|Guerrero, Felicito - Felix|
|VAN POYER, WENDY|
|DE LOOF, ARNOLD|
|VANDEN BROECK, JOZEF|
Submitted to: Journal of Neurochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2000
Publication Date: N/A
Interpretive Summary: Tachykinins are peptides which belong to a large family of multifunctional brain/gut peptides in mammals. They play an important role in the central nervous system, both in processing of sensory information and the control of motor activities. In insects, tachykinin-like peptides have been shown to be important in digestive processes and muscle contractions of the oviduct. STKR is a gene product which has been cloned from the stable fly Stomoxys calcitrans, and appears to be a receptor for tachykinin-like peptides in that species. STKR has been cloned into an insect cell line and the gene product expressed. Cells which expressed the STKR gene product were assayed for response to various insect tachykinins and other physiologically active biochemicals.
Technical Abstract: STKR is an insect G protein-coupled receptor, cloned from the stable fly Stomoxys calcitrans. It displays sequence similarity to vertebrate tachykinin [or neurokinin (NK)] receptors. Functional expression of the cloned STKR cDNA was obtained in cultured Drosophila melanogaster Schneider 2 (S2) cells. Insect tachykinin-like peptides or "insectatachykinins," such as Locusta tachykinin (Lom-TK) III, produced dose-dependent calcium responses in stably transfected S2-STK cells. Vertebrate tachykinins (or neurokinins) did not evoke any effect at concentrations up to 10-5 M, but an antagonist of mammalian neurokinin receptors, spantide II, inhibited the Lom-TK III-induced calcium response. Further analysis showed that the agonist-induced intracellular release of calcium ions was not affected by the pretreatment of the cells with pertussis toxin. The calcium rise was blocked by the phospholipase C inhibitor U73122. In addition, Lom-TK III was shown to have a stimulatory effect on the accumulation of both inosito 1,4,5-trisphosphate and cyclic AMP. These are the same second messengers that are induced in mammalian neurokinin-dependent signaling processes.