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The mosquito Aedes aegypti (L.) leucokinin receptor is a multiligand receptor for the three Aedes kinins

Authors


Professor Patricia V. Pietrantonio, Department of Entomology, Texas A&M University, 2475 TAMU, College Station, TX 77843–2475, USA. Tel.: +1 979 845 9728; fax: +1 979 845 6305; e-mail: p-pietrantonio@tamu.edu

Abstract

A cDNA cloned from Aedes aegypti (L.) (Aedae) female Malpighian tubule (AY596453) encodes a 584 amino acid residue protein (65.2 kDa) predicted as a G protein-coupled receptor and orthologue of the drosokinin receptor from Drosophila melanogaster and highly similar to the tick Boophilus microplus myokinin receptor (AF228521). Based on the similarity to this Aedes sequence, we also propose a correction for the Anopheles gambiae protein sequence EAA05450. When expressed in CHO-K1 cells, the Aedes receptor behaved as a multiligand receptor and functionally responded to concentrations ≥ 1 nm of Aedae kinins 1–3, respectively, as determined by a calcium bioluminescence plate assay and single cell intracellular calcium measurements by confocal fluorescence cytometry. Estimates of EC50 values by the plate assay were 16.04 nm for Aedae-K-3, 26.6 nm for Aedae-K-2 and 48.8 nm for Aedae-K-1 and were statistically significantly different. These results suggest that the observed differences in physiological responses to the three Aedes kinins in the Aedes isolated Malpighian tubule reported elsewhere could now be explained by differences in intracellular signalling events triggered by the different peptides on the same receptor and not necessarily due to the existence of various receptors for the three Aedes kinins.

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