Max F. Perutz Laboratories, Dr. Bohr-Gasse 9, 1030 Vienna
Protein quality control in the endoplasmic reticulum
Cells respond to physiological and environmental conditions that perturb the delicate balance between protein synthesis, folding and degradation. Protein-folding defects turn on stress response pathways that take corrective actions to restore homeostasis. In the endoplasmic reticulum (ER), where secretory and membrane proteins are folded and assembled, protein folding is constantly monitored by a set of signaling pathways called the unfolded protein response (UPR). In my lab, we seek to provide mechanistic details into how cells sense and respond to fluctuations in their protein-folding demands in the ER to maintain homeostasis.
*Acosta-Alvear D*, Karagöz GE*, Fröhlich F, Li H, Walther TC, Walter P. The unfolded protein response and endoplasmic reticulum protein targeting machineries converge on the stress sensor IRE1. Elife. 2018 Dec 24;7. pii: e43036. doi: 10.7554/eLife.43036. PMID: 30582518. * equal contribution.
*Karagöz, GE; Acosta-Alvear, D; Nguyen, HT; Lee, CP; Chu, F; Walter, P (2017). An unfolded protein-induced conformational switch activates mammalian IRE1. 2017 Oct 3;6. pii: e30700. doi: 10.7554/eLife.30700. PMID: 28971800
*Karagöz, GE; Duarte, AMS; Akoury, E; Ippel, H; Biernat, J; Morán Luengo, T; Radli, M; Didenko, T; Nordhues, BA; Veprintsev, DB; Dickey, CA; Mandelkow, E; Zweckstetter, M; Boelens, R; Madl, T; Rüdiger, SGD (2014). Hsp90-Tau complex reveals molecular basis for specificity in chaperone action. CELL;156(5):963-74. PMID: 24581495
Projects within VBC Ubiquitin Club
Cells respond to accumulation of unfolded proteins in the ER, where unfolded proteins with unique signatures act as activating ligands of the UPR sensors. The ER resident chaperones also bind to the sensors and regulate the response. Therefore, the interplay among chaperones, unfolded proteins and the UPR sensors together determines the magnitude and duration of the UPR. Yet, currently how ER clients with different folding demands and structural properties are recognized by the UPR sensors and how binding of chaperones to the UPR sensors and unfolded clients influences this interaction remain largely unexplored. By employing cutting-edge NMR spectroscopy approaches; biochemistry and cell biology methods, we aim to reveal the structural basis for recognition of unfolded proteins by chaperones, UPR sensors and the degradation machineries.