Non-canonical Shedding of TNFα by SPPL2a Is Determined by the Conformational Flexibility of Its Transmembrane Helix

iScience

Charlotte Spitz¹  Christine Schlosser¹  Regina Fluhrer¹  Martina Haug-Kröper¹  Claudia Muhle-Goll²  Nadja Guschtschin-Schmidt²  Dieter Langosch³  Walter Stelzer³  Christina Scharnagl⁴  Simon Menig⁴  Alexander Götz⁵ 

[1] Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstrasse 2, 86159 Augsburg, Germany;Karlsruhe Institute of Technology, Institute for Biological Interfaces 4, 76344 Eggenstein- Leopoldshafen, Germany and Karlsruhe Institute of Technology, Institute of Organic Chemistry, 76131 Karlsruhe, Germany;Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany;Physics of Synthetic Biological Systems, Technische Universität München, Maximus-von-Imhof Forum 4, 85340 Freising, Germany;Present Address: Leibniz Supercomputing Centre, Boltzmannstr. 1, 85748 Garching, Germany;

关键词: Biochemistry;    Structural Biology;    Biophysics;   

DOI  :  

来源: DOAJ

【 摘 要 】

Summary: Ectodomain (EC) shedding defines the proteolytic removal of a membrane protein EC and acts as an important molecular switch in signaling and other cellular processes. Using tumor necrosis factor (TNF)α as a model substrate, we identify a non-canonical shedding activity of SPPL2a, an intramembrane cleaving aspartyl protease of the GxGD type. Proline insertions in the TNFα transmembrane (TM) helix strongly increased SPPL2a non-canonical shedding, while leucine mutations decreased this cleavage. Using biophysical and structural analysis, as well as molecular dynamic simulations, we identified a flexible region in the center of the TNFα wildtype TM domain, which plays an important role in the processing of TNFα by SPPL2a. This study combines molecular biology, biochemistry, and biophysics to provide insights into the dynamic architecture of a substrate's TM helix and its impact on non-canonical shedding. Thus, these data will provide the basis to identify further physiological substrates of non-canonical shedding in the future.

【 授权许可】

Unknown