Research Terms
Life Sciences Biochemistry Enzymes Proteins Cell Biology Molecular Genetics Microbiology Bacteriology Molecular Biology Parasitology Molecular Parasitology Structural Biology Biophysics Biomedicine Bacterial and Fungal Diseases Parasitic Diseases Pharmacology Pharmacokinetics
Keywords
AAA proteins Cysteine protease Deubiquitinating enzyme Deubiquitinating Enzymes Immunoproteasome Intracellular parasite Microsporidia Obligate parasite Parasite Polyubiquitin Chains Proteasome Proteasome Inhibitors Proteasomes Ubiquitin
Industries
Dr. Tomko completed his graduate studies in pharmacology at the University Of Pittsburgh School Of Medicine’s Drug Discovery Institute, where he became familiar with modern drug discovery and development. His thesis work probing the regulation of a short-lived protein sparked his interest in the cell’s machinery to recycle damaged or unneeded proteins. To pursue this interest, he moved to Yale University, where he was an American Cancer Society Postdoctoral Fellow in the Department of Molecular Biophysics and Biochemistry. As a postdoctoral fellow, Robert made several seminal discoveries regarding the assembly of the proteasome, a large, multisubunit protease complex that executes most of the cell’s regulatory and quality control protein degradation. In 2015, Dr. Tomko joined the faculty of Biomedical Sciences at FSU, where his group studies the structure and function of ubiquitin-proteasome system components and their manipulation by parasites that cause rare infectious diseases in humans. His laboratory works on the scale of individual proteins up to whole cells, and integrates approaches spanning biochemistry, cell biology, genetics, structural biology, proteomics, biophysics, and pharmacology. Ultimately, his group aims to utilize the information gained from these basic studies of the ubiquitin-proteasome system to identify new targets and develop pharmacological modulators with potential thereapeutic benefit.
Journal of Biological Chemistry, Board of Advisors; 2021 - present
This technology involves chimeric proteins having deubiquitinase activity and methods of identifying anti-deubiquitinase compounds using the chimeric proteins. These methods and assays can be adapted to high throughput screening procedures to assay for anti-cancer drugs effecting deubiquitinase activity. Disrupting the Rpn11 deubiquitinase function is a validated strategy for treatment of human cancers.
The assay utilizes a collection of genetically modified yeast strains producing a chimeric human proteasomal Rpn11 deubiquitinase. In baker’s yeast, deletion of the endogenous yeast Rpn11 gene is lethal, but inhibition of Rpn11 deubiquitinating activity is not. Inhibition of Rpn11 activity is lethal only when a second deubiquitinase, UBP6 (USP14 in humans), is deleted. Importantly, this synthetic lethal relationship is maintained in yeast harboring hRpn11. Thus, a selective inhibitor of human Rpn11 would be lethal in the hRpn11 strain lacking UBP6, but nontoxic in a strain containing UBP6 and harboring inactivating point mutations in hRpn11.By measuring cell growth in the presence of potential inhibitors using any commercially available plate reader, a high throughput cell-based screen for compounds selectively inhibiting hRpn11 can be enacted.
