Two nitridergic peptides are encoded by the genecapabilityinDrosophila melanogaster

Abstract

A Drosophila gene ( capability, capa) at 99D on chromosome 3R potentially encodes three neuropeptides: GANMGLYAFPRV-amide (capa-1), ASGLVAFPRV-amide (capa-2), and TGPSASSGLWGPRL-amide (capa-3). Capa-1 and capa-2 are related to the lepidopteran hormone cardioacceleratory peptide 2b, while capa-3 is a novel member of the pheromone biosynthesis-activating neuropeptide/diapause hormone/pyrokinin family. By immunocytochemistry, we identified four pairs of neuroendocrine cells likely to release the capa peptides into the hemolymph: one pair in the subesophageal ganglion and the other three in the abdominal neuromeres. In the Malpighian (renal) tubule, capa-1 and capa-2 increase fluid secretion rates, stimulate nitric oxide production, and elevate intracellular Ca2+ and cGMP in principal cells. Capa-stimulated fluid secretion, but not intracellular Ca2+ concentration rise, is inhibited by the guanylate cyclase inhibitor methylene blue. The actions of capa-1 and capa-2 are not synergistic, implying that both act on the same pathways in tubules. The capa gene is thus the first to be shown to encode neuropeptides that act on renal fluid production through nitric oxide.

Isolation, expression analysis, and functional characterization of the first antidiuretic hormone receptor in insects

“…The CAPA-related peptides in insects play key roles in regulating fluid secretion by MTs. In dipterans, these peptides are described as stimulating fluid secretion by the principal cells of MTs (6) by way of calcium signaling (18) and activation of nitric oxide synthase and soluble guanylate cyclase (6,19). Unlike this stimulatory effect in dipteran MTs, the CAPA-related peptide in R. prolixus, RhoprCAPA-α2(-β2), acts as an inhibitor of MT fluid secretion (9), counteracting the stimulatory effect of the diuretic hormone 5-HT, and thus is referred to as an "antidiuretic hormone."…”

Insect capa neuropeptides impact desiccation and cold tolerance

“…Among these are the capa peptides encoded by the capability (capa) neuropeptide gene (22). Capa peptides are distributed throughout the Insecta (23), including crop pests and disease vectors.…”

“…The D. melanogaster neuropeptide gene capa encodes two capa peptides (Drm-capa-1 and Drm-capa-2), homologs of the first identified capa peptide, Manduca sexta (Manse)-CAP2b (30), together with a third peptide, Drm-PK-1, which is a member of the pyrokinin peptide family (22). Both Drm-capa-1 and Drm-capa-2 perform a diuretic role in D. melanogaster Malpighian tubules (22), but the function of Drm-PK-1 is largely unknown. Drm-capa-1, Drm-capa-2, and Drm-PK-1 are produced from three pairs of ventral neuroendocrine cells in the abdominal neuromeres (Va neurons) ( Fig.…”

Nitric oxide directly regulates gene expression during Drosophila development: need some gas to drive into metamorphosis?: Figure 1.

“…In Malpighian (renal) tubules of Drosophila, two neuropeptides, capa-1 and capa-2, increase fluid secretion rates through the up-regulation of intracellular Ca 2+ concentration and subsequent NOS/cyclic GMP signaling (Kean et al 2002). Since Ca 2+ signaling is known to have an important role in the fly PG (Venkatesh and Hasan 1997) and some neuropeptides like the prothoracicotropic hormone (PTTH) are known to activate the Ca 2+ signaling pathway in the PG to regulate ecdysteroidogenesis (Gilbert et al 2002), it will be interesting to see whether the activities of these ecdysteroidogenic neuropeptides are mediated by NOS.…”

“…In insects, its diverse range of functions include regulation of renal fluid production, cell proliferation, synapse formation, and innate immunity (Kuzin et al 1996;Gibbs and Truman 1998;Kean et al 2002;Foley and O'Farrell 2003). In many of these cases, NO exerts its function through binding to the heme moiety of soluble guanylate cyclase to stimulate cyclic GMP synthesis.…”