The epithelial sodium channel (ENaC) is a key regulator of salt homeostasis. The classic ENaC consists of three subunits: α, β and γ, which are highly expressed in the kidney and colon where they mediate electrogenic Na⁺ influx into cells under the tight hormonal regulation of aldosterone. A fourth ENaC subunit named [delta]ENaC also generates Na⁺ influx with the β- and γENaC subunits in Xenopus oocytes. However [delta]ENaC differs to the other subunits in its channel properties and tissue distribution, suggesting that [delta]ENaC may possess a physiological role other than salt regulation. A copper-toxicosis related protein called COMMD1/Murr1 was previously identified to directly interact with [delta]ENaC and downregulate [delta]ENaC activity. COMMD1 is linked with multiple ubiquitination pathways, therefore we hypothesised that COMMD1 directly interacts with [delta]ENaC through novel protein-protein interaction motifs and promotes internalisation of [delta]ENaC from the cell surface through enhanced ubiquitination. With the use of GST pulldown assays and coimmunoprecipitation, it was found that the binding of COMMD1 to [delta]ENaC is mediated by the COMM domain of COMMD1, primarily through amino acids 120-150 of COMMD1. Immunocytochemical studies showed that the intracellular interaction between [delta]ENaC and COMMD1 predominantly occurred in the early and recycling endosomes, suggesting that COMMD1 may promote the retrieval of [delta]ENaC from the cell surface to the intracellular pool. COMMD1 mediated a decrease in the [delta]ENaC cell surface population, as shown by a biotinylation surface labelling assay. This may be driven by an ubiquitin-regulated endocytosis, as COMMD1 increased ubiquitination, but not proteasomal/lysosomal degradation, of [delta]ENaC. COMMD1 may promote [delta]ENaC ubiquitination through the action of the ubiquitin ligase Nedd4-2 as coexpression with Nedd4-2 enhanced the COMMD1-mediated decrease in surface [delta]ENaC expression. This is abolished by the addition of the Nedd4-2 downregulator kinase sgk1, suggesting that COMMD1 may downregulate [delta]ENaC through the Nedd4-2/sgk1 pathway. Surface levels of [delta]ENaC may also be affected by XIAP, a RING domain ubiquitin ligase which is able to decrease the levels of COMMD1. Coimmunoprecipitation of endogenous [delta]ENaC and COMMD1 proteins, and the enhanced colocalisation of endogenous [delta]ENaC in the recycling endosomes with transfected COMMD1, indicate that interaction between transfected [delta]ENaC and COMMD1 reflect the intracellular interactions of the endogenous proteins. Taken together, these findings suggest that COMMD1 downregulates [delta]ENaC activity by promoting the internalisation of surface [delta]ENaC into early and recycling endosomes and this may be mediated by enhanced [delta]ENaC ubiquitination via the ubiquitin ligase Nedd4-2.

Thesis (Ph. D.)--Oregon Graduate Center, 1979.

Thesis (Ph. D.)--Columbia University, 1944. / Lithoprinted, Edwards brothers, inc. Vita. Bibliography: p. 30-32.

No description available.

Thesis (Ph. D.)--Oregon Graduate Center, 1980.

Ph.D. / Inorganic Chemistry / Copper (I) forms π complexes with olefin-containing metal complexes in aqueous solution. Reduction of a series of pyridinepentaammineruthenium (III) ions, where L is a pyridine or 4-substituted pyridines, was studied. For the (NH[subscript 3]) [subscript 5] Ru (III)-4-viny1pyridine ion it is possible to measure separately preequilibrium binuclear ion formation and electron transfer. The electron transfer pathway is determined to be intramolecular from comparison with rate behavior of (NH[subscript 3]) [subscript 5] (III)-4-ethylpyridine, Cu (I) and (NH[subscript 3]) [subscript 5] (III)-pyridine, Cu (I) redox pairs. Rate parameters are also determined for the reverse reaction. Cu (II) catalyzed autoxidation of the (NH[subscript 3]) [subscript 5] (II) - 4-vinylpyridine ion. The redox equilibrium constant determined from the kinetic data agrees reasonably with that calculated from the redox potentials of the reactants. Qualitative models have been advanced from which it is suggested that the entropy of activation gives a measure of the probability for electron transfer in the activated complex, values near zero indicating that electron-tunneling is not rate-limiting. Cu(I)-olefin containing binuclear ions of (NH[subscript 3])[subscript 5]Co(III)L, where L is an alkylpyridine or alkylamine, undergo efficient intramolecular electron transfer when irradiated in the Cu(I)-olefin(n*) absorption band. The results of photoredox studies of a series of alkylamine and alkylpyridine containing binuclear ions are reported. The quantum yields for Co (II) production is shown to falloff monotonically for increasing number of methylene carbons in the chain. Binuclear ions containing polyisoprenyl bridging ligands were also investigated. Mixed solvent studies show decreased quantum yield with increasing ethanol content of the aqueous media. Medium and chain configuration effects are discussed.

Errata and corrections pasted on front end paper. / Copies of three of author's previously published articles contained in back pocket. / Bibliography: leaves 178-219. / ix, 219, [130] leaves, [31] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis aims to generate a library of chromosomally derived transcriptional promoter ::lacZ fusion mutants in an environmental isolate of L. monocytogenes (DRDC8). A lacZ transcriptional fusion mutant that displayed increased B-galactosidase activity in response to the calcium chelater EGTA is investigated in detail. / Thesis (Ph.D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1997

No description available.

To Hing-lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.ii / ACKNOWLEDGMENT --- p.iii / CONTENTS --- p.iv / ABBREVIATIONS --- p.vi / Chapter CHAPTER 1 --- Synthesis and Reactivity Studies of Copper Complexes Supported by a Pyridine-Containing Ligand / Chapter 1.A. --- General Introduction / Chapter 1.A.I. --- Introduction --- p.1 / Chapter 1.A.II. --- Dioxygen Activation by Copper-Containing Species --- p.2 / Chapter 1 A.III. --- Reactivity of Copper(I) Complexes Towards Dioxygen Binding --- p.11 / Chapter 1.A.IV. --- Synthetic Models for Copper-Containing Proteins --- p.12 / Chapter 1.A.V. --- Objective of This Work --- p.27 / Results and Discussion / Chapter 1.B. --- Synthesis and Characterization / Chapter 1.B.I. --- Synthesis / Chapter 1.B.I.a. --- Ligand Synthesis --- p.28 / Chapter 1.B.I.b. --- Synthesis of Copper(I) Complexes --- p.31 / Chapter 1.B.II. --- Characterization / Chapter 1.B.II.a. --- Physical Characterization of Complex25 --- p.33 / Chapter 1.B.II.b. --- Structural Studies / Chapter 1.B.II.b.i. --- Molecular Structure of Complex25 --- p.34 / Chapter 1.B.II.b.ii. --- Comparisons of The Structural Parameters of 25 with Those of 24 and Other [Cu1(u-Br)]2 Complexes --- p.37 / Chapter 1.B.II.c. --- Electrochemical Studies --- p.38 / Chapter 1.C. --- Reactivity Studies --- p.40 / Chapter 1.D. --- Summary --- p.44 / Chapter 1.E. --- Experimental Procedures --- p.45 / Chapter 1.F. --- References --- p.54 / Chapter CHAPTER 2 --- Synthesis and Reactivity Studies of Nickel Complexes With a N3O-Donor Ligand / Chapter 2.A. --- General Introduction / Chapter 2.A.I. --- Introduction --- p.61 / Chapter 2.A.II. --- Studies of Metal-Phenoxyl Radical Arrays --- p.67 / Chapter 2.A.III. --- Objective of This Work --- p.72 / Results and Discussion / Chapter 2.B. --- Synthesis and Characterization / Chapter 2.B.I. --- Synthesis of Nickel(II) Complexes --- p.73 / Chapter 2.B.II. --- Characterization / Chapter 2.B.II.a. --- Physical Characterization of Complexes 34 and 35 --- p.75 / Chapter 2.B.II.b. --- Structural Studies / Chapter 2.B.II.b.i. --- Molecular Structure of Complex 34 --- p.75 / Chapter 2.B.II.b.ii. --- Molecular Structure of Complex 35 --- p.78 / Chapter 2.B.II.b.iii. --- Structural Comparisons --- p.81 / Chapter 2.B.II.c. --- Electrochemical Studies --- p.82 / Chapter 2.C. --- Reactivity Studies --- p.84 / Chapter 2.D. --- Summary --- p.90 / Chapter 2.E. --- Experimental Procedures --- p.91 / Chapter 2.F. --- References --- p.94 / APPENDIX A General Procedure and Physical Measurements / Chapter A.I. --- General Procedures --- p.99 / Chapter A.II. --- Physical Measurements --- p.100 / APPENDIX B Crystallographic Data / Chapter B.I. --- Selected Crystallographic Data for Compounds 25，34 and 35 --- p.102

by Chan Sau Han. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.ii / ACKNOWLEDGMENT --- p.iii / CONTENTS --- p.iv / ABBREVIATIONS --- p.vi / Chapter CHAPTER 1 --- General Introduction / Chapter 1-A. --- Role of Copper in Biology --- p.1 / Chapter 1-B. --- A Brief Review on Radical Copper Proteins --- p.4 / Chapter 1-C. --- Objectives of This Work --- p.12 / Chapter 1-D. --- References --- p.13 / Chapter CHAPTER 2 --- Copper(II) and Zinc(II) Complexes containing N3O Tetradentate Ligands / Chapter 2-A. --- Introduction Results and Discussion --- p.14 / Chapter 2-B. --- Preparation of Tetradentate Ligands and Complexes --- p.27 / Chapter 2-C. --- Characterization --- p.36 / Chapter 2-D. --- Generation of Metal Phenoxyl Radical Species --- p.51 / Chapter 2-E. --- Summary --- p.57 / Chapter 2-F. --- References --- p.59 / Chapter CHAPTER 3 --- Copper(I) Complexes with N30 Tetradentate Ligands / Chapter 3-A. --- Introduction Results and Discussion --- p.62 / Chapter 3-B. --- Preparation of Copper(I) Complexes with N30 Tetradentate Ligands --- p.75 / Chapter 3-C. --- Characterization --- p.79 / Chapter 3-D. --- Reactivities of 86，87 and 88 toward Dioxygen --- p.88 / Chapter 3-E. --- Summary --- p.93 / Chapter 3-F. --- References --- p.94 / Chapter CHAPTER 4 --- Experimental Sections / Chapter 4-A. --- General Preparations and Physical Measurements --- p.97 / Chapter 4-B. --- Compounds Described in Chapter2 --- p.99 / Chapter 4-C. --- Compounds Described in Chapter3 --- p.113 / Chapter 4-D. --- Oxo-Transfer to Triphenylphosphine as Described in Chapter3 --- p.117 / Chapter 4-E. --- References --- p.119 / Chapter APPENDIX A --- 1H and13 C̐ưث1H ̐ưحNMR Spectra / Chapter A-1. --- Compounds Described in Chapter2 --- p.120 / Chapter A-2. --- Compounds Described in Chapter3 --- p.127 / Chapter APPENDIX B --- Crystallographic Data / Chapter B-1. --- X-ray Crystal Structure Data for Complexes in Chapter2 --- p.131 / Chapter B-2. --- X-ray Crystal Structure Data for Complexes in Chapter3 --- p.133 / Chapter APPENDIX C --- GC-MS Spectra / Chapter C-1. --- GC-MS Spectra for Standard Samples --- p.134 / Chapter C-2. --- GC-MS Spectra for the Reactions with Triphenylphosphine Described in Chapter3 --- p.136