A number of new principles are emerging from the study of inorganic physiology, including the idea that intracellular metals such as zinc, copper and iron are not 'trace elements'from a cellular point of view, but are routinely maintained in most cells at much higher levels (i.e., 0.6 mM). These insights, as well as the emerging literature linking metal physiology to many disease states underscore the importance of establishing the fundamental principles governing cellular metal ion regulation. Our approach to delineating these new principles involves mechanistic and structural characterization of metal receptors that switch on and off genes in a metal dependent manner. This proposal specifically focuses on how such metalloregulatory proteins control the transcriptional machinery to achieve specific types of physiological switching events. Preliminary studies reveal the first crystal structures for metal-responsive members of the MerR and Fur family proteins bound to their DNA targets, namely CueR/DNA and Zur/DNA. The new results raise a significant number of questions about how these proteins control intracellular metal ion homeostasis.
The specific aims are to resolve key, unanticipated questions about the structures, functions and molecular mechanisms of these metalloregulatory proteins. The proposed experiments will employ x-ray crystallography, biophysical methods and single particle electron microscopy to understand how metal binding to the regulatory protein induces conformational changes across the promoter complex with RNA polymerase and leads to changes in gene expression. This approach will enable us to understand how metal-binding events are communicated through explicit protein and nucleic acid conformation changes into a direct effect on polymerase activity. The effects of these biophysical switching mechanisms on intracellular metal physiology will then be examined using novel single cell analytical methods with the overarching goal of establishing general principles and mechanisms that control metal ion homeostasis in normal and disease states.
This proposal focuses on the fundamental ways in which living cells sense and control the amount of essential nutrient metals such as copper zinc and iron. For instance, when cells need more metal, some of these sensors work by turning on metal uptake machinery, and when cells need to get rid of excess metal, other sensors work to turn on machinery that ejects metals from the cell. This control is important because an imbalance in cellular metal can lead to diseases involving infectious agents, liver disorders, diabetes and brain function.
|Mendoza, Adelita D; Woodruff, Teresa K; Wignall, Sarah M et al. (2017) Zinc availability during germline development impacts embryo viability in Caenorhabditis elegans. Comp Biochem Physiol C Toxicol Pharmacol 191:194-202|
|Que, Emily L; Duncan, Francesca E; Bayer, Amanda R et al. (2017) Zinc sparks induce physiochemical changes in the egg zona pellucida that prevent polyspermy. Integr Biol (Camb) 9:135-144|
|Deng, Junjing; Hong, Young Pyo; Chen, Si et al. (2017) Nanoscale x-ray imaging of circuit features without wafer etching. Phys Rev B 95:|
|Staehlin, Benjamin M; Gibbons, John G; Rokas, Antonis et al. (2016) Evolution of a Heavy Metal Homeostasis/Resistance Island Reflects Increasing Copper Stress in Enterobacteria. Genome Biol Evol 8:811-26|
|Que, Emily L; Bleher, Reiner; Duncan, Francesca E et al. (2015) Quantitative mapping of zinc fluxes in the mammalian egg reveals the origin of fertilization-induced zinc sparks. Nat Chem 7:130-9|
|Philips, Steven J; Canalizo-Hernandez, Monica; Yildirim, Ilyas et al. (2015) TRANSCRIPTION. Allosteric transcriptional regulation via changes in the overall topology of the core promoter. Science 349:877-81|
|Yildirim, Ilyas; Chakraborty, Debayan; Disney, Matthew D et al. (2015) Computational investigation of RNA CUG repeats responsible for myotonic dystrophy 1. J Chem Theory Comput 11:4943-58|
|Kong, Betty Y; Duncan, Francesca E; Que, Emily L et al. (2015) The inorganic anatomy of the mammalian preimplantation embryo and the requirement of zinc during the first mitotic divisions. Dev Dyn 244:935-47|
|Hong, Young Pyo; Gleber, Sophie-Charlotte; O'Halloran, Thomas V et al. (2014) Alignment of low-dose X-ray fluorescence tomography images using differential phase contrast. J Synchrotron Radiat 21:229-34|
|Gilston, Benjamin A; Wang, Suning; Marcus, Mason D et al. (2014) Structural and mechanistic basis of zinc regulation across the E. coli Zur regulon. PLoS Biol 12:e1001987|
Showing the most recent 10 out of 25 publications