IMR Press / FBL / Volume 28 / Issue 8 / DOI: 10.31083/j.fbl2808157
Open Access Original Research
Structure of the Myelin Sheath Proteolipid Plasmolipin (PLLP) in a Ganglioside-Containing Lipid Raft
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1 Department of Biology, Faculty of Medicine, Aix-Marseille University, INSERM UMR_S 1072, Marseille, France
2 School of Medicine, University Hospital of Wales Heath Park, 14 4XN Cardiff CF, UK
3 Neuroscience Center—HiLIFE, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
*Correspondence: jacques.fantini@univ-amu.fr (Jacques Fantini)
Front. Biosci. (Landmark Ed) 2023, 28(8), 157; https://doi.org/10.31083/j.fbl2808157
Submitted: 21 March 2023 | Revised: 7 June 2023 | Accepted: 27 June 2023 | Published: 7 August 2023
(This article belongs to the Special Issue Protein Folding, Misfolding, Non-Folding, and Assembly)
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Plasmolipin (PLLP) is a membrane protein located in lipid rafts that participates in the formation of myelin. It is also implicated in many pathologies, such as neurological disorders, type 2 diabetes, and cancer metastasis. To better understand how PLLP interacts with raft components (gangliosides and cholesterol), we undertook a global study combining in silico simulations and physicochemical measurements of molecular interactions in various PLLP-ganglioside systems. Methods: In silico studies consisted of molecular dynamics simulations in reconstructed membrane environments. PLLP-ganglioside interaction measurements were performed by microtensiometry at the water-air interface on ganglioside monolayers. Results: We have elucidated the mode of interaction of PLLP with ganglioside GM1 and characterized this interaction at the molecular level. We showed that GM1 induces the structuring of the extracellular loops of PLLP and that this interaction propagates a conformational signal through the plasma membrane, involving a cholesterol molecule located between transmembrane domains. This conformational wave is finally transmitted to the intracellular domain of the protein, consistent with the role of PLLP in signal transduction. Conclusions: This study is a typical example of the epigenetic dimension of protein structure, a concept developed by our team to describe the chaperone effect of gangliosides on disordered protein motifs which associate with lipid rafts. From a physiological point of view, these data shed light on the role of gangliosides in myelin formation. From a pathological point of view, this study will help to design innovative therapeutic strategies focused on ganglioside-PLLP interactions in various PLLP-associated diseases.

Keywords
lipid rafts
ganglioside
cholesterol
neurological disorder
disease
signal transduction
plasmolipin
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