The selective degradation of intracellular proteins is of central importance for the generation, function and survival of eukaryotic cells. The ubiquitin-proteasome system (UPS) is responsible for the controlled degradation of most intracellular proteins, and abnormal regulation of the UPS is associated with a variety of human diseases, including cancer, myopathies, and neurodegenerative disorders. Although dramatic progress has been made in understanding the structure and function of proteasomes, we still know extremely little about how proteasome activity is dynamically regulated in time and space. The activity of the 26S proteasome declines with age, but the underlying molecular mechanisms remain unknown. Our prior work focused on the regulation of caspases by the UPS, and results obtained during the current funding cycle revealed the joint use of proteasomes and caspases in the "controlled demolition" of cellular structures that is needed for terminal sperm differentiatio in Drosophila. Similar mechanisms are thought to mediate the remodeling of other cell types, including neurons and muscle, in both insects and vertebrates. The overall goal of this project is to understand how proteasomes are regulated to promote changes in the cyto architecture, size and survival of cells, and how this process affects age-related neuronal degeneration. We recently discovered a novel proteasome regulatory mechanism that offers unique opportunities to study proteasome regulation in the context of both normal organismal development, and in response to stress and aging. In particular, we found that the ADP-ribosyl transferase Tankyrase (TNKS) binds to and critically activates the proteasome regulator PI31 (Proteasome Inhibitor of 31kDa) to promote 26S proteasome assembly. These results suggest a potential mechanistic link between energy metabolism, NAD+, DNA-damage and proteasome regulation that is likely to play important roles in development, protein homeostasis and aging. Here, we will investigate the biological role and regulation of TNKS/PI31-mediated proteasome activation. We propose to use a multi-disciplinary approach that integrates Drosophila genetics, developmental biology, cell biology, and neurobiology, biochemistry, and small- molecule chemical inhibitors. Amongst other things, we will test the specific hypotheses that the TNKS/PI31-pathway is regulated by NAD+ that activation of this pathway protects against phototoxic stress and that diminished activity of this pathway with age causes increased vulnerability to neuronal degeneration. The current proposal brings, for the first time, the full power of Drosophila genetics and molecular biology to investigate these questions and combines it with biochemical studies in both insect and mammalian cells to explore new paths towards the clinic. We expect that this project will fundamentally advance our understanding of how protein degradation is regulated and provide new insights how to manipulate this process for the treatment of human diseases.
The proteasome is a validated anti-cancer target, and the proteasome inhibitor bortezomib (Velcade) is clinically used for the treatment of multiple myeloma and mantle cell lymphoma. On the other hand, many age-related diseases are caused by phototoxic stress due to insufficient degradation of abnormal proteins, including neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's disease. The proposed project will provide fundamental new insights and tools to better understand how proteasome activity can be manipulated to treat human diseases, including cancer, neuronal degeneration and other age-related ailments.
|Minis, Adi; Steller, Hermann (2016) Krebs Cycle Moonlights in Caspase Regulation. Dev Cell 37:1-2|
|Soteriou, Despina; Kostic, Lana; Sedov, Egor et al. (2016) Isolating Hair Follicle Stem Cells and Epidermal Keratinocytes from Dorsal Mouse Skin. J Vis Exp :|
|Rosas-Arellano, Abraham; VÃ¡squez-Procopio, Johana; Gambis, Alexis et al. (2016) Ferritin Assembly in Enterocytes of Drosophila melanogaster. Int J Mol Sci 17:27|
|Mollereau, B; Rzechorzek, N M; Roussel, B D et al. (2016) Adaptive preconditioning in neurological diseases - therapeutic insights from proteostatic perturbations. Brain Res 1648:603-616|
|Steller, Hermann (2015) Preface. Curr Top Dev Biol 114:xv-xvi|
|Kim, A-Young; Seo, Jong Bok; Kim, Won-Tae et al. (2015) The pathogenic human Torsin A in Drosophila activates the unfolded protein response and increases susceptibility to oxidative stress. BMC Genomics 16:338|
|PÃ©rez-Garijo, Ainhoa; Steller, Hermann (2015) Spreading the word: non-autonomous effects of apoptosis during development, regeneration and disease. Development 142:3253-62|
|Fuchs, Yaron; Steller, Hermann (2015) Live to die another way: modes of programmed cell death and the signals emanating from dying cells. Nat Rev Mol Cell Biol 16:329-44|
|Sandu, Cristinel; Chandramouli, Nagaranjan; Glickman, Joseph Fraser et al. (2015) Thiostrepton interacts covalently with Rpt subunits of the 19S proteasome and proteasome substrates. J Cell Mol Med 19:2181-92|
|Sandu, Cristinel; Ngounou Wetie, Armand G; Darie, Costel C et al. (2014) Thiostrepton, a natural compound that triggers heat shock response and apoptosis in human cancer cells: a proteomics investigation. Adv Exp Med Biol 806:443-51|
Showing the most recent 10 out of 38 publications