Medicine and Health Sciences Commons^™

Role Of The Lpa2 Receptor In Protecting Against Apoptosis, Shuyu E

Theses and Dissertations (ETD)

Lysophosphatidic acid (LPA) is a naturally occurring lipid mediator. It exists abundantly in biological fluids such as serum, saliva, follicular fluid, seminal fluid and malignant effusions and induces a vast array of biological responses affecting cell growth, survival, differentiation, migration and morphology. We recently identified lysophosphatidic acid (LPA) as a potent antiapoptotic agent for the intestinal epithelium. Based on computational modeling octadecenyl thiophosphate (OTP) was synthesized: a novel rationally designed, metabolically stabilized LPA mimic. OTP was more efficacious than LPA in reducing g-irradiation-, camptothecin-, or TNF-a/cycloheximide-induced apoptosis and caspase 3, 8 and 9 activity in the IEC-6 cell line. The …

Abcb6 Is A Porphyrin Transporter With A Novel Trafficking Signal That Is Conserved In Other Abc Transporters, Yu Fukuda

Theses and Dissertations (ETD)

The ATP-binding cassette (ABC) transporters play an important role as a barrier to protect cells from the accumulation of toxic xenobiotics and metabolites due to their ability to translocate a wide array of compounds across lipid bilayers. However, many ABC transporters, especially the ones localized in the intracellular organelles, are involved in critical biological processes such as antigen presentation. The core unit of ABC transporters contains two functional domains: the membrane spanning domain (MSD) and the nucleotide binding domain. The full transporters contain two of these units in tandem in a single polypeptide, whereas the half transporters only contain one …

Studies To Characterize The Requirements For The Binding And Release Of Erdj3, A Mammalian Er Dnaj Homolog, From Substrates, Yi Jin

Theses and Dissertations (ETD)

Heat shock protein 70s (Hsp70s) and their DnaJ co-factors exist in all organisms and in all eukaryotic organelles. These highly conserved chaperone pairs facilitate a large number of cellular processes. ERdj3 was identified as a soluble, lumenal DnaJ family member that binds to unassembled immunoglobulin heavy chains (HC) along with the BiP chaperone complex in the endoplasmic reticulum of mammalian cells. Here we demonstrate that ERdj3 binds directly to two unfolded substrates: immunoglobulin γHC and denatured firefly luciferase. Using mutagenesis studies on ERdj3 in both in vivo and in vitro binding assays, we defined ERdj3’s critical amino acids in domain …

The Tetraspanin Cd9 Localizes To Platelet-Platelet Contacts And Regulates Thrombus Stability, Sarah Kathleen Hill

Theses and Dissertations (ETD)

CD9, a member of the tetraspanin family, is highly expressed on platelets (50,000-80,000 copies per platelet). Tetraspanins have been implicated in modulation of integrin function, and it is hypothesized that CD9 will modulate GPIIb-IIIa, the major platelet integrin.

The association between CD9 and GPIIb-IIIa was analyzed using immunoprecipitations and confocal microscopy. These two proteins were found to associate with each other, particularly at areas of platelet-platelet contact and at the periphery. Confocal analysis revealed CD9 localization was most intense at platelet-platelet contact, as well as in platelet filopodia and lamellipodia, but there is a lack of CD9 at areas of …

Interaction Of Bacteriophage Mu Middle Transcription Activator Protein Mor With Promoter Dna, Kartik Iyer

Theses and Dissertations (ETD)

Gene expression during lytic development of bacteriophage Mu is regulated by a

transcriptional cascade in three phases: early, middle and late. Transcription from the middle promoter Pm requires the 129-amino acid transcriptional activator Mor, a product of early transcription, and the Escherichia coli RNA polymerase. The Pm promoter has a recognizable -10 hexamer but lacks a -35 hexamer. Mor binds as a dimer to an imperfect dyad-symmetrical element containing two 6-bp inverted repeats and centered at -43.5 in Pm. The goals of this study were:

1. To test the prediction from the crystal structure of Mor that residues Y70 and …

Regulation Of The Human Parainfluenza Virus (Hpiv3) Fusion Protein, Amanda Ruth Chapman

Theses and Dissertations (ETD)

Paramyxoviruses include a number of important human pathogens, including measles virus, mumps virus, and the human parainfluenza viruses (hPIV) 1-4, as well as several animal pathogens, such as Sendai virus, Nipah virus and Hendra virus. The creation of effective drugs and vaccines against this family of viruses would play an important role in decreasing the prevalence of these viruses and contributing to the health of both humans and animals worldwide. The purpose of this work was to determine how the fusion (F) protein is regulated with a focus on the heptad repeat B (HRB) region of the F protein located …

The Role Of Fgf Signaling In Retinal Development, Abbie A. Hartge

Theses and Dissertations (ETD)

The development of the retina is a precise balance between intrinsic competence and extrinsic factors. This interplay is known to regulate the generation of cell types in the developing retina and similar mechanisms have been found in other regions of the CNS. In the developing retina, FGFs are a large family of secreted polypeptide growth factors. Fgf15 is the major Fgf expressed during retinal development in mice. Fgf15 is an example of an FGF that has been shown to control proliferation, cell fate specification, differentiation and migration during development. In this thesis I used analysis of specific genes throughout retinal …

Torsina And The Pathophysiology Of Dyt1 Dystonia, Yu Zhao

Theses and Dissertations (ETD)

The goal of my dissertation work was to examine the systems biology of torsinA, a DYT1 dystonia-associated protein, by using rodent model systems. TorsinA is a putative ATPase associated with a variety of cellular activities (AAA+). Deletion of glutamic acid residue 302/303 in TOR1A is causally associated with many cases of early-onset primary dystonia.

In our work, transient forebrain ischemia and sciatic nerve transection were used as central and peripheral neural perturbations, respectively, to gain insight into the in vivo role(s) of torsinA. Moreover, transgenic mouse models that overexpress either human mutant torsinA (hMT) or wild-type torsinA (hWT) were used …

The N-Terminal Domain Of The Y-Box Binding Protein Yb-1 Plays A Major Role In Cell Proliferation And Apoptosis, Payal Khandelwal

Theses and Dissertations (ETD)

Y-box binding protein, YB-1, is a member of the cold shock domain superfamily of proteins. It is involved in a plethora of cellular functions, including cell proliferation. The molecular mechanisms governing the involvement of YB-1 in cell proliferation are still unclear. Earlier studies done in chicken pre-B lymphocyte DT-40 cells in our laboratory have shown that a targeted disruption in one allele of chicken YB-1

(Chk-Yb-1b) gene at its N-terminal domain resulted in multiple abnormalities in the heterozygous mutants, including slower growth rate, abnormal cell morphology, increased cell size, increased genomic DNA content and significant changes in levels of cell …

The Unfolded Protein Response Increases Production Of Pro-Angiogenic Factors By Tumor Cell Lines, Nan Liao

Theses and Dissertations (ETD)

The rapid growth and proliferation of tumor cells will be limited at a stage when they encounter inadequate levels of oxygen and nutrient supply within the poorly vascularized tumor mass. These severe conditions negatively affect the proper folding of nascent proteins in the endoplasmic reticulum (ER) and lead to accumulation of unfolded protein within ER which is referred to as ER stress. Consequently, it will trigger the unfolded protein response (UPR) signal pathway through ER membrane stress sensor proteins including activating transcription factor 6 (ATF6), inositol-requiring 1 (IRE1) and PKR-like ER localized kinase (PERK). The UPR is largely a cytoprotective …

Design, Synthesis, And Evaluation Of Small Molecules In The Discovery Of Novel Antimicrobial Agents, Kimberly D. Grimes

Theses and Dissertations (ETD)

The increasing prevalence of antibiotic-resistant bacteria, including Mycobacterium tuberculosis, Streptococcus pneumoniae, Staphylococcus aureus, and Enterococcus faecalis, pushes us to discover new antibacterial agents to maintain adequate patient coverage. This body of work highlights the use of medicinal chemistry methodologies that encompass cross-disciplinary fields of study. Chapter 1 gives an introduction to the antibacterial drug targets, resistance, and how scientists are working to overcome obstacles encountered with drug-resistant bacteria. It also details modern medicinal chemistry applications in antimicrobial drug discovery. Chapter 2 details the use of a structure-guided library approach to drug design, in which large virtual libraries against the target …

Factors Influencing Topotecan Cns Penetration In Mouse Models, Jun Shen

Theses and Dissertations (ETD)

Camptothecin analogs such as topotecan are currently tested in clinical trials for brain tumors. However the clinical outcome is far below the expectations, which are derived from the promising preclinical studies. This discrepancy could be partially attributed to the presence of two barrier systems in the brain, the blood brain barrier (BBB) and blood cerebrospinal fluid (CSF) barrier (BCB). Further investigations have demonstrated multiple ATP-binding cassette (ABC) transporters are present at the two barriers. Camptothecin analogs are well known substrates for several of the transporters. This work defined the role of two ABC transporters, Bcrp1 and P-gp in determination of …

The Structural And Functional Study Of Git1 Paxillin Binding Domain, Ziwei Zhang

Theses and Dissertations (ETD)

The G protein coupled receptor (GPCR)-kinase (GRK) interacting protein 1 (GIT1) is a multidomain protein that plays an important role in cell adhesion, motility, cytoskeletal remodeling, and membrane trafficking. GIT1 mediates the localization of p21-activated kinase (PAK) and PAK-interactive exchange factor (PIX) to focal adhesions, and its activation is regulated by the interaction between its C terminal paxillin-binding domain (PBD) and the LD motifs of paxillin.

In this dissertation, we determined the solution structure of rat GIT1 PBD by nuclear magnetic resonance (NMR) spectroscopy. The PBD folds into a four-helix bundle, which is structurally similar to the focal adhesion targeting …