a plasmid-based assay to investigate NHEJ repair in Xenopus egg extracts. Our data argued for a preference for the precise repair by the NHEJ machinery and …

Intra- And Inter-Molecular Signaling In A Cardiac Connexin: Role Of Cytoplasmic Domain Dimerization And Phosphorylation, Andrew J. Trease

Theses & Dissertations

As critical mediators of cell-to-cell communication, gap junctions (GJs) are comprised of membrane channels that directly link the cytoplasm of adjacent coupled cells thereby allowing for the passage of ions, small metabolites, and secondary messengers. Each channel is formed by the apposition of two connexons from adjacent cells, each composed of six connexin (Cx) proteins. Each GJ channel functions to promote signal propagation and synchronization of cells and tissues in organs. Furthermore, GJs are essential for proper propagation of cardiac action potentials from one cell to the next, leading to the coordinated contraction and relaxation of heart muscle powering circulation. …

Actinomycin D And Telmisartan Combination Therapy Targets Lung Cancer Stem Cells, Ryan Green

USF Tampa Graduate Theses and Dissertations

The failure of lung cancer treatments has been attributed partly to the development of drug resistance, however the underlying cellular and molecular mechanisms are poorly understood. It has been suggested that a very small group of specific cells within the heterogeneous tumors, cancer initiating stem cells (CSC), develop resistance to treatment, survive and later initiate the growth of new tumors. Due to their pivotal role in maintenance and relapse of tumors following the acquisition of drug resistance, we reasoned that novel drugs targeting cancer cells and CSC might provide the most effective treatments, if not a cure. To this end, …

Investigating The Roles Of Fucosylation And Calcium Signaling In Melanoma Invasion, Tyler S. Keeley

USF Tampa Graduate Theses and Dissertations

Melanoma is the deadliest form of skin cancer. Prognosis for early stage melanoma patients is excellent, and surgery is often curative for these patients. However, once patients have presented with invasive disease, the average 5-year survival rate drops significantly from over 90% to between 10 and 15%. Several therapies have been developed to target a commonly mutated oncogene BRAF, or its downstream effectors. Unfortunately, while these treatments show robust initial response, most patients relapse within a year. Moreover, therapy-resistant tumors are often more invasive and metastatic. Therefore, it is important to investigate the molecular mechanisms underlying melanoma invasion and metastasis, …

Combined High-Speed Single Particle Tracking Of Membrane Proteins And Super-Resolution Of Membrane-Associated Structures, Hanieh Mazloom Farsibaf, Keith A. Lidke

Shared Knowledge Conference

Many experiments have shown that the diffusive motion of lipids and membrane proteins are slower on the cell surface than those in artificial lipid bilayers or blebs. One hypothesis that may partially explain this mystery is the effect of the cytoskeleton structures on the protein dynamics. A model proposed by Kusumi [1] is the Fence-Picket Model which describes the cell membrane as a set of compartment regions, each ~ 10 to 200 nm in size, created by direct or indirect interaction of lipids and proteins with actin filaments just below the membrane. To test this hypothesis, we have assembled a …

Iron-Dependent Cleavage Of Ribosomal Rna During Oxidative Stress In The Yeast Saccharomyces Cerevisiae, Jessica A Zinskie, Arnab Ghosh, Brandon M Trainor, Daniel Shedlovskiy, Dimitri G Pestov, Natalia Shcherbik

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Stress-induced strand breaks in rRNA have been observed in many organisms, but the mechanisms by which they originate are not well-understood. Here we show that a chemical rather than an enzymatic mechanism initiates rRNA cleavages during oxidative stress in yeast (Saccharomyces cerevisiae). We used cells lacking the mitochondrial glutaredoxin Grx5 to demonstrate that oxidant-induced cleavage formation in 25S rRNA correlates with intracellular iron levels. Sequestering free iron by chemical or genetic means decreased the extent of rRNA degradation and relieved the hypersensitivity of grx5Δ cells to the oxidants. Importantly, subjecting purified ribosomes to an in vitro iron/ascorbate …