Biochemistry, Biophysics, and Structural Biology Commons^™

Biochemical Characterization Of The Dimerization Domain Of Purine-Rich Element Binding Protein B: An Essential Subdomain Mediating The Repression Of Smooth Muscle Alpha Actin Gene Expression, Lauren Ferris

Graduate College Dissertations and Theses

A number of physiologic processes require the expression of smooth muscle alpha actin (SMαA) to mediate cellular contraction. Stable expression of SMαA in differentiated vascular smooth muscle cells is associated with a contractile phenotype that is essential for regulation of blood flow and pressure. The transient expression of SMαA in myofibroblasts during wound repair facilitates wound closure. Hence, it is no surprise that dysregulation of SMαA gene expression in both cell types can have pathological consequences. Indeed, aberrant SMαA gene regulation has been implicated in diseases such as atherosclerosis and fibrosis. Therefore, a better understanding of the molecular mechanisms that …

The A-Site In The Pkg Iα Regulatory Domain Controls Both Cgmp- And Oxidative-Dependent Activation, Jessica Lynne Sheehe

Graduate College Dissertations and Theses

The type Iα cGMP-dependent protein kinase (PKG Iα) is an essential regulator of vascular tone and systemic blood pressure. Located in the smooth muscle of resistance vessels, PKG Iα stimulates vasodilation through the phosphorylation of multiple intracellular substrates. Its primary regulator is the small molecule, 3',5'-cyclic guanosine monophosphate (cGMP); however, the Iα isoform can also be activated by oxidation. Despite the established physiological importance of PKG Iα, the structural underpinnings of these two activation mechanisms are largely unknown.

The work presented in this dissertation demonstrates the importance of the cGMP-binding domain A (CBD-A) in regulating both of these mechanisms of …

Single Molecule Imaging Reveals Tau Structure And Function On The Microtubule Surface, Jamie Stern

Graduate College Dissertations and Theses

Neurons are among the most highly polarized cells in the human body. This polarization allows the neuron to participate in the transfer of chemical and electrical signals which are crucial to the survival of the organism. As part of polarization, each neuron develops a dendritic arbor and an axon. To ensure the survival of the cell, materials synthesized in the cell body must be trafficked through the axon for delivery throughout ultimately ending at the synaptic termini. The bulk of this cargo transport is microtubule-based fast axonal transport which is molecular motor mediated and tightly regulated though many pathways. Motor …

Cargo Transport By Myosin Va Molecular Motors Within Three-Dimensional In Vitro Models Of The Intracellular Actin Cytoskeletal Network, Andrew Thomas Lombardo

Graduate College Dissertations and Theses

Intracellular cargo transport involves the movement of critical cellular components (e.g. vesicles, organelles, mRNA, chromosomes) along cytoskeletal tracks by tiny molecular motors. Myosin Va motors have been demonstrated to play a vital role in the transport of cargos destined for the cell membrane by navigating their cargos through the three-dimensional actin networks of the cell. Transport of cargo through these networks presents many challenges, including directional and physical obstacles which teams of myosin Va-bound to a single cargo must overcome. Specifically, myosin Va motors are presented with numerous actin-actin intersections and dense networks of filaments which can act as a …

Secondary Functions And Novel Inhibitors Of Aminoacyl-Trna Synthetases, Patrick Wiencek

Graduate College Dissertations and Theses

The aminoacyl-tRNA synthetases are a family of enzymes involved in the process of translation, more specifically, ligating amino acids to their cognate tRNA molecules. Recent evidence suggests that aminoacyl-tRNA synthetases are capable of aminoacylating proteins, some of which are involved in the autophagy pathway. Here, we test the conditions under which E. coli and human threonyl-tRNA synthetases, as well as hisidyl-tRNA synthetase aminoacylate themselves. These reactions are ATP dependent, stimulated by Mg2+, and are inhibited by increasing cognate tRNA concentrations. These data represent the foundation for future aminoacylation experiments, specifically delving into the relationship between the autophagy pathway and the …

Selenium In Thioredoxin Reductase: Resistance To Oxidative Inactivation, Oxidation States, And Reversibility Of Chemical Reactions, Drew Barber

Graduate College Dissertations and Theses

Selenium is a required trace element which was originally discovered by the Swedish chemist Jons Jacob Berzelius in 1817. It was initially believed to be a toxin as it was identified as being the cause of hoof maladies and excessive hair loss in horses that feed upon plants with high selenium content. It wasn’t until 1957 that the potential contributions of selenium to physiology were first demonstrated. Selenium is now known to play a critical role in the maintenance of human health. Interestingly, unlike other trace metals/semi-metals, selenium is directly incorporated into proteins in the form of the amino acid …

Methylation Controlled J Protein Is A Master Regulator Of Mitochondrial Metabolism, Devin Pierre Champagne

Graduate College Dissertations and Theses

Methylation controlled J protein (MCJ) is a negative regulator of mitochondrial metabolism that has a substantial impact on overall cell metabolism and function. MCJ is highly expressed by naïve CD8+ T cells, however its role in their immune effector functions was unknown. In this dissertation, it will be demonstrated that MCJ restricts the mitochondrial metabolism of CD8+ T cells, in part by reducing respiratory supercomplex formation. MCJ deficiency enhances the immune effector functions and memory responses of CD8+ T cells in a mitochondrial ATP dependent manner. As a consequence, protection to influenza virus infection is substantially improved. Reduced expression of …

Detection Of The Lung Environment By Multi-Drug Resistant Gram-Negative Bacterial Pathogens, Graham Geier Willsey

Graduate College Dissertations and Theses

Nosocomial lung infections are a growing concern in the United States, with more than 300,000 cases reported annually. More than 30 % of which are caused by the Gram-negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae. Similarly, Gram-negative bacteria establish chronic infections in individuals with cystic fibrosis (CF) that are difficult or impossible to eradicate.P. aeruginosa has historically been one of the most prevalent pathogens of adults with CF. However, as antipseudomonal therapy has improved, more antibiotic resistant species have taken hold, including Stenotrophomonas maltophilia, which now colonizes more than 10 % of individuals with CF. Regardless of …

Evidence For The Involvement Of Runx1 And Runx2 In Maintenance Of The Breast Cancer Stem Cell Phenotype, Mark Fitzgerald

Graduate College Dissertations and Theses

In the United States, metastatic breast cancer kills approximately 40,000 women and 400 men annually, and approximately 200,000 new cases of breast cancer are diagnosed each year. Worldwide, breast cancer is the leading cause of cancer deaths among women. Despite advances in the detection and treatment of metastatic breast cancer, mortality rates from this disease remain high because the fact is that once metastatic, it is virtually incurable. It is widely accepted that a major reason breast cancer continues to exhibit recurrence after remission is that current therapies are insufficient for targeting and eliminating therapy-resistant cancer cells. Emerging research has …

21st Century Approaches To Addressing Childhood Diarrhea In Low And Middle-Income Countries: Zinc As A Cornerstone Of New Prevention Strategies, Elizabeth Ross Colgate

Graduate College Dissertations and Theses

During the 20th century, significant strides were made in curtailing the burden of childhood diarrhea, including advances in vaccine research, the advent of antibiotics, improved water and sanitation, and expanded access to health information across the globe. Despite this progress, today diarrhea ranks second only to pneumonia as a leading cause of mortality in children under five years, with a disproportionate burden of 90% of diarrheal deaths in South Asia and Sub-Saharan Africa. Additionally, substantial morbidity due to diarrhea persists in young children, with more than 45 million disability-adjusted life years (DALYs) lost due to diarrhea in 2015. Long-term consequences …

A Proximity-Dependent Biotin Labeling Based Screen For Protein Kinase A Anchoring Proteins Within Focal Adhesion Complexes, Hannah Naughton

Graduate College Dissertations and Theses

Protein kinase A (PKA) regulates a diverse array of cellular activities including metabolism, differentiation, actomyosin contractility, and migration. The multifunctionality of this ubiquitous enzyme is achieved, in part, through subcellular targeting mediated by the A Kinase Anchoring Proteins (AKAP) family of proteins. AKAPs serve as scaffolding proteins that localize PKA to various cellular compartments and bring together specific targets and modulators of PKA activity.

The importance of spatially restricted PKA signaling is particularly apparent in the context of cell motility. It has been observed that both anchoring through AKAPs and the subsequent localized activation of PKA at the leading edge …

Diversification Of Muroid Rodents Driven By The Late Miocene Global Cooling, Nelish Pradhan

Graduate College Dissertations and Theses

Late Miocene, 8 to 6 million years ago (Ma), climatic changes brought about dramatic floral and faunal changes. Cooler and drier climates that prevailed in the Late Miocene led to expansion of grasslands and retreat of forests at a global scale. Palaeogeographic studies suggest a global vegetation change causing an abrupt increase in C4 plant biomass while C3 biomass decreased between 8 and 6 Ma. Subsequent cycles of cooler and drier climatic conditions during the Mid-Pliocene (3.5–3 Ma) and Pleistocene (2.8–2.5; 1.8–1.6; 1.0–0.8 Ma) also caused forests to retreat into isolated refugia which played an important role in events that …