Functional differences between two CRF-related diuretic hormone receptors in Drosophila

Abstract

SUMMARYIn Drosophila, two related G-protein-coupled receptors are members of the corticotropin releasing factor (CRF) receptor subfamily. We have previously reported that one of these receptors, encoded by CG8422 is a functional receptor for a diuretic hormone, DH 44 . Here, we report that the other CRF receptor subfamily member, encoded by CG12370, is also a receptor for the DH 44 neuropeptide. The lines of evidence to support this identification include increases in cAMP levels due to CG12370 receptor activation and the recruitment of β-arrestin-GFP to the plasma membrane in response to DH 44 application. We compared these features of the receptors DH44-R2 (encoded by CG12370) and DH44-R1 (encoded by CG8422) and found fundamental differences in signaling, association with the arrestins, and peptide sensitivity. We found that the sensitivity of DH44-R2 to the DH 44 peptide is lower than that of DH44-R1, specifically an estimated EC 50 of 7.98E-07 mol l -1 for DH 44 by DH44-R2 to an EC 50 of 5.12E-09 mol l -1 by DH44-R1 and found that previous reports on the sensitivity of the tubule to DH 44 is in agreement with our measurements of DH44-R2 sensitivity. We employed a specific RNAi construct to selectively knock-down DH44-R2 expression and this led to heightened sensitivity to osmotic challenges. The functional characterization of this diuretic hormone receptor in Drosophila demonstrates a high degree of conservation of CRF-like signaling.

In silico cloning of genes encoding neuropeptides, neurohormones and their putative G-protein coupled receptors in a spider mite

“…Two GPCRs (tetur01g00270 and tetur01g03970) of the B-family are very similar to (best BLAST e-values 1e-114 and 2e-99) and cluster convincingly with the insect receptors for DH44 (Fig. 7), which have been functionally identified in several species (Reagen, 1994;Johnson et al, 2004;Hector et al, 2009). The Drosophila DH31 receptor has also been identified (Johnson et al, 2005) and its insect orthologs cluster with a Tetranychus GPCR (tetur15g02300) which is very similar to those proteins (best BLAST e-value 8e-114) and thus is likely the spider mite DH31 receptor (Fig.…”

Cell signalling mechanisms for insect stress tolerance

“…DH-44 is a ligand for two receptors, DH-44 R1 and R2 (Hector et al, 2009;Johnson et al, 2005). DH-44 R2 is encoded by CG12370 (Hector et al, 2009), and is expressed in epithelial tissue but most highly in tubules in the adult fly (Chintapalli et al, 2007;Robinson et al, 2013). cAMP signalling, induced by exogenous cAMP (Riegel et al, 1998) as well as DH-44, increases fluid secretion rates by acting on the tubule principal cell (Cabrero et al, 2002;Dow et al, 1994b).…”

Separate roles of PKA and EPAC in renal function unraveled by the optogenetic control of cAMP levels in vivo

“…We used DH 44 , a diuretic neuropeptide that augments fluid secretion via cAMP signaling in the principal cells (Johnson et al, 2005;Hector et al, 2009) to elicit a physiological response. The stimulatory effects of DH 44 were reduced in null epac mutants (Fig.…”