title: Palmitoylation of cysteine 415 of CB1receptor affects ligand-stimulated internalization and selective interaction with membrane cholesterol and caveolin 1.
abstract: We previously demonstrated that CB1receptor is palmitoylated at cysteine 415, and that such a post-translational modification affects its biological activity. To assess the molecular mechanisms responsible for modulation of CB1receptor function by S-palmitoylation, in this study biochemical and morphological approaches were paralleled with computational analyses. Molecular dynamics simulations suggested that this acyl chain stabilizes helix 8 as well as the interaction of CB1receptor with membrane cholesterol. In keeping with these in silico data, experimental results showed that the non-palmitoylated CB1receptor was unable to interact efficaciously with caveolin 1, independently of its activation state. Moreover, in contrast with the wild-type receptor, the lack of S-palmitoylation in the helix 8 made the mutant CB1receptor completely irresponsive to agonist-induced effects in terms of both lipid raft partitioning and receptor internalization. Overall, our results support the notion that palmitoylation of cysteine 415 modulates the conformational state of helix 8 and influences the interactions of CB1receptor with cholesterol and caveolin 1, suggesting that the palmitoyl chain may serve as a functional interface for CB1receptor localization and function.
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy; European Center for Brain Research (CERC)/Santa Lucia Foundation IRCCS, Rome, Italy. Electronic address: soddi@unite.it.
authors.forename: Sergio
authors.initials: S
authors.lastname: Oddi
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF), Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain; Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland.
authors.forename: Tomasz Maciej
authors.initials: TM
authors.lastname: Stepniewski
authors.affiliation: European Center for Brain Research (CERC)/Santa Lucia Foundation IRCCS, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Totaro
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF), Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain.
authors.forename: Jana
authors.initials: J
authors.lastname: Selent
authors.affiliation: European Center for Brain Research (CERC)/Santa Lucia Foundation IRCCS, Rome, Italy; Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Scipioni
authors.affiliation: Faculty of Bioscience and Technology for Food Agriculture and Environment, University of Teramo, Teramo, Italy.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Dufrusine
authors.affiliation: European Center for Brain Research (CERC)/Santa Lucia Foundation IRCCS, Rome, Italy; Department of Experimental Medicine and Surgery, Tor Vergata University of Rome, Rome, Italy.
authors.forename: Filomena
authors.initials: F
authors.lastname: Fezza
authors.affiliation: European Center for Brain Research (CERC)/Santa Lucia Foundation IRCCS, Rome, Italy; Faculty of Bioscience and Technology for Food Agriculture and Environment, University of Teramo, Teramo, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Dainese
authors.affiliation: European Center for Brain Research (CERC)/Santa Lucia Foundation IRCCS, Rome, Italy; Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy. Electronic address: m.maccarrone@unicampus.it.
authors.forename: Mauro
authors.initials: M
authors.lastname: Maccarrone
mesh_terms: D051242:Caveolin 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism*; D003545:Cysteine / Q000737:chemistry / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D054878:Lipoylation / Q000235:genetics; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D009154:Mutation; D019308:Palmitic Acid / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D060066:Protein Interaction Maps / Q000235:genetics; D043884:Receptor, Cannabinoid, CB1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; D008024:Ligands; D043884:Receptor, Cannabinoid, CB1; D019308:Palmitic Acid; D002784:Cholesterol; D003545:Cysteine
keywords: Caveolae; Homology modeling; Lipid rafts; Molecular dynamics; Receptor acylation; Type-1 cannabinoid receptor