title: The C2 domains of otoferlin, dysferlin, and myoferlin alter the packing of lipid bilayers.
abstract: Ferlins are large multi-C2 domain membrane proteins involved in membrane fusion and fission events. In this study, we investigate the effects of binding of the C2 domains of otoferlin, dysferlin, and myoferlin on the structure of lipid bilayers. Fluorescence measurements indicate that multi-C2 domain constructs of myoferlin, dysferlin, and otoferlin change the lipid packing of both small unilamellar vesicles and giant plasma membrane vesicles. The activities of these proteins were enhanced in the presence of calcium and required negatively charged lipids like phosphatidylserine or phosphatidylglycerol for activity. Experiments with individual domains uncovered functional differences between the C2A domain of otoferlin and those of dysferlin and myoferlin, and truncation studies suggest that the effects of each subsequent C2 domain on lipid ordering appear to be additive. Finally, we demonstrate that the activities of these proteins on membranes are insensitive to high salt concentrations, suggesting a nonelectrostatic component to the interaction between ferlin C2 domains and lipid bilayers. Together, the data indicate that dysferlin, otoferlin, and myoferlin do not merely passively adsorb to membranes but actively sculpt lipid bilayers, which would result in highly curved or distorted membrane regions that could facilitate membrane fusion, membrane fission, or recruitment of other membrane-trafficking proteins.
authors.affiliation: Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Marty
authors.forename: Chelsea L
authors.initials: CL
authors.lastname: Holman
authors.forename: Nazish
authors.initials: N
authors.lastname: Abdullah
authors.forename: Colin P
authors.initials: CP
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D000073939:Dysferlin; D004591:Electrophoresis, Polyacrylamide Gel; D057809:HEK293 Cells; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009124:Muscle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000737:chemistry / Q000378:metabolism; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D053835:Unilamellar Liposomes / Q000737:chemistry / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; C114839:DYSF protein, human; D000073939:Dysferlin; D008051:Lipid Bilayers; C415584:MYOF protein, human; D008563:Membrane Lipids; D008565:Membrane Proteins; D009124:Muscle Proteins; C118457:OTOF protein, human; D010715:Phosphatidylglycerols; D010718:Phosphatidylserines; D011994:Recombinant Proteins; D053835:Unilamellar Liposomes