Myelin Basic Protein Binding Is Modulated by Leaflet Asymmetry and Lipid Composition

bioRxiv (Cold Spring Harbor Laboratory)

Abstract

Abstract Compositional asymmetry between lipid bilayer leaflets is a defining feature of biological membranes, yet its role in modulating protein binding remains largely unexplored. Here, we investigate how leaflet-specific composition affects the interaction between Myelin Basic Protein and biomimetic myelin membranes using neutron reflectometry. Asymmetric supported myelin bilayers containing deuterated cholesterol in the cytoplasmic leaflet enabled resolution of structural asymmetry. Neutron reflectometry measurements show that Myelin Basic Protein binds preferentially to asymmetric supported bilayers mimicking native myelin, whereas Experimental Autoimmune Encephalomyelitis -modified compositions exhibit weaker binding and more pronounced protein insertion. Disruption of asymmetry—either by thermal-induced lipid redistribution or by using symmetric cytoplasmic myelin—leads to a marked reduction in Myelin Basic Protein binding, despite increased membrane charge. Following vesicle adsorption and formation of a second bilayer, the protein layer narrows to near in vivo thickness in both systems, with the diseased condition exhibiting a wider inter-bilayer spacing. These results underscore the relevance of lipid asymmetry and composition in governing protein – membrane interactions, with implications for the molecular basis of myelin stability and demyelination.

Authors 11

1. Julio M. Pusterla corresponding

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungzentrum Juelich;

2. Alexandros G. Koutsioubas

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Juelich;

3. Nicoló Paracini

   European Spallation Source

   Affiliation as printed

   European Spallation Source;

4. Philipp Gutfreund

   Institut Laue-Langevin

   Affiliation as printed

   Institut Laue Langevin;

5. Maximilian W. A. Skoda

   ISIS Neutron and Muon Source

   Affiliation as printed

   ISIS Neutron and Muon Source;

6. Stephen Hall

   ISIS Neutron and Muon Source

   Affiliation as printed

   ISIS Neutron and Muon Source;

7. Igor Graf von Westarp Aachen

   RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Juelich - RWTH Aachen University;

8. Irina Apanasenko

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Juelich;

9. Marina Cagnes

   Australian Nuclear Science and Technology Organisation

   Affiliation as printed

   Australian Nuclear Science and Technology Organisation (ANSTO)

10. Stephan Foerster

    Forschungszentrum Jülich

    Affiliation as printed

    Jülich Centre for Neutron Science , Forschungszentrum Jülich GmbH , Leo-Brandt Strasse , 52428 Jülich , Germany

11. Andreas Maximilian Stadler Aachen

    RWTH Aachen University

    Affiliation as printed

    Forschungszentrum Juelich - RWTH Aachen University;