Jaeckl, Magnus and Stollmaier, Carsten and Strohaeker, Timo and Hyz, Karolina and Maspero, Elena and Polo, Simona and Wiesner, Silke (2018) beta-Sheet Augmentation Is a Conserved Mechanism of Priming HECT E3 Ligases for Ubiquitin Ligation. JOURNAL OF MOLECULAR BIOLOGY, 430 (18). pp. 3218-3233. ISSN 0022-2836, 1089-8638
Full text not available from this repository. (Request a copy)Abstract
Ubiquitin (Ub) ligases (E3s) catalyze the attachment of Ub chains to target proteins and thereby regulate a wide array of signal transduction pathways in eukaryotes. In HECT-type E3s, Ub first forms a thioester intermediate with a strictly conserved Cys in the C-lobe of the HECT domain and is then ligated via an isopeptide bond to a Lys residue in the substrate or a preceding Ub in a poly-Ub chain. To date, many key aspects of HECT-mediated Ub transfer have remained elusive. Here, we provide structural and functional insights into the catalytic mechanism of the HECT-type ligase Huwe1 and compare it to the unrelated, K63-specific Smurf2 E3, a member of the Nedd4 family. We found that the Huwe1 HECT domain, in contrast to Nedd4-family E3s, prioritizes K6- and K48-poly-Ub chains and does not interact with Ub in a non-covalent manner. Despite these mechanistic differences, we demonstrate that the architecture of the C-lobe Ub intermediate is conserved between Huwe1 and Smurf2 and involves a reorientation of the very C-terminal residues. Moreover, in Nedd4 E3s and Huwe1, the individual sequence composition of the Huwe1 C-terminal tail modulates ubiquitination activity, without affecting thioester formation. In sum, our data suggest that catalysis of HECT ligases hold common features, such as the 13-sheet augmentation that primes the enzymes for ligation, and variable elements, such as the sequence of the HECT C-terminal tail, that fine-tune ubiquitination activity and may aid in determining Ub chain specificity by positioning the substrate or acceptor Ub. (C) 2018 Elsevier Ltd. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TUMOR-SUPPRESSOR; DOMAIN; INSIGHTS; COMPLEX; PROTEIN; CHAIN; POLYUBIQUITIN; REVEALS; HUWE1; AUTOINHIBITION; Huwe1; Smurf2; HECT domain; thioester intermediate; NMR spectroscopy |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 13 Dec 2019 08:17 |
| Last Modified: | 13 Dec 2019 08:17 |
| URI: | https://pred.uni-regensburg.de/id/eprint/13861 |
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