Experimental and Computational Analysis of Newly Identified Pathogenic Mutations in the Creatine Transporter SLC6A8
- Author(s)
- Evandro Ferrada, Tabea Wiedmer, Wen An Wang, Fabian Frommelt, Barbara Steurer, Christoph Klimek, Sabrina Lindinger, Tanja Osthushenrich, Andrea Garofoli, Silvia Brocchetti, Samuel Bradberry, Jiahui Huang, Aidan MacNamara, Lia Scarabottolo, Gerhard F. Ecker, Anders Malarstig, Giulio Superti-Furga
- Abstract
Creatine is an essential metabolite for the storage and rapid supply of energy in muscle and nerve cells. In humans, impaired metabolism, transport, and distribution of creatine throughout tissues can cause varying forms of mental disability, also known as creatine deficiency syndrome (CDS). So far, 80 mutations in the creatine transporter (SLC6A8) have been associated to CDS. To better understand the effect of human genetic variants on the physiology of SLC6A8 and their possible impact on CDS, we studied 30 missense variants including 15 variants of unknown significance, two of which are reported here for the first time. We expressed these variants in HEK293 cells and explored their subcellular localization and transport activity. We also applied computational methods to predict variant effect and estimate site-specific changes in thermodynamic stability. To explore variants that might have a differential effect on the transporter's conformers along the transport cycle, we constructed homology models of the inward facing, and outward facing conformations. In addition, we used mass-spectrometry to study proteins that interact with wild type SLC6A8 and five selected variants in HEK293 cells. In silico models of the protein complexes revealed how two variants impact the interaction interface of SLC6A8 with other proteins and how pathogenic variants lead to an enrichment of ER protein partners. Overall, our integrated analysis disambiguates the pathogenicity of 15 variants of unknown significance revealing diverse mechanisms of pathogenicity, including two previously unreported variants obtained from patients suffering from the creatine deficiency syndrome.
- Organisation(s)
- Department of Pharmaceutical Sciences
- External organisation(s)
- Bayer AG, Axxam SpA, Pfizer Worldwide Research, Medizinische Universität Wien, Österreichische Akademie der Wissenschaften (ÖAW)
- Journal
- Journal of Molecular Biology
- Volume
- 436
- No. of pages
- 24
- ISSN
- 0022-2836
- DOI
- https://doi.org/10.1016/j.jmb.2023.168383
- Publication date
- 01-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 301207 Pharmaceutical chemistry
- Keywords
- ASJC Scopus subject areas
- Biophysics, Structural Biology, Molecular Biology
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/experimental-and-computational-analysis-of-newly-identified-pathogenic-mutations-in-the-creatine-transporter-slc6a8(2ab4c998-f49e-4051-bfa3-66702bb60aab).html