title: Adipokinetic hormone receptor gene identification and its role in triacylglycerol metabolism in the blood-sucking insect Rhodnius prolixus.
abstract: Adipokinetic hormone (AKH) has been associated with the control of energy metabolism in a large number of arthropod species due to its role on the stimulation of lipid, carbohydrate and amino acid mobilization/release. In the insect Rhodnius prolixus, a vector of Chagas' disease, triacylglycerol (TAG) stores must be mobilized to sustain the metabolic requirements during moments of exercise or starvation. Besides the recent identification of the R. prolixus AKH peptide, other components required for the AKH signaling cascade and its mode of action remain uncharacterized in this insect. In the present study, we identified and investigated the expression profile of the gene encoding the AKH receptor of R. prolixus (RhoprAkhr). This gene is highly conserved in comparison to other sequences already described and its transcript is abundant in the fat body and the flight muscle of the kissing bug. Moreover, RhoprAkhr expression is induced in the fat body at moments of increased TAG mobilization; the knockdown of this gene resulted in TAG accumulation both in fat body and flight muscle after starvation. The inhibition of Rhopr-AKHR transcription as well as the treatment of insects with the peptide Rhopr-AKH in its synthetic form altered the transcript levels of two genes involved in lipid metabolism, the acyl-CoA-binding protein-1 (RhoprAcbp1) and the mitochondrial glycerol-3-phosphate acyltransferase-1 (RhoprGpat1). These results indicate that the AKH receptor is regulated at transcriptional level and is required for TAG mobilization under starvation. In addition to the classical view of AKH as a direct regulator of enzymatic activity, we propose here that AKH signaling may account for the regulation of nutrient metabolism by affecting the expression profile of target genes.
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Alves-Bezerra
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Iron F
authors.initials: IF
authors.lastname: De Paula
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Medina
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Gleidson
authors.initials: G
authors.lastname: Silva-Oliveira
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Jonas S
authors.initials: JS
authors.lastname: Medeiros
authors.affiliation: Department of Biological Sciences, University of Cape Town, John Day Building, Rondebosch ZA-7701, South Africa.
authors.forename: Gerd
authors.initials: G
authors.lastname: Gäde
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: katia@bioqmed.ufrj.br.
authors.forename: Katia C
authors.initials: KC
authors.lastname: Gondim
mesh_terms: D000818:Animals; D005216:Fat Body / Q000378:metabolism; D005426:Flight, Animal; D005508:Food Deprivation; D005786:Gene Expression Regulation; D007301:Insect Hormones / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D012239:Rhodnius / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D007301:Insect Hormones; D009842:Oligopeptides; D011956:Receptors, Cell Surface; D014280:Triglycerides; C044833:adipokinetic hormone; D011761:Pyrrolidonecarboxylic Acid
keywords: Acyl-CoA-binding protein (ACBP); Adipokinetic hormone (AKH); Adipokinetic hormone receptor (AKHR); Glycerol-3-phosphate acyltransferase (GPAT); Lipid mobilization