Receptor guanylyl cyclases in Inka cells targeted by eclosion hormone.
A signature of eclosion hormone (EH) action in insect ecdysis is elevation of cGMP in Inka cells, leading to massive release of ecdysis triggering hormone (ETH) and ecdysis initiation. Although this aspect of EH-induced signal transduction is well known, the receptor mediating this process has not been identified. Here, we describe a receptor guanylyl cyclase BdmGC-1 and its isoform BdmGC-1B in the Oriental fruit fly Bactrocera dorsalis that are activated by EH. The B form exhibits the conserved domains and putative N-glycosylation sites found in BdmGC-1, but possesses an additional 46-amino acid insertion in the extracellular domain and lacks the C-terminal tail of BdmGC-1. Combined immunolabeling and in situ hybridization reveal that BdmGC-1 is expressed in Inka cells. Heterologous expression of BdmGC-1 in HEK cells leads to robust increases in cGMP following exposure to low picomolar concentrations of EH. The B-isoform responds only to higher EH concentrations, suggesting different physiological roles of these cyclases. We propose that BdmGC-1 and BdmGC-1B are high- and low-affinity EH receptors, respectively.
Chang
Jer-Cherng
JC
Department of Entomology, National Chung Hsing University, Taichung, Taiwan 40227, Republic of China.
Yang
Ruey-Bing
RB
Adams
Michael E
ME
Lu
Kuang-Hui
KH
D000818:Animals; D002460:Cell Line; D006152:Cyclic GMP / Q000378:metabolism; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D007301:Insect Hormones / Q000494:pharmacology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D050705:Receptors, Guanylate Cyclase-Coupled / Q000378:metabolism*; D040681:Structural Homology, Protein; D033621:Tephritidae / Q000187:drug effects / Q000378:metabolism*; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D007301:Insect Hormones; D020033:Protein Isoforms; C042645:eclosion hormone; D050705:Receptors, Guanylate Cyclase-Coupled; D006152:Cyclic GMP