Abstract
Dystrophin is essential to skeletal muscle function and confers resistance to the sarcolemma by interacting with cytoskeleton and membrane. In the present work, we characterized the behavior of dystrophin 11-15 (DYS R11-15), five spectrin-like repeats from the central domain of human dystrophin, with lipids. DYS R11-15 displays an amphiphilic character at the liquid/air interface while maintaining its secondary α-helical structure. The interaction of DYS R11-15 with small unilamellar vesicles (SUVs) depends on the lipid nature, which is not the case with large unilamellar vesicles (LUVs). In addition, switching from anionic SUVs to anionic LUVs suggests the lipid packing as a crucial factor for the interaction of protein and lipid. The monolayer model and the modulation of surface pressure aim to mimic the muscle at work (i.e. dynamic changes of muscle membrane during contraction and relaxation) (high and low surface pressure). Strikingly, the lateral pressure modifies the protein organization. Increasing the lateral pressure leads the proteins to be organized in a regular network. Nevertheless, a different protein conformation after its binding to monolayer is revealed by trypsin proteolysis. Label-free quantification by nano-LC/MS/MS allowed identification of the helices in repeats 12 and 13 involved in the interaction with anionic SUVs. These results, combined with our previous studies, indicate that DYS R11-15 constitutes the only part of dystrophin that interacts with anionic as well as zwitterionic lipids and adapts its interaction and organization depending on lipid packing and lipid nature. We provide strong experimental evidence for a physiological role of the central domain of dystrophin in sarcolemma scaffolding through modulation of lipid-protein interactions.
Highlights
Residues in boldface type indicate the start (N terminus column) or end (C terminus column) residue of the repeat from the alignment of Winder et al [13]
Because it is known that the surface pressure of a monolayer can induce different binding properties for amphiphilic proteins by favoring electrostatic and hydrophobic forces, we examined the adsorption of DYS R11–15 to phospholipid anionic and zwitterionic monolayers at various initial surface pressures (i)
We focused on the behavior of the central domain repeats of dystrophin
Summary
A The DYS R11–15 (residues 1–515) protein used in this study corresponds to residues 1461–1973 of native full-length dystrophin. To investigate the impacts of lipid packing and lipid composition on DYS R11–15 function, we characterized the interaction and the organization of DYS R11–15 with two lipid mixtures, 1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPC/ DOPS) (1:1) and 1,2-dioleoyl-sn-glycero-3-phosphocholine: 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPC/ DOPE) (1/1), in vesicles (SUVs and LUVs) and monolayer lipid membrane models. These lipids were chosen because of their presence in the sarcolemma [12], where DO fatty acids constitute 12% of the global membrane composition. We used DOPC/DOPS or DOPC/DOPE lipid mixtures at a 1:1 ratio (mol/mol) because phosphatidylcholine represents ϳ45%, phosphatidylethanolamine 23%, and phosphatidylserine 18% of the total phospholipids and to enhance potential specific effects of phosphatidylethanolamine compared with PS
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
