title: Functional differences between two CRF-related diuretic hormone receptors in Drosophila.
abstract: In 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 beta-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 moll(-1) for DH(44) by DH44-R2 to an EC(50) of 5.12E-09 moll(-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.
authors.affiliation: Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Hector
authors.forename: Colin A
authors.initials: CA
authors.lastname: Bretz
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Erik C
authors.initials: EC
authors.lastname: Johnson
mesh_terms: D000818:Animals; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000378:metabolism*; D006801:Humans; D034622:RNA Interference; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D011956:Receptors, Cell Surface; C545615:diuretic hormone 44 receptor 1, Drosophila; C545616:diuretic hormone 44 receptor 2, Drosophila