Author:

Abstract:

Neuropeptides form a versatile class of messenger molecules that regulate many, if not all, biological processes in insects. The vast majority of these peptide or protein hormones act by activating G protein-coupled receptors (GPCRs), the most diverse category of signal transducing membrane-associated proteins. Here, we will present an overview of some novel findings illustrating the importance of GPCR signaling in regulating behavioral and developmental processes in the fruit fly, Drosophila melanogaster. 1) Recently we characterized NKD (neurokinin receptor from Drosophila, CG6515), as a receptor for DTK-6 (Drosophila tachykinin-related peptide 6). Most interestingly, this peptide possesses an Ala-substitution in an otherwise conserved C-terminal core motif. Together with DTKR (Drosophila tachykinin receptor, CG7887), a second fly GPCR that shows sequence similarity to mammalian tachykinin receptors, NKD is widely distributed in the central nervous system of larval and adult flies. In fact, NKD and DTKR appear to show mutually exclusive expression patterns that correspond well with the endogenous presence of DTKs. 2) Leucine-rich repeat containing GPCRs (or LGRs) constitute a unique receptor subgroup with well-conserved members in both vertebrates and invertebrates. We have analyzed the expression profile of LGR encoding genes during fly development. In addition, RNA interference (RNAi) experiments and mutation studies are performed in the fruit fly to investigate the in vivo significance of these signaling systems.