title: An animal homolog of plant Mep/Amt transporters promotes ammonia excretion by the anal papillae of the disease vector mosquito Aedes aegypti.
abstract: The transcripts of three putative ammonia (NH3/NH4 (+)) transporters, Rhesus-like glycoproteins AeRh50-1, AeRh50-2 and Amt/Mep-like AeAmt1 were detected in the anal papillae of larval Aedes aegypti Quantitative PCR studies revealed 12-fold higher transcript levels of AeAmt1 in anal papillae relative to AeRh50-1, and levels of AeRh50-2 were even lower. Immunoblotting revealed AeAmt1 in anal papillae as a pre-protein with putative monomeric and trimeric forms. AeAmt1 was immunolocalized to the basal side of the anal papillae epithelium where it co-localized with Na(+)/K(+)-ATPase. Ammonium concentration gradients were measured adjacent to anal papillae using the scanning ion-selective electrode technique (SIET) and used to calculate ammonia efflux by the anal papillae. dsRNA-mediated reductions in AeAmt1 decreased ammonia efflux at larval anal papillae and significantly increased ammonia levels in hemolymph, indicating a principal role for AeAmt1 in ammonia excretion. Pharmacological characterization of ammonia transport mechanisms in the anal papillae suggests that, in addition to AeAmt1, the ionomotive pumps V-type H(+)-ATPase and Na(+)/K(+)-ATPase as well as NHE3 are involved in ammonia excretion at the anal papillae.
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Helen
authors.initials: H
authors.lastname: Chasiotis
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Adrian
authors.initials: A
authors.lastname: Ionescu
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Lidiya
authors.initials: L
authors.lastname: Misyura
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Phuong
authors.initials: P
authors.lastname: Bui
authors.affiliation: Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Fazio
authors.affiliation: Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Patrick
authors.affiliation: Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba, Canada R3T 2N2.
authors.forename: Dirk
authors.initials: D
authors.lastname: Weihrauch
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3 adonini@yorku.ca.
authors.forename: Andrew
authors.initials: A
authors.lastname: Donini
mesh_terms: D000330:Aedes / Q000235:genetics / Q000378:metabolism*; D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D027682:Cation Transport Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004199:Disease Vectors; D004848:Epithelium / Q000378:metabolism; D015870:Gene Expression; D019476:Insect Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
chemical_list: D027682:Cation Transport Proteins; D019476:Insect Proteins; D010940:Plant Proteins; C088952:ammonium transporters, plant; D000641:Ammonia
keywords: Ammonium transporter; Carbonic anhydrase; NHE3; Na+/K+-ATPase; Rhesus glycoprotein; V-type H+-ATPase