Molecular cloning and functional expression of a Drosophila receptor for the neuropeptides capa-1 and -2

The Drosophila Genome Project website contains an annotated gene (CG14575) for a G protein-coupled receptor. We cloned this receptor and found that the cloned cDNA did not correspond to the annotated gene; it partly contained different exons and additional exons located at the 5(')-end of the annotated gene. We expressed the coding part of the cloned cDNA in Chinese hamster ovary cells and found that the receptor was activated by two neuropeptides, capa-1 and -2, encoded by the Drosophila capability gene. Database searches led to the identification of a similar receptor in the genome from the malaria mosquito Anopheles gambiae (58% amino acid residue identities; 76% conserved residues; and 5 introns at identical positions within the two insect genes). Because capa-1 and -2 and related insect neuropeptides stimulate fluid secretion in insect Malpighian (renal) tubules, the identification of this first insect capa receptor will advance our knowledge on insect renal function.