Dataset Information

Identification of multiple functional receptors for tyramine on an insect secretory epithelium.

ABSTRACT: The biogenic amine tyramine (TA) regulates many aspects of invertebrate physiology and development. Although three TA receptor subtypes have been identified (TAR1-3), specific receptors have not been linked to physiological responses in native tissue. In the Malpighian (renal) tubule of Drosophila melanogaster, TA activates a transepithelial chloride conductance, resulting in diuresis and depolarization of the transepithelial potential. In the current work, mutation or RNAi-mediated knockdown in the stellate cells of the tubule of TAR2 (tyrR, CG7431) resulted in a dramatic reduction, but not elimination, of the TA-mediated depolarization. Mutation or knockdown of TAR3 (tyrRII, CG16766) had no effect. However, deletion of both genes, or knockdown of TAR3 on a TAR2 mutant background, eliminated the TA responses. Thus while TAR2 is responsible for the majority of the TA sensitivity of the tubule, TAR3 also contributes to the response. Knockdown or mutation of TAR2 also eliminated the response of tubules to the related amine octopamine (OA), indicating that OA can activate TAR2. This finding contrasts to reports that heterologously expressed TAR2 is highly selective for TA over OA. This is the first report of TA receptor function in a native tissue and indicates unexpected complexity in the physiology of the Malpighian tubule.

SUBMITTER: Zhang H

PROVIDER: S-EPMC5427925 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identification of multiple functional receptors for tyramine on an insect secretory epithelium.

Zhang Haiying H Blumenthal Edward M EM

Scientific reports 20170313 1

The biogenic amine tyramine (TA) regulates many aspects of invertebrate physiology and development. Although three TA receptor subtypes have been identified (TAR1-3), specific receptors have not been linked to physiological responses in native tissue. In the Malpighian (renal) tubule of Drosophila melanogaster, TA activates a transepithelial chloride conductance, resulting in diuresis and depolarization of the transepithelial potential. In the current work, mutation or RNAi-mediated knockdown in ...[more]

PMID: 28279025

Similar Datasets

Project description:BackgroundEicosanoids are a group of the oxygenated C20 polyunsaturated fatty acids and play crucial roles in mediating various insect physiological processes. Catalytic activity of phospholipase A2 (PLA2) provides an initial substrate, arachidonic acid (AA), for subsequent eicosanoid biosynthesis.ResultsThis study identified four different secretory PLA2 (As-PLA2A-As-PLA2D) genes encoded in the Asian onion moth, Acrolepiopsis sapporensis. A phylogenetic analysis indicated that As-PLA2A and As-PLA2D are clustered with Group III PLA2s while As-PLA2B and As-PLA2C are clustered with Group XII and Group X PLA2s, respectively. Expression levels of these PLA2 genes increased along with larval development, especially in the fat body. A bacterial immune challenge upregulated the basal expression levels of the four PLA2 genes, which resulted in significant increases of the PLA2 enzyme activity. The enzyme activity was susceptible to a calcium chelator or reducing agent, suggesting Ca2+ dependency and disulfide linkage required for the catalytic activities of the secretory type of PLA2s. In addition, the PLA2 activity was also susceptible to bromophenacyl bromide (BPB), a specific inhibitor to sPLA2, but not to intracellular PLA2 inhibitors. An addition of BPB to the immune challenge significantly prevented hemocyte-spreading behavior of A. sapporensis. BPB treatment also suppressed a cellular immune response measured by hemocyte nodule formation. However, the immunosuppression was significantly rescued by the AA addition. To determine the PLA2(s) responsible for the immunity, individual RNA interference (RNAi) treatments specific to each of the four PLA2s were performed. Injection of gene-specific double-stranded RNAs caused significant reductions in the transcript level in all four PLA2s. In all four PLA2s, the RNAi treatments prevented the cellular immune response even after the immune challenge.ConclusionThis study reports four secretory PLA2s encoded in A. sapporensis and their function in mediating cellular immunity.

Dataset Information

Identification of multiple functional receptors for tyramine on an insect secretory epithelium.

Publications

Identification of multiple functional receptors for tyramine on an insect secretory epithelium.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets