title: Ligand binding-dependent functions of the lipocalin NLaz: an in vivo study in Drosophila.
abstract: Lipocalins are small extracellular proteins mostly described as lipid carriers. The Drosophila lipocalin NLaz (neural Lazarillo) modulates the IIS pathway and regulates longevity, stress resistance, and behavior. Here, we test whether a native hydrophobic pocket structure is required for NLaz to perform its functions. We use a point mutation altering the binding pocket (NLaz(L130R)) and control mutations outside NLaz binding pocket. Tryptophan fluorescence titration reveals that NLaz(L130R) loses its ability to bind ergosterol and the pheromone 7(z)-tricosene but retains retinoic acid binding. Using site-directed transgenesis in Drosophila, we test the functionality of the ligand binding-altered lipocalin at the organism level. NLaz-dependent life span reduction, oxidative stress and starvation sensitivity, aging markers accumulation, and deficient courtship are rescued by overexpression of NLaz(WT), but not of NLaz(L130R). Transcriptional responses to aging and oxidative stress show a large set of age-responsive genes dependent on the integrity of NLaz binding pocket. Inhibition of IIS activity and modulation of oxidative stress and infection-responsive genes are binding pocket-dependent processes. Control of energy metabolites on starvation appears to be, however, insensitive to the modification of the NLaz binding pocket.
authors.affiliation: 2Instituto de Biología y Genética Molecular, c/Sanz y Forés 3, Universidad de Valladolid-CSIC, 47003 Valladolid, Spain. lazarill@ibgm.uva.es.
authors.forename: Mario
authors.initials: M
authors.lastname: Ruiz
authors.forename: Maria D
authors.initials: MD
authors.lastname: Ganfornina
authors.forename: Colin
authors.initials: C
authors.lastname: Correnti
authors.forename: Roland K
authors.initials: RK
authors.lastname: Strong
authors.forename: Diego
authors.initials: D
authors.lastname: Sanchez
mesh_terms: D000375:Aging / Q000187:drug effects / Q000235:genetics; D000475:Alkenes / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D004875:Ergosterol / Q000737:chemistry / Q000378:metabolism; D006540:Herbicides / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008024:Ligands; D054834:Lipocalins / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016877:Oxidants / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D017354:Point Mutation; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics; D014212:Tretinoin / Q000737:chemistry / Q000378:metabolism
chemical_list: D000475:Alkenes; D002352:Carrier Proteins; D029721:Drosophila Proteins; D006540:Herbicides; D008024:Ligands; D054834:Lipocalins; D008562:Membrane Glycoproteins; C490458:NLaz protein, Drosophila; D016877:Oxidants; C050395:7-tricosene; D014212:Tretinoin; D006861:Hydrogen Peroxide; D010269:Paraquat; D004875:Ergosterol
keywords: aging; lipid-binding proteins; metabolism regulation; oxidative stress; pheromonal signaling