S-nitrosothiol modifications of proteins are emerging as an important nitric oxide-mediated signaling pathway. Our laboratory has focused on S-nitrosation of the metal binding protein metallothionein and the resulting effects on zinc homeostasis, gene and protein expression and nitric oxide (NO) mediated signaling in the pulmonary endothelium. Statement of public health significance: The pulmonary endothelium is responsible for filtering the blood before it enters systemic circulation, and as such it is extremely vulnerable to injury by inhaled toxicants in the environment as well as those that circulate in the bloodstream. As the endothelium constitutively produces NO, we are interested in studying NO-mediated signaling in order to lay a foundation that will allow us to better understand diseases such as asthma, pulmonary hypertension and sepsis in which dysregulation of NO-mediated signaling is thought to be a contributing factor to the disease pathology.
To this end we have used both recombinant DNA and biochemical techniques to examine the relationship between metallothionein, zinc homeostasis and the metal responsive transcription factor MTF-1. We demonstrated that exposure to NO results in zinc release from metallothionein, which in turn activates MTF-1, resulting in nuclear translocation of the protein and NO-dependent increases in metallothionein protein expression. We hypothesized that S-nitrosation of the sulphydryl groups in metallothionein were the cause of NO-mediated zinc release and downstream protein expression effects. We used a fluorescent modification of the biotin switch assay in combination with two-dimensional electrophoresis and mass spectroscopy to extend our study of NO-mediated signaling through S-nitrosation of protein thiols to identify S-nitrosated metallothionein in endothelial cells exposed to NO donor, and used the technique in further studies to illuminate the proteome of pulmonary endothelial cells. We were able to identify several potential targets of S-nitrosation in endothelial cells including cytoskeletal, cytoprotective, glycolytic and chaperone proteins. The proteomic assay that we developed is a useful screening tool, and may lead to new insights in post-translational S-nitrosothiol modifications of endothelial proteins, and eventually to new perspectives regarding diseases exacerbated by dysregulation of this NO-mediated signaling pathway.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04112008-105942 |
| Date | 26 June 2008 |
| Creators | Stitt-Fischer, Molly Sue |
| Contributors | Bruce Pitt, PhD, Claudette St. Croix, PhD, Aaron Barchowsky, PhD, Augustine Choi, MD |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04112008-105942/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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