Molecular Biology Commons^™

A Requirement For Y841 In Jak3 Enzymatic Activity And Hematopoietic Cancers, George Steven Martinez

Open Access Theses & Dissertations

A medical need exists for successfully treating people afflicted with leukemia, especially those who develop drug resistant forms. Relapse leukemia cases are particularly high within Hispanic populations where this disease is among the most frequently occurring cancer. Fourteen somatic mutations have been reported in Janus tyrosine kinase 3 (Jak3), including M511I and A573V, from patients with various forms of leukemia. To monitor drug sensitivity, a model system was developed. Indeed, many of these mutations have been shown to possess transforming ability in cell lines such as the IL-3 dependent pro-B cell line Ba/F3. As such, Ba/F3 cells were transformed to …

Using A Novel Multiplexing Method To Track Cell Populations And Cytodifferentiation During Development Of The Submandibular Salivary Gland, Charles Thomas Manhardt

Legacy Theses & Dissertations (2009 - 2024)

The development of submandibular salivary glands is complex and requires coordination of specific signaling events. Submandibular salivary glands originate as an epithelial invagination into the adjacent mesenchyme that leads to a single stalk and end bud; this end bud will go through a clefting process. Numerous rounds of clefting will lead to a fully developed salivary gland by this process, which is known as branching morphogenesis. As the gland undergoes morphogenesis, specific cues leading to differentiation of multiple cell types and even epithelial sub classes are required. By the later stages of development the glands are fully innervated, have an …

Altered Connexin 43 Expression Underlies Age-Dependent Decrease Of Regulatory T Cell Suppressor Function In Nonobese Diabetic Mice, Michel Kuczma, Cong-Yi Wang, Leszek Ignatowicz, Robert Gourdi, Piotr Kraj

Biological Sciences Faculty Publications

Type 1 diabetes is one of the most extensively studied autoimmune diseases, but the cellular and molecular mechanisms leading to T cell–mediated destruction of insulin-producing β cells are still not well understood. In this study, we show that regulatory T cells (T_regs) in NOD mice undergo age-dependent loss of suppressor functions exacerbated by the decreased ability of activated effector T cells to upregulate Foxp3 and generate T_regs in the peripheral organs. This age-dependent loss is associated with reduced intercellular communication mediated by gap junctions, which is caused by impaired upregulation and decreased expression of connexin 43. Regulatory …

Il-2rβ T450 Phosphorylation Is A Positive Regulator For Receptor Complex Stability And Activation Of Signaling Molecules, Blanca Estela Ruiz-Medina

Open Access Theses & Dissertations

Homeostasis of the immune system is required for proper defense against pathogenic insult. Cells of the innate and adaptive compartments provide a strictly regulated response to clear infections while allowing for self-tolerance. Dysregulation of the components of the immune system can lead to immunodeficiency, autoimmunity, and cancer. Key players of the immune response are T, B, and NK cells, which become strongly activated by IL2 through its receptor. The β subunit of the receptor becomes tyrosine, serine, and threonine phosphorylated upon induction with IL2. Phosphorylation of tyrosine residues has been extensively studied, however, the putative regulatory role of serine and …

Effect Of Hinge Region Phosphorylation On The Localization Of Thp1 In Tetrahymena Thermophila, Emily Bulley, Emily Wiley

Scripps Senior Theses

Within the cell nucleus, there are regions of highly condensed, transcriptionally silent chromatin called heterochromatin. Heterochromatin plays an important role in both chromosomal stability and gene regulation within the cell. Heterochromatin assembly is mediated by Heterochromatin Protein 1 (HP1) binding to epigenetically marked histone tails, most notably methylated H3K9. HP1 is post-translationally phosphorylated at serine and threonine residues, and this phosphorylation has been shown to increase HP1’s binding affinity for methylated H3K9 and heterochromatin formation. To study the effect of phosphorylation on heterochromatin assembly and HP1 localization within the nucleus, the unicellular protozoan Tetrahymena thermophila was used. Tetrahymena is an …

Regulation Of Set1-Mediated Methylation Of Dam1, John A. Latham

Dissertations and Theses (Open Access)

Eukaryotic genomes exist within a dynamic structure named chromatin in which DNA is wrapped around an octamer of histones forming the nucleosome. Histones are modified by a range of posttranslational modifications including methylation, phosphorylation, and ubiquitination, which are integral to a range of DNA-templated processes including transcriptional regulation. A hallmark for transcriptional activity is methylation of histone H3 on lysine (K) 4 within active gene promoters. In S. cerevisiae, H3K4 methylation is mediated by Set1 within the COMPASS complex. Methylation requires prior ubiquitination of histone H2BK123 by the E2-E3 ligases Rad6 and Bre1, as well as the Paf1 transcriptional …

Phosphorylation Of The Glycine Transporter 1, Javier Vargas Medrano

Open Access Theses & Dissertations

The extracellular levels of the neurotransmitter glycine in the brain are tightly regulated by the high-affinity glycine transporter 1 (GlyT1) and the clearance of glycine depends on its rate of transport and the levels of cell surface GlyT1. Over the past years, it has been shown that PKC activation diminishes the activity and promoted phosphorylation of several neurotransmitter transporters including the dopamine, serotonin and norepinephrine transporters however, its role is unknown for the glycine transporter. To get insights into the role of PKC activation on GlyT1 regulation, we used three N-terminus GlyT1 isoforms stably expressed in porcine aortic endothelial (PAE) …

Analysis Of The Phosphorylated Forms Of Protein Kinase R, Christine Quartararo

Honors Scholar Theses

Protein Kinase R (PKR) is induced by interferon and activated by dsRNA. Subsequent autophosphorylation and phosphorylation of eIF2alpha inhibits viral replication. In the latent state PKR exists as an unphosphorylated monomer. Work in the Cole laboratory has shown two additional states, a phosphorylated monomeric state (pPKRm) and a phosphorylated dimeric state (pPKRd). RNA serves as a scaffold bringing two PKRs together allowing dimerization and autophosphorylation to occur. The contribution of each state to the function of PKR remains unclear. Western blots were performed to examine the phosphorylation states of the essential residues,

T446 and T451. Activity assays have shown activation …

Distinct Phospho-Forms Of Cortactin Differentially Regulate Actin Polymerization And Focal Adhesions, Anne E. Kruchten, Eugene W. Krueger, Yu Wang, Mark A. Mcniven

Faculty Publications

Cortactin is an actin-binding protein that is overexpressed in many cancers and is a substrate for both tyrosine and serine/threonine kinases. Tyrosine phosphorylation of cortactin has been observed to increase cell motility and invasion in vivo, although it has been reported to have both positive and negative effects on actin polymerization in vitro. In contrast, serine phosphorylation of cortactin has been shown to stimulate actin assembly in vitro. Currently, the effects of cortactin serine phosphorylation on cell migration are unclear, and furthermore, how the distinct phospho-forms of cortactin may differentially contribute to cell migration has not been directly compared. Therefore, …

Agswe1p Regulates Mitosis In Response To Morphogenesis And Nutrients In Multinucleated Ashbya Gossypii Cells, Hanspeter Helfer, Amy S. Gladfelter

Dartmouth Scholarship

Nuclei in the filamentous, multinucleated fungus Ashbya gossypii divide asynchronously. We have investigated what internal and external signals spatially direct mitosis within these hyphal cells. Mitoses are most common near cortical septin rings found at growing tips and branchpoints. In septin mutants, mitoses are no longer concentrated at branchpoints, suggesting that the septin rings function to locally promote mitosis near new branches. Similarly, cells lacking AgSwe1p kinase (a Wee1 homologue), AgHsl1p (a Nim1-related kinase), and AgMih1p phosphatase (the Cdc25 homologue that likely counteracts AgSwe1p activity) also have mitoses distributed randomly in the hyphae as opposed to at branchpoints. Surprisingly, however, …

Camp-Dependent Protein Kinase Activation Lowers Hepatocyte Camp, Jackie D. Corbin, Stephen J. Beebe, Peter F. Blackmore

Bioelectrics Publications

Rat hepatocyte protein kinase was activated by incubating the cells with various cAMP analogs. Boiled extracts were then prepared and Sephadex G-25 chromatography was carried out. The G-25 procedure separated the analogs from cAMP since the resin had the unexpected property of binding cyclic nucleotides with differing affinities. Separation was necessary because the analogs would otherwise interfere with the sensitive protein kinase activation method developed for assay of cAMP. The cAMP analogs, but not 5'-AMP, lowered basal cAMP by 50-70%. The effect was rapid, analog concentration-dependent, and occurred parallel with phosphorylase activation, suggesting that the cAMP analogs act through cAMP-dependent …