Biochemistry, Biophysics, and Structural Biology Commons^™

Role Of Ciliary Proteins Adp Ribosylation Factor Like Gtpase 13b (Arl13b) And Bardet-Biedl Syndrome-8 (Bbs8) In Photoreceptor Outer Segment Morphogenesis, Maintenance, And Viability, Tanya L. Dilan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Photoreceptor neurons are modified primary cilia with an extended ciliary compartment known as the outer segment (OS). The mechanisms behind the elaboration of photoreceptor cilia, OS morphogenesis, and maintenance remain poorly understood. In this work, we focused on dissecting the role of two ciliary proteins, the small GTPase ADP-ribosylation factor-like GTPase 13B (ARL13B) and Bardet-Biedl Syndrome-8 (BBS8) in the context of photoreceptor biology. Both BBS8 and ARL13B are linked to defects in ciliogenesis (cilia development) and Retinitis Pigmentosa (vision loss). ARL13B is implicated in regulating ciliary length, and BBS8 is part of the Bardet-Biedl Syndrome complex (BBSome); the BBSome is …

The Impact Of Aging And Mechanical Injury On Alveolar Epithelial And Macrophage Responses In Acute Lung Injury And Inflammation, Michael S. Valentine

Theses and Dissertations

Patients with severe lung pathologies, such as Acute Respiratory Distress Syndrome (ARDS), often require mechanical ventilation as a clinical intervention; however, this procedure frequently exacerbates the original pulmonary issue and produces an exaggerated inflammatory response that potentially leads to sepsis, multisystem organ failure, and mortality. This acute lung injury (ALI) condition has been termed Ventilator-Induced Lung Injury (VILI). Alveolar overdistension, cyclic atelectasis, and biotrauma are the primary injury mechanisms in VILI that lead to the loss of alveolar barrier integrity and pulmonary inflammation. Stress and strains during mechanical ventilation are believed to initiate alveolar epithelial mechanotransduction signaling mechanisms that contribute …

Delivery Of Small Molecule And Rna Using Synthetic Polymeric Micelles And Multifunctional Exosomes For The Treatment Of Type 1 Diabetes, Yang Peng

Theses & Dissertations

Type 1 diabetes is one of the most challenging chronic autoimmune diseases. The destruction and dysfunction of insulin-secreting β cells are the results of inflammatory infiltration and the synergistic effect of multiple immune cells. The aim of this dissertation is to develop novel and reliable therapeutic approaches to advance the treatment of T1D: including chemical modification of a broad-spectrum immunosuppressant, co-application of small molecule based immune intervention and siRNA based β cell preservative therapy, and administration of a PI3K-δ/γ dual inhibitor to specifically target immune cells, utilizing synthetic polymeric micelles or natural produced multi-functional exosomes derived from human bone marrow …

Brca1 & Ctdp1 Brct Domainomics In The Dna Damage Response, Kimiko L. Krieger

Theses & Dissertations

Genomic instability is one of the enabling characteristics of cancer. DNA damage response pathways are important for genomic integrity and cell cycle progression. Defects in DNA damage repair can often lead to cell cycle arrest, cell death, or tumorigenesis. The activation of the DNA damage response includes tightly regulated signaling cascades that involve kinase phosphorylation and modular domains that scaffold phosphorylated motifs to coordinate recruitment of DNA repair proteins. Modular domains are conserved tertiary structures of a protein that can fold, function, and evolve independently from an intact protein. One of the most common modular domains involved in DNA damage …

Defining The Role Of Tyrosine Phosphorylation In The Regulation Of Connexin43 In Cardiac Diseases, Li Zheng

Theses & Dissertations

Connexins are integral membrane proteins that oligomerize to form gap junction channels. Ions and small molecules diffuse intercellularly through these channels, allowing individual cellular events to synchronize into the functional response of an entire organ. Gap junction channels composed of Connexin43 (Cx43) mediate electrical coupling and impulse propagation in the normal working myocardium. In the failing heart, Cx43 remodeling (decreased expression, altered phosphorylation state, loss at intercalated discs, and increased presence at lateral membranes) contributes to rhythm disturbances and contractile dysfunction. While there is considerable information regarding key interactions of Cx43 in the regulation of gap junction channels, unfortunately, the …

Alzheimer's And Amyloid Beta: Amyloidogenicity And Tauopathy Via Dyshomeostatic Interactions Of Amyloid Beta, Jordan Tillinghast

Senior Honors Theses

This paper reviews functions of Amyloid-β (Aβ) in healthy individuals compared to the consequences of aberrant Aβ in Alzheimer’s disease (AD). As extraneuronal Aβ accumulation and plaque formation are characteristics of AD, it is reasonable to infer a pivotal role for Aβ in AD pathogenesis. Establishing progress of the disease as well as the mechanism of neurodegeneration from AD have proven difficult (Selkoe, 1994). This thesis provides evidence suggesting the pathogenesis of AD is due to dysfunctional neuronal processes involving Aβ’s synaptic malfunction, abnormal interaction with tau, and disruption of neuronal homeostasis. Significant evidence demonstrates that AD symptoms are partially …

Natural Variation In Yeast Stress Signaling Reveals Multiple Paths To Similar Phenotypes, Amanda N. Scholes

Graduate Theses and Dissertations

Natural environments are dynamic, and organisms must sense and respond to changing conditions. One common way organisms deal with stressful environments is through gene expression changes, allowing for stress acclimation and resistance. Variation in stress sensing and signaling can potentially play a large role in how individuals with different genetic backgrounds are more or less resilient to stress. However, the mechanisms underlying how gene expression variation affects organismal fitness is often obscure.

To understand connections between gene expression variation and stress defense phenotypes, we have been exploiting natural variation in Saccharomyces cerevisiae stress responses using a unique phenotype called acquired …

A Novel Switch-Like Function Of Delta-Catenin In Dendrite Development, Ryan Baumert

Dissertations and Theses (Open Access)

The formation of neuronal networks in the brain is tightly regulated, and dependent on the morphology of dendrites, the branch-like signal-receiving structures extending from neurons. Disruptions in dendrite development, or dendritogenesis, can lead to the atypical neuronal connectivity associated with multiple neurodevelopmental diseases. My research addresses molecular processes that underlie dendritogenesis via analysis of a pair of novel interactions involving the protein delta-catenin.

In neurons, delta-catenin localizes to dendrites and synapses, where it functions in their development and maintenance. Structurally, delta-catenin possesses a central Armadillo domain and a C-terminal PDZ-binding motif. This motif associates with PDZ domain-containing proteins, and is …

The Role Of Membrane Domains In Protein And Lipid Sorting During Endocytic Traffic, Blanca B. Diaz-Rohrer

Dissertations and Theses (Open Access)

The lipid and protein composition of the plasma membrane (PM) must be tightly controlled to maintain cellular functionality, despite constant, rapid endocytosis. Because de novo synthesis of proteins and lipids is energetically costly, the cell depends on active recycling to return endocytosed membrane components back to the PM. For most proteins, the mechanisms and pathways of their PM retention remain unknown. The work presented here shows that association with ordered membrane microdomains is fully sufficient for PM recycling and that abrogation of raft partitioning leads to their degradation in lysosomes. These findings support a model wherein ordered membrane domains mediate …

Toward Understanding The Mechanism Of Protein Targeting In The Chloroplast Signal Recognition Particle Pathway, Mercede Furr

Graduate Theses and Dissertations

Protein targeting is a vital cellular function. The signal recognition particle (SRP) pathway is a universally conserved targeting system present in the cytosol and used to co-translationally target many proteins to the inner membrane of prokaryotes and the endoplasmic reticulum of eukaryotes. The chloroplast has a homologous SRP system which post-translationally targets light harvesting chlorophyll binding proteins (LHCPs) to the thylakoid membrane for integration. The chloroplast SRP (cpSRP) is a heterodimer with a 54 kDa subunit equivalent to SRP54 in the canonical pathway. In addition, cpSRP contains a novel 43 kDa subunit which is a unique and irreplaceable component. cpSRP43 …

The Role Of Atypical Protein Kinase C In Colorectal Cancer Cells Carcinogenesis, S M Anisul Islam

USF Tampa Graduate Theses and Dissertations

Colorectal cancer (CRC) is the third most common malignancy and the fourth most common cause of cancer-related death worldwide. CRC is a life-threatening disease due to therapy-resistant cancerous cells. The exact mechanisms of cell growth, survival, metastasis and inter & intracellular signaling pathways involved in CRC are still a significant challenge. Moreover, the treatment of metastatic CRC considered palliative for many years aimed for an improved life, with little hope of a cure, highlighting the need for developing novel targeted therapy for CRC. Hence, investigating new molecular mechanism(s) that lead to colorectal carcinogenesis may give insight into the therapeutic target. …

The Democratization And Development Of Cell-Free Protein Synthesis, Max Z. Levine

Master's Theses

Cell-free protein synthesis (CFPS) using crude lysates has developed into a robust platform technology over the last 60 years to express numerous types of recombinant proteins. The open-nature, elimination of reliance on cell viability, and focus of all energy towards production of the protein of interest represent substantial advantages of CFPS over in vivo protein expression methods. CFPS has provided new opportunities across a series of research fields that include metabolic engineering, therapeutic and vaccine development, education, biosensors, and many more. In recent years, optimizations of CFPS have even allowed the platform to reach the industrial level of protein production. …

All Nuts And No Bolts: The Evolution Of Undergraduate Research At A Small State School, James Hawker

Florida Statewide Symposium: Best Practices in Undergraduate Research

In fall of 2017, students first started doing research with their biology instructor, and just a few terms later, two students have earned Portz Interdisciplinary Fellowships. In some ways, the program is going well with students participating in high numbers, but organizers still have questions about the “nuts and bolts” of establishing the program within the institution. Enthusiasm is high! However, key metrics are not being tracked and the workload needs to be distributed more evenly. The organizers will be talking with the audience about different ways to integrate UGR into the institution.

Regulation Of The Microtubule Cytoskeleton And Cell Wall Development In Arabidopsis Thaliana, Christy J. Fornero

Theses and Dissertations

Regulation of the cortical microtubule cytoskeleton is critical for organized plant cell division. Arabidopsis ton1 and ton2 mutants display random cell division plane placement and lack the plant-specific cortical microtubule array that encircles the nucleus prior to mitosis. In wild type plants, this preprophase band (PPB) of cortical microtubules precisely marks the future division plane. The specific roles of TON1 and TON2 in PPB formation are not yet known. It is suspected that TON1 Recruiting Motif (TRM) proteins may be involved in TON1 and TON2 recruitment to the PPB. Here we describe results for the targeted disruption of a group …

Hyaluronan At The Brain-Environment Interface, Donald M. Thevalingam

Dissertations, Theses, and Capstone Projects

Hyaluronan (HA; Hyaluronic Acid), a primary scaffolding component of the brain extracellular matrix, serves as an integral structural component to the brain extracellular space (ECS). The fossorial African naked mole-rat (Heterocephalus glaber; NM-R), a mammal which lives in a low-oxygen environment and is capable of tolerating hypoxia and hypercapnia, has been shown to synthesize and sustain a unique high-molecular-mass variant of hyaluronan macromolecule (HMM-HA). This body of work highlights HA’s role in mediating the interplay between brain ECM composition, ECS structure, and cell viability.

Here we employ the NM-R as a unique animal model to observe the role of the …

Towards A Mathematical Model Of Motility Using Dictyostelium Discoideum: Proteins And Geometric Features That Regulate Bleb-Based Motility, Zully Santiago

Dissertations, Theses, and Capstone Projects

A variety of biological functions depend on actin organization. The organization of actin is tightly regulated by a plethora of extracellular and intracellular signaling, scaffolding, and actin-binding proteins. Dysfunctions in this regulation lead to immune diseases, increased susceptibility to pathogens, neurodegenerative diseases, developmental disorders, and cancer metastasis. A variety of actin-dependent processes, including cell motility, are regulated by several proteins of interest: Paxillin, a scaffolding protein; WASP, an actin nucleating protein; SCAR/WAVE, another WASP family actin nucleating protein; Talin, a cortex-to-membrane binding protein; Myosin II, an F-actin contracting motor protein; and Protein Kinase C, a protein kinase. D. discoideum cells …

Inhibition Of Mitochondrial Permeability Transition By Deletion Of The Ant Family And Cypd, Jason Karch, Michael J. Bround, Hadi Khalil, Michelle A. Sargent, Nadina Latchman, Naohiro Terada, Pablo M. Peixoto, Jeffery D. Molkentin

Publications and Research

The mitochondrial permeability transition pore (MPTP) has resisted molecular identification. The original model of the MPTP that proposed the adenine nucleotide translocator (ANT) as the inner membrane pore-forming component was challenged when mitochondria from Ant1/2 double null mouse liver still had MPTP activity. Because mice express three Ant genes, we reinvestigated whether the ANTs comprise the MPTP. Liver mitochondria from Ant1, Ant2, and Ant4 deficient mice were highly refractory to Ca2+-induced MPTP formation, and when also given cyclosporine A (CsA), the MPTP was completely inhibited. Moreover, liver mitochondria from mice with quadruple deletion of Ant1, Ant2, Ant4, and Ppif (cyclophilin …

Natural Autoantibodies: Origin, Function And Utility For Diagnosis Of Disease, Abhirup Sarkar

Graduate School of Biomedical Sciences Theses and Dissertations

Autoantibodies (aAbs) by the simplest definitions have been described as antibodies against self-antigens and were exclusively associated with autoimmune diseases. Eventually, studies demonstrated that they are abundant in the blood of all human sera, regardless of age, gender, or the presence or absence of disease, and were thus named as ‘natural autoantibodies’. The underlying reason for their ubiquity has remained elusive, but we have hypothesized that they are responsible for clearing blood-borne cell and tissue debris generated under conditions of health and disease. To test this, we chose to use two widely different disease model systems, namely neurodegenerative diseases and …

Sensory Primary Cilium Is A Distinct Signaling Compartment, Rinzhin Tshering Sherpa

Pharmaceutical Sciences (PhD) Dissertations

The primary cilium is a solitary cellular organelle that protrudes from the apical cell membrane. Findings on cilia-dependent mechanosenstation have shown that the primary cilium acts as a transducer of fluid-shear stress into intracellular signaling. Over recent years, studies in primary cilia have intensified after determining a causal relationship between dysfunctional primary cilia and cystic diseases. Along with its mechanosensory function, the primary cilium houses a variety of receptors, ion channels and transporter proteins. Studies in cilia biology have shown that primary cilia are coordinators of signaling pathways such as Hedgehog (Hh), Wnt, and platelet-derived growth factor (PDGF) pathways during …

The Influence Of Mir-322 On Skeletal Muscle Differentiation, Miles Alexander Soyer

Legacy Theses & Dissertations (2009 - 2024)

Skeletal muscle plays a crucial role in coordinating voluntary movement and accounts for nearly 50% of total body mass. Dysregulation in skeletal muscle development is known to cause muscle degenerative diseases including the devastating Duchenne Muscular Dystrophy (DMD). The majority of the biological studies investigating muscle development were based on myogenic transcription factors and signaling molecules including: Pax7, Myf5, MyoD, WNT, TGF-β and BMP. After the discovery of non-coding RNAs including microRNAs, it was postulated that these molecules could regulate gene expression and thus affect differentiation and development. MicroRNAs are small non-coding RNAs (~17-25 nucleotides) that regulate gene expression negatively …

Protein Structure Analysis, Agnieszka Szarecka, Chris Dobson

Peer Reviewed Articles

We describe a series of engaging exercises in which students emulate the process that researchers use to efficiently develop new pharmaceutical drugs, that of rational drug design. The activities are taken from a three- to four-hour workshop regularly conducted with first-year college students and presented here to take place over three to four class periods. Although targeted at college students, these activities may be appropriate at the high school level as well, particularly in an AP Biology course. The exercises introduce students to the topics of bioinformatics and computer modeling, in the context of rational drug design, using free online …

Ipsc Based Gene Correction And Disease Model Of A New Class Of Lgmd Due To Poglut1 Mutation, Jose Ortiz-Vitali

Dissertations and Theses (Open Access)

Recently, a novel class of muscular dystrophy has been discovered in a family due to autosomal recessive missense mutation in POGLUT1. Mutation of this enzyme leads to decreased O-glucosyltransferase activity and impaired Notch signaling, the pathways important for skeletal muscle stem cell (satellite cells) quiescence and activation. We hypothesize that reduced POGLUT1 activity and impaired Notch signaling is causative of this limb girdle muscular dystrophy through dysfunction of muscle stem cells and myogenic progenitors.

To test this, we have used iPSCs for disease modeling and rescue experiments. Using a CRISPR based gene targeting method, we aimed to correct the point …

The Gsk-3Β-Fbxl21 Axis Regulates Tcap Via Ubiquitin-Mediated Proteasomal Pathway In The Cytoplasm, Jiah Yang

Dissertations and Theses (Open Access)

Protein turnover is one of the most essential mechanisms controlling circadian rhythms. F-Box and Leucine Rich Repeat Protein21 (FBXL21) is a circadian E3 ligase which shows oscillatory mRNA transcripts and protein levels. It was previously found to perform subcellular compartment-specific E3 ligase activities targeting the core clock proteins CRYPTOCHROME(CRY)1/2. Here we identified a new sarcomeric target substrate, Telethonin(TCAP), which also shows circadian oscillation in its mRNA transcript and protein expression and, importantly, interaction with FBXL21 in an anti-phasic manner. Via computational and pharmacological tests, we identified Glycogen Synthase Kinase-3β(GSK-3β) as a regulator of FBXL21. Biochemical and molecular characterizations demonstrated that …

The Distinct Expressions Of Integrins Αdβ2 And Αmβ2 Differently Regulate Macrophage Migration In 3d Matrix In Vitro And In Tissue During Inflammation, Kui Cui

Electronic Theses and Dissertations

Chronic inflammation is an essential mechanism during the development of cardiovascular and metabolic diseases. The outcome of diseases depends on the balance between the migration and accumulation of macrophages in damaged tissues. Macrophage motility is highly regulated by adhesive receptors, integrins. Namely, intermediate expression of integrin supports macrophage migration, while a high integrin density inhibits it. Our studies are focused on evaluation of the contribution of related integrins α_Dβ₂ and α_Mβ₂ to macrophage migration and development of chronic inflammation.

We found that integrin α_Dβ₂ is upregulated on M1-macrophages in vitro and …

Deubiquitinating Enzymes Promote Cancer Progression And Metastasis Via Regulating Protein Stability, Zhenna Xiao

Dissertations and Theses (Open Access)

Deubiquitinating enzymes (DUBs, also called deubiquitinases) are enzymes that remove monoubiquitin or polyubiquitin chains from target proteins. DUBs have critical roles in cell homeostasis and signal transduction, as they regulate protein degradation, subcellular localization, and protein-protein interaction. Deregulation of DUBs contributes substantially to tumor formation and progression, and therefore targeting DUBs may be a promising cancer therapy strategy. My dissertation focuses on identifying the DUBs of EZH2 and SNAI1, two proteins critical for cancer progression and metastasis, and establishing these DUBs as promising anti-cancer targets.

EZH2, the catalytic component of the PRC2 complex, silences gene transcription by histone methylation. High …

Targeting Pten For Therapy In Cancer And Ptenopathies, Emily Palumbo

USF Tampa Graduate Theses and Dissertations

PTEN, a dual protein and lipid phosphatase, regulates a myriad of cellular functions including PI3K pathway signaling, cell migration, proliferation, invasion and apoptosis. PTEN mutations often lead to multiple malignancies, including prostate, breast, endometrial, skin and brain cancers, associated with hyperactive PI3K signaling. PTEN mutations have also been associated with a variety of other diseases, classified as PTEN Hamartoma Tumor Syndromes (PHTS). In addition, compromised function or reduced expression of PTEN due to non-genomic mechanisms are associated with many types of hyperproliferative diseases, such as restenosis and neoplastic diseases, including melanoma, lung, breast, prostate and colon cancers. Although PI3K pathway …

Characterization Of Human Dutpase, Shawna Marie Rotoli

Graduate School of Biomedical Sciences Theses and Dissertations

Deoxyuridine nucleotidyl transferase (dUTPase) is an enzyme found in all organisms that have thymine as a component of DNA. It catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate thus precluding the buildup of dUTP pools as well as providing the substrate, dUMP, for the de novo synthesis of thymidylate. In Homo sapiens, there are four isoforms: mitochondrial (mDut), nuclear (nDut), variant 3 and variant 4. This work is largely focused on nDut. Using structural and MS analyses of recombinant dUTPase constructs, an intermolecular disulfide bridge between cysteine-3 of each nDut monomer was discovered. It was found that these two …

The Expression Of Connexin-43 By Cd11c+ Dendritic Cells Is Required To Maintain Cd4+ Foxp3+ Regulatory T Cell Population In Peripheral Lymphoid Organs, Caroline Titus Miller

Biological Sciences Theses & Dissertations

Foxp3⁺ regulatory T cells (T_R) are an immunosuppressive subset of CD4⁺ T cells that maintain homeostasis of the immune system. They are sustained by the interaction between the Major Histocompatibility Complex (MHC) molecules present on antigen presenting dendritic cells and the T Cell Receptor (TCR) expressed on T_R cells that is specific for the MHC loaded with an antigenic peptide. Here, we show that in addition to MHC/TCR interaction, Connexin-43 (Cx43) expression by dendritic cells is required to maintain the TR cell population. CD11c⁺ dendritic cells represent a major subset of antigen presenting cells. …

Endogenous Force Transmission Between Epithelial Cells And A Role For Α-Catenin, Sandeep Dumbali

Mechanical & Aerospace Engineering Theses & Dissertations

In epithelial tissues, epithelial cells adhere to each other as well as to the underlying extra-cellular matrix (ECM). E-cadherin-based intercellular junctions play an important role in tissue integrity. These junctions experience cell-generated mechanical forces via apparent adaptor proteins such as beta (β) catenin, alpha (α) catenin and vinculin. Abnormalities in these junctions may result in skin related diseases and cancers. Here, I devised methods to determine the endogenous intercellular force within cell pairs as well as in large epithelial islands. I further ascertained the factors that affect the level of inter-cellular tension.

Experiments with pairs of epithelial cells exogenously expressing …

Knocking Out A Negative Regulator Of Hedgehog Signaling Blocks Differentiation Of Cells Into Neurons, Danielle Margaret Spice, Gregory M. Kelly Ph.D.

Western Research Forum

Hedgehog (Hh) signaling, one of many different protein signaling pathways found in mammals, is vital in many stage of neural development. A major negative regulator of Hh signaling is a protein known as Suppressor of Fused (SUFU), which acts to sequester the full length Gli transcription factors, proteins that can turn genes on and off, in the cytoplasm or facilitates its conversion to a repressive form. The P19 embryonal carcinoma cell line is a model of hind-brain neuronal differentiation and the involvement of Hh signaling, in particular the role of SUFU in this process has yet to be explored. We …