Biochemistry, Biophysics, and Structural Biology Commons^™

From Geometry To Recognition: A Quantitative Framework For Tcr-Pmhc Structural Analysis In The Age Of Predicted Structures, Kun Hee Kim

Dissertations and Theses (Open Access)

Recognition of antigen by a T cell begins with a single physical event, the engagement of the T cell receptor (TCR) with a peptide-major histocompatibility complex (pMHC), and this interaction is encoded in the geometry with which the receptor docks onto the composite pMHC surface. Whether that docking geometry is biologically organized, and whether the structures now produced at scale by prediction preserve recognition or only reproduce that organization, are the two questions this thesis addresses. Two gaps stand in the way. The first is a gap of measurement, because docking geometry has never been made quantitatively comparable across many …

Membrane Organization Of Rheb And Rhoa: Roles In Function And Allosteric Druggability, Chase M. Hutchins

Dissertations and Theses (Open Access)

Small GTPases of the Ras superfamily are membrane-bound molecular switches that regulate nearly all major cellular processes, and their dysregulation drives cancers, neurological disorders, and metabolic diseases. While anchored to cellular membranes, the catalytic domains of small GTPases undergo orientation dynamics, adopting distinct configurations that can occlude or expose effector-binding surfaces and modulate signaling output. These dynamics have been characterized in the Ras oncoproteins, but whether they extend across the superfamily and influence allosteric druggability has remained unknown.

In this dissertation, I address these questions through Rheb and RhoA, two small GTPases with complementary differences in subfamily lineage, membrane localization, …

Context Dependent Regulation Of Dicer Function During Oocyte-To-Embryo Transition, Nick A. Newkirk

Dissertations and Theses (Open Access)

Over two decades ago, Dicer was discovered as the primary enzyme responsible for the generation of small RNAs known as the microRNAs (miRNAs) and short interfering RNAs (siRNAs). Spatiotemporal regulation of Dicer-dependent small-RNA biogenesis affects many aspects of biology, including aging, disease progression, fertility, and cancer. Interestingly, a distinct population of Dicer-dependent small RNAs, known as the endogenous siRNAs (endo-siRNAs), are uniquely abundant in the germ cells and gametes, and are critical for normal fertility. Despite their function regulating new life, the mechanisms controlling their biogenesis and subsequent germ cell functions remain poorly defined. Work to parse these mechanisms in …

Use Of The Protein Misfolding Cyclic Amplification For Food Safety And Drug Discovery, Maria R. Benavente Garcia-Huidobro

Dissertations and Theses (Open Access)

Prion diseases are fatal neurodegenerative disorders caused by the misfolding of the normal prion protein (PrP^C) into its infectious form (PrP^Sc). While the zoonotic potential of chronic wasting disease (CWD) remains uncertain, the presence of prions in food products raises public health concerns. Additionally, therapeutic strategies for prion diseases remain limited. This thesis presents a methodological exploration of the Protein Misfolding Cyclic Amplification (PMCA) technique to address these challenges in two key areas: (1) detecting CWD prions in processed meats subjected to common cooking procedures, and (2) identifying potential anti-prion compounds through a high-throughput PMCA adaptation. …

Structural Functional Investigation Of Hap40, Amanda M. Solbach

Dissertations and Theses (Open Access)

STRUCTURAL FUNCTIONAL INVESTIGATION OF HAP40

Amanda Marie Solbach

Dissertation Advisor: Sheng Zhang, Ph.D.

Huntington’s disease (HD) is a devastating neurodegenerative disorder caused by an expanded CAG trinucleotide repeat in the Huntingtin (HTT) gene, resulting in a mutant huntingtin (mHTT) protein with an elongated polyglutamine tract. While the genetic basis of HD is well established, the mechanisms underlying mHTT toxicity and its impact on cellular function remain incompletely understood. Recent discoveries implicate Huntingtin-associated protein 40 (HAP40) as a critical regulator of HTT stability and intracellular function. However, the physiological and pathological significance of this interaction has not been fully explored.

This …

Fc Gamma Receptors Facilitate Antigenic Modulation Of Lilrb4 And Function As Predictive Biomarkers In Acute Monocytic Leukemia, Joshua Morse

Dissertations and Theses (Open Access)

Acute monocytic leukemia (monocytic AML) is a subtype of AML marked by a proliferation of abnormal monoblasts. This subtype represents approximately 10% of AML cases. The prognosis of monocytic AML is poor, with a 5-year survival of ~30%. Most patients are diagnosed at an age when they are unlikely to survive first-line non-targeted cytotoxic chemotherapy as a bridge to hematopoietic stem cell transplant (HSCT). Even patients who achieve remission commonly relapse. This population of patients would greatly benefit from precision-targeted therapies but currently there are none approved for monocytic AML.

Leukocyte immunoglobulin-like receptor B4 (LILRB4) is an immune checkpoint expressed …

Expanding Inducible Epithelial Resistance Against Pneumonia: Novel Virus, Novel Receptor, Michael Longmire

Dissertations and Theses (Open Access)

Pneumonia is the leading infectious cause of death worldwide and presents a continuing risk among immunocompromised patients. Our work has been focused for many years on the phenomenon of inducible epithelial resistance, where activation of the innate immune response in the airway epithelium is necessary and sufficient to produce a pathogen-killing but self-protective environment to prevent severe disease. Inducible resistance is pathogen-agnostic and has been demonstrated against an array of respiratory infections. We achieve this using a combination of pattern recognition receptor agonists – Pam2CSK4 and ODN M362 being the current formulation – which produce synergistic levels of pathogen reduction …

Impact Of Tumor Cell Expressed Cd38 On Metastasis And Immune Evasion In Breast Cancer, Tanvi Visal

Dissertations and Theses (Open Access)

Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer subtype. The epithelial-to-mesenchymal transition (EMT) of cancer cells is a key feature of the metastatic cascade and is not a binary process but often generates malignant cells with both epithelial (E) and mesenchymal (M) traits known as hybrid EM cells. Recent studies highlight the enhanced metastatic potential of the hybrid EM cells. However, molecular insights and targetable vulnerabilities within hybrid EM remain elusive. We discovered that hybrid EM murine tumors are enriched in CD38, an immunesuppressive molecule associated with worse clinical outcomes in liquid malignancies but relatively understudied in solid …

The Extracellular Domains Of The Ampa, Kainate, And Orphan Delta Receptor Regulate Channel Gating In Distinct Ways, Cuauhtemoc Ulises Gonzalez

Dissertations and Theses (Open Access)

The ionotropic glutamate receptors are ligand-gated cationic channels essential for neuroplasticity and neurological functions such as learning, memory, behavior, cognition, and motor coordination. Mutations in these channels are linked to various disorders including autism, ataxia, and epilepsy, making them compelling pharmacological targets. Within this family, the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) and kainate receptor mediate their function through fast glutamate-gated ionotropic activity, which needs precise structural changes to perform properly. While Cryo-EM structures have provided snap shots of these proteins, questions remain regarding the dynamics across conformations and individual roles of the extracellular amino-terminal and agonist binding domain in dictating function. …

Overcoming Resistance To Cdk4/6-Targeted Therapy Using Jak2/Stat3 Inhibitor In Triple-Negative Breast Cancer, Chuling Zhuang

Dissertations and Theses (Open Access)

Breast cancer is the most common type of cancer diagnosed in women, with nearly 30% of cases becoming metastatic accounting for over 90% of breast cancer-related deaths. Among different breast cancer subtypes, triple-negative breast cancer (TNBC) has the worst prognosis and the highest propensity to metastasize. However, TNBC patients have limited treatment options due to their lack of actionable drug targets while therapeutic resistances result in high rates of recurrence and metastasis. Cyclin-dependent kinase 4 and 6 (CDK4/6) are major cell cycle regulators that control G1 to S phase transition and aberrant hyperactivation of the CDK4/6 pathway results in uncontrolled …

Role Of Mir-4732-3p In Breast Cancer Brain Metastasis And Brain Metastatic Tumor Microenvironment, Munazza Samar Khan

Dissertations and Theses (Open Access)

In this study, we aimed to identify microRNAs (miRNAs) that may play important roles in breast cancer brain metastasis (BCBM). To this end, we conducted miRNA-sequencing of extracellular vesicles isolated from the serum samples of 6 BCBM patients and 8 Stage I/II/III breast cancer patients, and identified 49 circulating miRNAs that were upregulated in BCBM patients compared to Stage I/II/III breast cancer. Upon further analysis, we identified miR-4732-3p to be upregulated in brain-tropic triple-negative breast cancer (TNBC) cell lines, compared to parental lines. MiR-4732-3p overexpression increased metastatic properties of TNBC cells, including proliferation, migration, invasion, and maintenance of a mesenchymal …

Investigating Metabolic And Mitochondrial Adaptations Triggered By Blood Flow During The Endothelial-To-Hematopoietic Transition, Paulina Horton

Dissertations and Theses (Open Access)

Hematopoietic stem cell (HSC) transplant is the standard of care for many hematologic diseases. However, many patients cannot benefit from this potentially curative treatment because they cannot find a suitable donor, contributing to a high level of unmet need. Recently, bona fide HSCs capable of robust engraftment and differentiation have been generated from iPSCs utilizing wall shear stress (WSS) to help promote HSC generation. However, the mechanisms through which WSS regulates hematopoiesis remain poorly understood. Scientists, therefore, continue to look for the mechanotransduction pathways that promote hematopoiesis, and key answers may lie in examining the role of extrinsic factors that …

Assessing The Temporal Role Of Mir-200 Loss In Murine Models Of Nsclc, Jared Fradette

Dissertations and Theses (Open Access)

Lung cancer is the leading cause of cancer related deaths in the United States, with non-small cell lung cancer (NSCLC) making up a majority of new diagnoses. Metastasis is the big killer in NSCLC and is driven by epithelial-mesenchymal transition (EMT) and immune evasion. The microRNA 200 family is a master regulator of EMT and is implicated in immune regulation. In this study we have developed a novel genetically engineered mouse model (GEMM) and derived primary cell lines from them to explore the role of microRNA-200 in early EMT and immune changes. Our model combines conditional activation of Kras^{G12D …}

Unveiling The Intercompartmental Signaling Axis: Mitochondrial To Er Stress Response (Mersr) And Its Impact On Proteostasis, Jeson Li

Dissertations and Theses (Open Access)

Maintaining protein homeostasis is essential for cellular health. During times of protein stress, cells deploy unique defense mechanisms to achieve resolution. Our previous research uncovered a cross-compartmental Mitochondrial to Cytosolic Stress Response (MCSR), a unique stress response activated by the perturbation of mitochondrial proteostasis, which ultimately results in the improvement of proteostasis in the cytosol. Here, we found that this signaling axis also influences the unfolded protein response of the endoplasmic reticulum (UPRER), suggesting the presence of a Mitochondria to ER Stress Response (MERSR). During MERSR, the IRE1 branch of UPRER is inhibited, introducing a previously unknown regulatory component of …

Placental Co-Transcriptional Activator Vestigial-Like 1 (Vgll1) Drives Tumorigenesis Via Increasing Transcription Of Proliferation And Invasion Genes, Heather Sonnemann

Dissertations and Theses (Open Access)

Vestigial-like 1 (VGLL1) is a co-transcriptional activator that binds to TEA domain containing transcription factors (TEADs). Its expression is upregulated in a variety of aggressive cancer types, including pancreatic and basal-like breast cancer, and increased transcription of VGLL1 is strongly correlated with poor prognosis and decreased overall patient survival. In normal tissues, VGLL1 is most highly expressed within placental trophoblast cells, which share the common attributes of rapid cellular proliferation and invasion with tumor cells. The impact of VGLL1 in cancer has not been fully elucidated and no VGLL1-targeted therapy currently exists. The aim of this study was to evaluate …

The Role Of The Circadian Clock In Disease And Tissue Function, Marvin Wirianto

Dissertations and Theses (Open Access)

The mammalian circadian clock responds to the 24-hour daily cycle and regulates tissue-specific gene expression and downstream physiology. The central pacemaker located in the hypothalamic suprachiasmatic nuclei (SCN) synchronizes the peripheral clocks in different tissues. This dissertation aims to uncover specific circadian regulatory mechanisms in the brain and skeletal muscle.

Alzheimer’s Disease (AD) is the most common type of dementia. It has previously been shown that there is a strong correlation of disease progression with circadian rhythm decline. We showed that circadian modulation by a small molecule Nobiletin (NOB) was able to mitigate AD pathogenesis. Furthermore, NOB significantly alleviated the …

Epigenetic Modification As A Therapeutic Target In Brafv600e-Mutated Metastatic Colorectal Cancer, Hey Min Lee

Dissertations and Theses (Open Access)

Patients with BRAF^V600E-mutated metastatic colorectal cancer (mCRC) experience a worse prognosis and demonstrate only a 5% response rate to BRAF inhibitor treatment. In this study, adaptive resistance, and a potential combination of standard therapies in BRAF^V600E CRC were unveiled. Intriguingly, a robust association of BRAF^V600E mutation and DNA hypermethylation suggests this is a unique subgroup harboring aberrant epigenetic phenotype. Firstly, DNA methyltransferase (DNMT) inhibitor treatment induced profound DNA hypomethylation in vivo, but minimal change in gene expression due to adaptive elevation of the repressive histone methylation, H3K27me3, leading to compensatory suppression of key tumor suppressor genes, …

Structural And Functional Studies Of Ascc1 In Dna And Rna Alkylation Damage Response, Naga Babu Chinnam

Dissertations and Theses (Open Access)

Alkylating agents from environmental, endogenous, and certain chemotherapeutic sources constantly challenge cellular nucleic acids. Repairing the damage caused by alkylation is necessary for maintaining genomic stability. ALKB family Human Homolog ALKBH3 plays a key in repairing alkylated damages in DNA and RNA molecules. Activating signal co-integrator complex 1 (ASCC1) acts with ASCC-ALKBH3 complex in alkylation damage responses. ASCC1 uniquely combines two evolutionarily ancient domains: nucleotide-binding K-Homology (KH) (associated with splicing, transcriptional regulation, and translational control) and two-histidine phosphodiesterase (PDE) (associated with hydrolysis of cyclic nucleotide phosphate bonds). Germline mutations link ASCC1 loss of function to spinal muscular atrophy with congenital …

A Cancer-Specific Study On The Differentially Expressed Protein-Protein Interactions Of Fumarate Hydratase, Sydney Lac

Dissertations and Theses (Open Access)

Fumarate hydratase (FH) is an enzyme used in the Krebs Cycle to convert fumarate to malate, and it is controlled by the FH gene. In this paper, we will investigate its role in Uterine Corpus Endometrial Carcinoma (UCEC) and how FH-deficient cells affect tumorigenesis. It is well-established that FH has been extensively studied in connection with renal cell carcinoma, skin and uterine leiomyomas, pheochromocytoma, and paraganglioma. However, we aim to construct an interaction network of significant genes related to the FH gene under conditions of FH deficiency in the Kreb Cycle. Creating an interactive network that illustrates the interconnectedness of …

Development Of Novel Methods To Study Host-Microbe Interactions In The Larval Zebrafish Gastrointestinal Tract, Anh K. Trinh Nguyen

Dissertations and Theses (Open Access)

The dynamic nature and inaccessible location of the intestine pose significant challenges to the study of intestinal physiology and pathology. Zebrafish larvae, possessing optical transparency and genetic tractability, offer an accessible and clinically relevant model for investigating dynamic events in the intestine via time-lapse imaging. In the first part of this work, I discuss our efforts to optimize the parameters of a foodborne infection assay using paramecia as a vehicle. This method provides an effective, high-throughput alternative to infection via immersion or oral gavage, and replicates the most common route of transmission of gastrointestinal (GI) infection in humans. The foodborne …

A Signal To Divide: Apoptotic Extracellular Vesicles As Carriers Of Mitogenic And Immunogenic Signals, Safia Essien, Safia Essien

Dissertations and Theses (Open Access)

Efficient replacement of dead cells in epithelial tissue is crucial for maintaining barrier function and tissue homeostasis. Apoptotic cells can signal to neighboring cells to stimulate proliferation and compensate for cell loss and maintain overall cell numbers in normal physiology and cancer. While dying cells can transmit instructive cues to neighboring cells, the molecular mechanisms that induce cell division are not well understood. Recent evidence suggests that apoptotic bodies (ABs) or apoptotic extracellular vesicles (AEVs) mediate cell-to-cell communication and carry diverse biologically active cellular cargo which can influence cell proliferation. This dissertation visualizes and characterizes AEVs in larval zebrafish and …

Acute Manipulation Of Erna Level For Dissecting Its Roles In Transcriptional Regulation, Lanxin Bei

Dissertations and Theses (Open Access)

Enhancers are the central genetic elements controlling cell-type and state specific transcription programs to dictate cell fates during development. Mechanistic understanding of enhancer action is important for both biology and disease research. In the human genome, more than 60k human enhancers were found to produce non-coding transcripts named enhancer RNAs (eRNAs). These created a new challenge to understand enhancer functions, which now are not only DNA elements that promote transcription but also RNA-producing transcription units themselves. Importantly, deregulation of eRNAs was associated with various diseases such as cancer, immune disorders, and neurodegeneration. However, the direct role of eRNAs in transcriptional …

Targeting Metabolic Alterations Associated With Smooth Muscle Α-Actin Pathogenic Variant Attenuates Moyamoya-Like Cerebrovascular Disease, Anita Kaw

Dissertations and Theses (Open Access)

Heterozygous pathogenic variants in ACTA2, encoding smooth muscle α-actin (α-SMA), predispose to thoracic aortic aneurysms and dissections. De novo missense variants disrupting ACTA2 arginine 179 (p.Arg179) cause a multisystemic disease termed smooth muscle dysfunction syndrome (SMDS), which is characterized by early onset thoracic aortic disease and moyamoya disease-like (MMD) cerebrovascular disease. The MMD-like cerebrovascular disease in SMDS patients is marked by bilateral steno-occlusive lesions in the distal internal carotid arteries (ICAs) and their branches. To study the molecular mechanisms that underlie the ACTA2 p.Arg179 variants, a smooth muscle-specific Cre-lox knock-in mouse model of the heterozygous Acta2 R179C variant, termed …

Elucidating The Direct Role Of M6a In The Human Transcriptome, Lana Al Hasani

Dissertations and Theses (Open Access)

The best characterized and most abundant internal RNA modification is the methylation of adenosine at position 6 to give N6-methyladenosine (m6A). m6A modification on cellular RNAs was discovered in the 1970s. The past decade has witnessed major progress that illustrated important roles of this mark in various aspects of gene control. Due to its pleiotropic roles, the direct effect of m6A regulation of gene expression has remained incompletely understood. Traditional methods of understanding protein function, like CRISPR/Cas9 and RNA interference, have many limitations and have halted the process of fully understanding the direct functions of m6A. Here, we attempt alternative …

Regulation And Function Of Zeb1 Acetylation In Lung Adenocarcinoma Progression And Metastasis, Mabel Perez-Oquendo

Dissertations and Theses (Open Access)

Lung cancer metastasis is leading the causes of cancer-related mortality in the United States and worldwide. Epithelial-to-mesenchymal transition (EMT) is a model for metastasis that results in loss of specialized epithelial cell contacts and acquisition of mesenchymal invasive capacity. Zinc finger E-box-binding homeobox 1 (ZEB1) recognizes and binds to E-boxes of epithelial gene promoters to repress its transcription. ZEB1 has inconsistent molecular weights, which have been attributed to post-translational modifications (PTMs). In the presented dissertation, I specifically addressed the gap in the molecular mechanisms by which PTMs of ZEB1 regulate its ability to induce EMT and how its activity might …

S-Acylation Is A Key Regulator Of Orai1/Stim1-Mediated Store-Operated Calcium Entry In T Cells, Savannah J. West Diaz

Dissertations and Theses (Open Access)

Orai1 and STIM1 proteins are the essential components of the Ca²⁺ release activated Ca²⁺ (CRAC) channel which is required for store-operated Ca²⁺ entry (SOCE) in T cells and subsequent signaling events leading to T cell activation, proliferation, and differentiation. Plasma membrane (PM)-localized Orai1 is the pore-forming subunit of the CRAC channel, and STIM1 is the Ca²⁺ sensor localized to the endoplasmic reticulum (ER) membrane in quiescent T cells. T cell receptor (TCR) stimulation leads to depletion of ER Ca²⁺ stores resulting in Ca²⁺ no longer being bound to STIM1. This activates STIM1 by triggering …

Ankyrin Dependent Mitochondrial Function And Bioenergetics In The Heart, Janani Subramaniam, Janani Subramaniam

Dissertations and Theses (Open Access)

ANK2 mutations in patients are associated with numerous arrhythmias, cardiomyopathies, and other heart defects. In the heart, AnkB, the protein encoded by ANK2, clusters relevant ion channels and cell adhesion molecules in several important domains; however, its role at Mitochondria Associated ER/SR Membranes (MAMs) has yet to be investigated. MAMs are crucial to mitochondrial function and metabolism and are signaling hubs implicated in various cardiac pathologies. Among several functions, these sites mediate the direct transfer of calcium from the ER/SR to the mitochondria to modulate ATP synthesis. Given that mitochondrial function and energy production are paramount to cardiovascular heath, …

Regulation Of Systemic And Cellular Metabolism In Prostate Cancer By Camkk2 And Elucidation Of Atgl’S Role In Disease Progression, Dominik Awad

Dissertations and Theses (Open Access)

The androgen receptor (AR) is the major driver of prostate cancer; hence, men with progressing disease are treated with androgen deprivation therapy (ADT). However, the majority of patients will relapse within 2-3 years due to multiple AR reactivation mechanisms. Thus, AR and the processes downstream of the receptor remain central drivers of prostate cancer. A direct target of AR is CAMKK2, a gene coding for the serine/threonine kinase Ca^2+/calmodulin-dependent protein kinase kinase 2 (CAMKK2), a protein upregulated in advanced prostate cancer. CAMKK2 modulates many of its pathological effects through the phosphorylation and activation of the 5' AMP-activated …

Grk3 Connects Angiogenesis And Neuroendocrine Differentiation In Prostate Cancer By Activating Hdac2 That Epigenetically Represses Tsp1 And Rest, Samira Naderinezhad

Dissertations and Theses (Open Access)

Prostate cancer (PCa) is the second most frequent cancer and the second leading cause of mortality in men in the United States. Neuroendocrine prostate cancer (NEPC) is the aggressive subset of castration-resistant prostate cancer (CRPC), found in ~20% lethal CRPC. The mechanisms underlying the progression of PCa to NEPC are still largely unclear, and new drug targets are desperately needed. NEPC is highly vascularized (angiogenic) and characterized by high expression of neuroendocrine markers. However, direct molecular links connecting angiogenesis and neuroendocrine differentiation are elusive.

Since epigenetic regulation has been implicated in NEPC progression, we examined expression patterns of 147 epigenetic …

The Role Of The Hypoxia-Inducible Factor 2 In Pancreatic Cancer: Mechanisms Of Tumor Immunosuppression And Intestinal Radioprotection, Carolina Garcia Garcia

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal prognosis. The only curative option for patients is surgery, but over 80% of patients are not surgical candidates. Unfortunately, PDAC is resistant to the three remaining options. PDAC is characterized by a profoundly hypoxic and immunosuppressive stroma, which contributes to its therapeutic recalcitrance. Alpha-smooth muscle actin+ (αSMA+) cancer-associated fibroblasts (CAFs) are the most abundant stromal component, as well as mediators of stromal deposition. The hypoxia-inducible factors (HIF1 and HIF2) coordinate responses to hypoxia, yet, despite their known association to poor patient outcomes, their functions within the PDAC tumor microenvironment (TME) …