title: Transbilayer asymmetry and sphingomyelin composition modulate the preferential membrane partitioning of the nicotinic acetylcholine receptor in Lo domains.
abstract: We have previously shown that the intact nicotinic acetylcholine receptor (AChR) lacks preference for Lo domains when reconstituted in a sphingomyelin (SM), cholesterol (Chol) and POPC (1:1:1) model system (Bermúdez V, Antollini SS, Fernández-Nievas GA, Aveldaño MI, Barrantes FJ. J. Lipid Res. 2010; 51: 2629-2641). Here, we have furthered our studies by characterizing the influence of different lipid host compositions on the distribution of purified AChR reconstituted in two model systems (POPC:Chol, 1:1 and POPC:Chol:SM, 1:1:1), involving a) different SM species (porcine brain SM (bSM), 16:0-SM, 18:0-SM or 24:1-SM); or b) induced transbilayer asymmetry, resulting from enrichment in bSM in the external hemilayer. AChR distribution was evaluated by fluorescence resonance energy transfer efficiency between the AChR intrinsic fluorescence and Laurdan or dehydroergosterol fluorescence, and by analyzing the distribution of AChR in detergent-resistant and detergent-soluble fractions (1% Triton X-100, 4 °C). bSM-induced transbilayer asymmetry or the presence of 16:0-SM and/or 18:0-SM (unlike bSM or 24:1-SM) resulted in the preferential partitioning of AChR in Lo domains, suggesting that the localization of AChR in ordered domains strongly depends on the characteristics of the host lipid membrane, and in particular on the sphingolipid composition and transbilayer asymmetry.
authors.affiliation: Instituto de Investigaciones Bioquímicas de Bahía Blanca (CONICET-UNS), Camino La Carringanda Km 7, 8000 Bahía Blanca, Buenos Aires, Argentina; Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina.
authors.forename: Vanesa L
authors.initials: VL
authors.lastname: Perillo
authors.affiliation: Instituto de Investigaciones Bioquímicas de Bahía Blanca (CONICET-UNS), Camino La Carringanda Km 7, 8000 Bahía Blanca, Buenos Aires, Argentina; Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Peñalva
authors.affiliation: Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina; Instituto Argentino de Oceanografía (CONICET-UNS), Camino La Carringanda Km 7, 8000 Bahía Blanca, Buenos Aires, Argentina.
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Vitale
authors.affiliation: Laboratory of Molecular Neurobiology, BIOMED UCA-CONICET, Av Moreau de Justo 1300, 1107 Buenos Aires, Argentina.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Barrantes
authors.affiliation: Instituto de Investigaciones Bioquímicas de Bahía Blanca (CONICET-UNS), Camino La Carringanda Km 7, 8000 Bahía Blanca, Buenos Aires, Argentina; Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina. Electronic address: silviant@criba.edu.ar.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Antollini
mesh_terms: D001665:Binding Sites; D008051:Lipid Bilayers / Q000737:chemistry*; D008560:Membrane Fluidity; D021962:Membrane Microdomains / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011978:Receptors, Nicotinic / Q000737:chemistry*; D013109:Sphingomyelins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D011978:Receptors, Nicotinic; D013109:Sphingomyelins
keywords: Fluorescence; Lipid raft; Liposomes; Nicotinic acetylcholine receptors; Sphingolipids; Transbilayer asymmetry