Other Biochemistry, Biophysics, and Structural Biology Commons^™

Interaction Of The Gram-Positive Human Pathogen Staphylococcus Aureus With Host Lipids, Sharanya Paul

Theses and Dissertations

Staphylococcus aureus is a prominent pathogen that is known to incorporate straight-chain unsaturated fatty acids (SCUFAs) into its lipids in addition to the normally biosynthesized branched-chain fatty acids (BCFAs) and straight-chain fatty acids (SCFAs). Furthermore, it has recently been shown that the incorporation of oleic acid into S. aureus lipids significantly enhanced the growth of the organism at low temperatures due to the greater fluidity imparted to the membrane. Together with others in the Wilkinson and Dahl laboratory, I have shown that low-temperature growth is enhanced by various SCUFAs, including the human antimicrobial fatty acids sapienic acid, linoleic acid, and …

Identification Of A Novel Target For Declustering Supernumerary Centrosomes In Triple Negative Breast Cancer, Priyanga J

Theses and Dissertations

Triple-negative breast cancer (TNBC) confers considerable interventional challenge owing to its massive heterogeneity, aggression and metastatic prowess. These facets are attributed to chromosomal instability (CIN), a feature consequent to TNBC cell’s ability to harbor more than two centrosomes (supernumerary centrosomes; SNCs).

In principle, if a normal cell possesses SNCs, uneven pull forces are generated consequent to multipolar spindle, which activates cellular surveillance. This ensures error-free mitosis by either repairing the error or, in an irreparable condition, driving cells to death. This averts the possibility of aneuploidy (fundamental to tumorigenesis).

Unfortunately, TNBC cells, despite harboring SNCs, have devised a survival strategy …

Single-Molecule Pulldown (Simpull) For Detection Of Gpcr Complexes In Mammalian Cells, Julie M. Kraft

Theses and Dissertations

G protein-coupled receptors (GPCRs) constitute the most numerous and diverse superfamily of cell membrane receptors. While GPCRs can perform signal transduction as monomers, evidence suggests they also function as homo- and hetero- dimers and oligomers. These diverse quaternary structures can affect GPCRs’ downstream cellular signaling, pharmacological properties, and regulation of internalization.

The single-molecule pulldown (SiMPull) assay combines a co-immunoprecipitation assay with single-molecule total internal reflection fluorescence (TIRF) microscopy and can be used to probe the stoichiometry of GPCR oligomers in mammalian cells.

This project replicates the SiMPull assay by confirming the quaternary structure of mGluR2 homodimers. Plasmid constructs SNAP-mGluR2-HA and …

Characterizing 3-O-Sulfation-Induced Novel Compact Topologies In Heparan Sulfate And Their Interactions With Proteins, Samuel Holmes

Theses and Dissertations

Heparan sulfate (HS) is highly-charged, linear polysaccharide that interacts with numerous proteins in humans as consituents of proteoglycans. The action of sulfotransferase enzymes during the biosynthesis of HS can generate a combinatorially massive library of differentially sulfated sequences. Furthermore, the number and position of these sulfate groups are key to their biological activity, modulating their selectivities for certain proteins at the cell surface or ECM. The installation of a sulfate on the C3 hydroxyl of a glucosamine residue in HS represents the rarest of the sulfations, despite the HS 3-O-sulfotransferase (3OST) family being the most diverse of the other sulfotransferases. …

The Role Of Irf-1 In Spontaneous Mouse Glioma, Aakash B. Vaidya

Theses and Dissertations

Glioblastoma Multiforme has been shown to be one of the deadliest primary brain cancers. One of the reasons why GBM is so deadly, is a unique immunosuppressive tumor microenvironment that promotes GBM growth and progression. Both astrocyte and microglia have been implicated in immunosuppression. In this study, we explored the role of Interferon Regulatory Factor 1 (IRF-1) in astrocytes and glioma cells on the growth of spontaneous glioma tumors. IRF-1 is regulated by the JAK/STAT pathway and induces expression of Programmed death ligand 1 (PD-L1). PD-L1 downregulates immune responses to glioma. We found that IRF-1 had no effect on spontaneous …

Design Of Fibril Forming Collagen Mimetic Peptides: Heterotrimers And Nucleation Domains, Sally Tan

Theses and Dissertations

This paper attempts to design collagen mimetic peptides where the triple-helical region mimics that of human Type I Collagen. With consideration for chain selection and chain register, we utilize the NC2 domain of heterotrimeric Type IX Collagen as a nucleation domain for triple-helix folding.

Structural Features Contributing To Methylenedioxypyrovalerone (Mdpv) Analog Inhibition Of The Human Dopamine Transporter, Zachary R. Spires

Theses and Dissertations

Monoamine transporters (MATs) are transmembrane neurotransmitter sodium symporters consisting of the dopamine, norepinephrine, and serotonin transporters: DAT, NET, and SERT, respectively. Following an action potential and neurotransmitter vesicular release, MAT-mediated reuptake of these neurotransmitters in the presynaptic membrane contributes to the termination of monoaminergic neurotransmission. MATs are the targets of many drugs providing therapeutic benefits or taken recreationally. One of these drugs is methylenedioxypyrovalerone (MDPV), an abused synthetic cathinone that is a high potency uptake inhibitor of the human DAT (hDAT). In contrast, MDPV is a low potency uptake inhibitor of the Drosophila melanogaster dopamine transporter (dDAT). The reasons for …

Preconditioning Of The Tumor Microenvironment By Means Of Low Dose Chemotherapies For An Effective Immunotherapy Of Breast Cancer, Hussein F. Aqbi

Theses and Dissertations

Breast cancer mortality is mainly due to distant recurrence of the disease arising from dormant tumor cells established by cancer therapies. Patients who initially respond to cancer therapies often succumb to distant recurrence of the disease. It is not clear why people with the same type of breast cancer respond to treatments differently; some escape from dormancy and relapse earlier than others. In addition, some tumor clones respond to immunotherapy while others do not. We investigated how autophagy plays a role in accelerating or delaying recurrence of neu overexpressing mouse mammary carcinoma (MMC) following adriamycin (ADR) treatment, and in affecting …

Impact Of Phosphoinositides On Regulation Of K-Atp By Atp And Hydrogen Sulfide, Tyler Hendon

Theses and Dissertations

Hydrogen sulfide (H2S) reduces ischemia reperfusion (IR) injury by stimulating adenosine triphosphate (ATP) sensitive potassium channels (KATP) [1-5]. Demonstrating H2S stimulation is unique to KATP, as other inwardly rectifying potassium (Kir) channels demonstrate inhibition or are unaffected [6]. We recently showed that H2S inhibits Kir2 and Kir3 by decreasing channel sensitivity to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2) [6]. Here, we test the hypothesis that H2S regulation of Kir6.2, a pore-forming subunit of the KATP channel, is also dependent on PIP2. Using whole-cell patch-clamp we show that H2S increases the activity of Kir6.2 channels expressed in HEK-293 cells. To study the …

Rep-Dna Complexes And Their Role In Aav Dna Transactions, Vishaka Santosh

Theses and Dissertations

Adeno-associated Virus (AAV) Rep proteins are multifunctional proteins that carry out various DNA transactions required for the life cycle of AAV. The Rep proteins have been found to be important for genome replication, gene regulation, site-specific integration and play an essential role in genome packaging. There are two main groups of Rep proteins: large and small Reps; both groups are SF3 helicase family members. During DNA packaging, studies have shown that the small Rep proteins are critical to produce fully packed particles. Using stopped-flow kinetic analysis, we show a significant difference in helicase activity between the small and large Rep …