title: Lipid Selectivity, Orientation, and Extent of Membrane Binding of Nonacylated RP2.
abstract: Retinitis pigmentosa 2 (RP2) is an ubiquitary protein of 350 residues. The N-terminus of RP2 contains putative sites of myristoylation and palmitoylation. The dually acylated protein is predominantly localized to the plasma membrane. However, clinically occurring substitution mutations of RP2 in photoreceptors lead to the expression of a nonacylated protein, which was shown to be misrouted to intracellular organelles using different cell lines. However, the parameters responsible for the modulation of the membrane binding of nonacylated RP2 (naRP2) are still largely unknown. The maximal insertion pressure of naRP2 has thus been determined after its injection into the subphase underneath monolayers of phospholipids, which are typical of photoreceptor membranes. These data demonstrated that naRP2 shows a preferential binding to saturated phospholipid monolayers. Moreover, polarization modulation infrared reflection absorption spectroscopy has allowed comparison of the secondary structure of this protein in solution and upon binding to phospholipid monolayers. In addition, simulations of these spectra have allowed to determine that the β-helix of naRP2 has an orientation of 60° with respect to the normal, which remains unchanged regardless of the type of phospholipid. Finally, ellipsometric measurements of naRP2 demonstrated that its particular affinity for saturated phospholipids can be explained by its larger extent of insertion in this phospholipid monolayer compared to that in polyunsaturated phospholipid monolayers.
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Éric
authors.initials: É
authors.lastname: Demers
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Élodie
authors.initials: É
authors.lastname: Boisselier
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Habib
authors.initials: H
authors.lastname: Horchani
authors.affiliation: ‡CBMN-UMR 5248 CNRS, Université de Bordeaux, IPB, Allée Geoffroy Saint Hilaire, 33600 Pessac, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Blaudez
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Calvez
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Line
authors.initials: L
authors.lastname: Cantin
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Belley
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Sophie
authors.initials: S
authors.lastname: Champagne
authors.affiliation: ‡CBMN-UMR 5248 CNRS, Université de Bordeaux, IPB, Allée Geoffroy Saint Hilaire, 33600 Pessac, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Desbat
authors.affiliation: †CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Salesse
mesh_terms: D000215:Acylation; D019943:Amino Acid Substitution; D005136:Eye Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D054878:Lipoylation; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008567:Membranes, Artificial; D020125:Mutation, Missense; D010743:Phospholipids / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary
chemical_list: D005136:Eye Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008567:Membranes, Artificial; D010743:Phospholipids; C072178:RP2 protein, human; D019204:GTP-Binding Proteins