University of Oulu

Sutinen A, Paffenholz D, Nguyen GTT, Ruskamo S, Torda AE, Kursula P (2023) Conserved intramolecular networks in GDAP1 are closely connected to CMT-linked mutations and protein stability. PLoS ONE 18(4): e0284532.

Conserved intramolecular networks in GDAP1 are closely connected to CMT-linked mutations and protein stability

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Author: Sutinen, Aleksi1; Paffenholz, Dirk2; Nguyen, Giang Thi Tuyet1;
Organizations: 1Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
2Centre for Bioinformatics, University of Hamburg, Hamburg, Germany, 3 Department of Biomedicine, University of Bergen, Bergen, Norway
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.6 MB)
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Language: English
Published: Public Library of Science, 2023
Publish Date: 2023-08-11


Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral polyneuropathy in humans, and its subtypes are linked to mutations in dozens of different genes, including the gene coding for ganglioside-induced differentiation-associated protein 1 (GDAP1). The main GDAP1-linked CMT subtypes are the demyelinating CMT4A and the axonal CMT2K. Over a hundred different missense CMT mutations in the GDAP1 gene have been reported. However, despite implications for mitochondrial fission and fusion, cytoskeletal interactions, and response to reactive oxygen species, the etiology of GDAP1-linked CMT is poorly understood at the protein level. Based on earlier structural data, CMT-linked mutations could affect intramolecular interaction networks within the GDAP1 protein. We carried out structural and biophysical analyses on several CMT-linked GDAP1 protein variants and describe new crystal structures of the autosomal recessive R120Q and the autosomal dominant A247V and R282H GDAP1 variants. These mutations reside in the structurally central helices ⍺3, ⍺7, and ⍺8. In addition, solution properties of the CMT mutants R161H, H256R, R310Q, and R310W were analysed. All disease variant proteins retain close to normal structure and solution behaviour. All mutations, apart from those affecting Arg310 outside the folded GDAP1 core domain, decreased thermal stability. In addition, a bioinformatics analysis was carried out to shed light on the conservation and evolution of GDAP1, which is an outlier member of the GST superfamily. GDAP1-like proteins branched early from the larger group of GSTs. Phylogenetic calculations could not resolve the exact early chronology, but the evolution of GDAP1 is roughly as old as the splits of archaea from other kingdoms. Many known CMT mutation sites involve conserved residues or interact with them. A central role for the ⍺6-⍺7 loop, within a conserved interaction network, is identified for GDAP1 protein stability. To conclude, we have expanded the structural analysis on GDAP1, strengthening the hypothesis that alterations in conserved intramolecular interactions may alter GDAP1 stability and function, eventually leading to mitochondrial dysfunction, impaired protein-protein interactions, and neuronal degeneration.

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Series: PLoS one
ISSN: 1932-6203
ISSN-E: 1932-6203
ISSN-L: 1932-6203
Volume: 18
Issue: 4
Article number: e0284532
DOI: 10.1371/journal.pone.0284532
Type of Publication: A1 Journal article – refereed
Field of Science: 1182 Biochemistry, cell and molecular biology
Funding: This work was funded by the Academy of Finland, project number 24302881 (PK). The SAXS and SRCD experiments were supported by CalipsoPlus, which is funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 730872 (PK). SRCD experiments further received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 101004806 (MOSBRI-2021-24) (AS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Copyright information: © 2023 Sutinen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.