title: Fatty acid composition of Drosophila photoreceptor light-sensitive microvilli.
abstract: Phototransduction, the mechanism underlying the electrical response to light in photoreceptor cells, has been thoroughly investigated in Drosophila melanogaster, an essential model in signal transduction research. These cells present a highly specialized photosensitive membrane consisting of thousands of microvilli forming a prominent structure termed a rhabdomere. These microvilli encompass the phototransduction proteins, most of which are transmembrane and exclusively rhabdomeric. Rhabdomere membrane lipids play a crucial role in the activation of the transient receptor potential ionic channels (TRP and TRPL) responsible for initiating the photoresponse. Despite its importance, rhabdomere lipid composition has not been established. We developed a novel preparation enriched in rhabdomere membranes to perform a thorough characterization of the lipidomics of Drosophila rhabdomeres. Isolated eyes (500) were homogenized and subjected to a differential centrifugation protocol that generates a fraction enriched in rhabdomere membrane. Lipids extracted from this preparation were identified and quantified by gas chromatography coupled to mass spectrometry. We found an abundance of low sterol esters (C16:0, C18:0), highly abundant and diverse triglycerides, free fatty acids, a moderate variety of mono and diacyglycerols (C:16:0, 18:0, C18:1) and abundant phospholipids (principally C18:2). This preparation opens a new avenue for investigating essential aspects of phototransduction.
authors.affiliation: Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile, rdelgado@uchile.cl.
authors.forename: Yorka
authors.initials: Y
authors.lastname: Muñoz
authors.affiliation: Faculty of Biological Sciences, Pontifical Catholic University of Chile, Santiago, Chile.
authors.forename: Karen
authors.initials: K
authors.lastname: Fuenzalida
authors.affiliation: Faculty of Biological Sciences, Pontifical Catholic University of Chile, Santiago, Chile.
authors.forename: Miguel
authors.initials: M
authors.lastname: Bronfman
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile.
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Gatica
authors.affiliation: Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile, rdelgado@uchile.cl.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Sepúlveda
authors.affiliation: Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile, rdelgado@uchile.cl.
authors.forename: Juan
authors.initials: J
authors.lastname: Bacigalupo
authors.affiliation: Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile, rdelgado@uchile.cl.
authors.forename: Alejandro D
authors.initials: AD
authors.lastname: Roth
authors.affiliation: Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile, rdelgado@uchile.cl.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Delgado
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000032:analysis / Q000737:chemistry*; D004331:Drosophila melanogaster / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis*; D055537:Light Signal Transduction / Q000502:physiology; D008871:Microvilli / Q000737:chemistry*; D017956:Photoreceptor Cells, Invertebrate / Q000737:chemistry*; D021381:Protein Transport / Q000502:physiology; D050051:Transient Receptor Potential Channels / Q000032:analysis / Q000737:chemistry*
chemical_list: D029721:Drosophila Proteins; D005227:Fatty Acids; D050051:Transient Receptor Potential Channels; C074192:trpl protein, Drosophila