Thesis (Ph.D.)--Cleveland State University, 2008. / Abstract. Title from PDF t.p. (viewed on Oct. 8, 2008). Includes bibliographical references. Available online via the OhioLINK ETD Center. Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 76-108).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xviii, 178 p.; also includes graphics. Includes bibliographical references (p. 163-178). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xvi, 155 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 103-152).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 102 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 86-100).

Thesis (Ph. D. in Pharmacology)--Vanderbilt University, May 2006. / Title from title screen. Includes bibliographical references.

Plants possess integrated signalling networks that mediate the responses to various environmental conditions. Mitogen-activated protein kinases (MAPKs) constitute a highly conserved family of enzymes in eukaryotes, and in plants MAPK-based signal transduction modules regulate a large number of physiological processes, including responses to environmental stresses and phytohormones. Regulated dephosphorylation of active MAPKs is a key component of the control of MAPK signalling cascades, and in mammals, members of the MAPK phosphatase (MKP) sub-class of dual-specificity tyrosine phosphatases have been recognized as key players for inactivating MAPKs. Five MKP homologues are found in Arabidopsis thaliana, but only limited information is available concerning their properties and biological roles. Based on initial data derived from my reverse genetics and protein interaction studies of these five potential MKPs, as well as gene function information in the literature, I chose to focus on two putative Arabidopsis MKPs, AtMKP2 and Indole-3-Butyric Acid-response 5 (IBR5). By using a combination of genetic and biochemical studies, I established that the previously uncharacterized MKP designated AtMKP2, participates in the regulation of cellular homeostasis in ozone-challenged tissue, and can influence the activation state of two MAPKs, MPK3 and MPK6. AtMKP2-suppressed plants displayed significantly prolonged MPK3 and MPK6 activation during ozone treatment, and recombinant AtMKP2 was able to dephosphorylate both phospho-MPK3 and phospho-MPK6 in vitro, providing direct evidence that AtMKP2 may target these oxidant-activated MAPKs. A mutation in IBR5, one of the five potential AtMKPs, was previously reported to confer reduced sensitivity to auxin and ABA in Arabidopsis. My protein interaction studies demonstrated that IBR5 and MPK12 are physically coupled and that the C-terminus of MPK12 is essential for its interaction with IBR5. In vitro dephosphorylation assays indicated that recombinant phosphoMPK12 is efficiently dephosphorylated by IBR5. In transgenic plants with reduced expression of the MPK12 gene, root growth is hypersensitive to exogenous auxins, consistent with the lower auxin sensitivity reported for ibr5 mutants. Taken together, my data demonstrate for the first time that both AtMKP2 and IBR5 are bona fide Arabidopsis MAPK phosphatases and that they serve as important regulators of oxidative stress and auxin signalling, respectively, in Arabidopsis. / Science, Faculty of / Botany, Department of / Graduate

No description available.

PURPOSE: Uveal melanoma (UM) is the most common intraocular malignancy in adults with an incidence of six per one million individuals each year. Globe conserving treatments are currently the standard of care, but unfortunately, despite successful local control, a substantial mortality risk exists due to eventual emergence of distant metastasis, which is invariably lethal. There is therefore an unmet need for novel, effective, targeted therapies for metastatic UM. Somatic mutations in the G-protein α subunits, Gαq and Gα, are present in a mutually exclusive pattern in approximately 80% of UMs, and they abolish the GTPase activity, resulting in a constitutively active protein. We have previously demonstrated that GNAQ-mutant (GNAQ^mt) UMs are addicted to the oncogenic effect of the mutant GNAQ protein and dissected the GNAQ pathway in an attempt to identify druggable targets. Our findings that the mutant GNAQ protein activates the PKC/PKD axis, which activates beta-catenin (β-Catenin), prompted us to investigate the role of PKC and β-Catenin in GNAQ^mt UM. EXPERIMENTAL DESIGN: The GNAQ^mt UM cell lines Mel202 and OMM1.3 were treated with either the PKC inhibitor bisindolylmaleimide I (BIM) alone, the Wnt/β-Catenin inhibitors FH535 or cardamonin alone, the Wnt/β-Catenin activator Wnt-3a alone, or siRNAs for β-Catenin in combination with BIM, and their viability was assessed with the MTT assay. Levels of β-Catenin, phosphorylated AKT, ERK1/2, caspase 3 and LC3BII were assessed with western blotting. β-Catenin mRNA levels were assessed with microarray analysis and RT-PCR. RESULTS: GNAQ^mt UM cells are very sensitive to PKC inhibition and respond with a decrease in cell viability that involves autophagy and cleavage and translocation of LC3BII in autophagosomes, but not caspase activation. PKC inhibition results in the upregulation of β-Catenin protein, but not mRNA levels, through a post-translational mechanism that involved the phosphorylation and activation of AKT, but not ERK1/2. β-Catenin inhibition by either small molecule inhibitors or siRNA resulted in a dose-dependent increase of cell proliferation, whereas β-Catenin activation by Wnt-3a had the opposite effects, resulting in a decrease in cell viability. CONCLUTIONS: Our study demonstrates that PKC is a mediator of the oncogenic effect of mutant Gα protein in UM through the Wnt-3/β-Catenin signaling pathway. These results open exciting opportunities for the development of personalized targeted therapies for UM in a genotype-dependent fashion.

yes / Inflammation of adipose tissue in obesity is associated with increased IL-1β, IL-6 and TNF-α secretion and proposed to contribute to insulin resistance. AMP-activated protein kinase (AMPK) regulates nutrient metabolism and is reported to have anti-inflammatory actions in adipose tissue, yet the mechanisms underlying this remain poorly characterised. The effect of AMPK activation on cytokine-stimulated proinflammatory signalling was therefore assessed in cultured adipocytes. AMPK activation inhibited IL-1β-stimulated CXCL10 secretion, associated with reduced interleukin-1 receptor associated kinase-4 (IRAK4) phosphorylation and downregulated MKK4/JNK and IKK/IκB/NFκB signalling. AMPK activation inhibited TNF-α-stimulated IKK/IκB/NFκB signalling but had no effect on JNK phosphorylation. The JAK/STAT3 pathway was also suppressed by AMPK after IL-6 stimulation and during adipogenesis. Adipose tissue from AMPKα1−/− mice exhibited increased JNK and STAT3 phosphorylation, supporting suppression of these distinct proinflammatory pathways by AMPK in vivo. The inhibition of multiple pro-inflammatory signalling pathways by AMPK may underlie the reported beneficial effects of AMPK activation in adipose tissue. / British Heart Foundation