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17.07.2015 16:22 Von: Sarah Danes

Large-scale deorphanization of G-protein coupled receptors

Philipp Bauknecht first author in Cell Reports


Second year IMPRS student Philipp Bauknecht is carrying out his doctoral research in the laboratory of Gáspár Jékely, Max Planck Research Group Leader at the Max Planck Institute for Developmental Biology. Philipp’s work focuses on neuropeptide signaling, using the marine annelid worm Platynereis dumerilii as a model system. Neuronal signaling in Platynereis features extensive use of neuropeptide ligands and G-protein coupled receptors (GPCRs). Philipp is using large-scale deorphanization to identify individual neuropeptide receptors, characterize their expression patterns and find out how they modify neuronal action.

 

For the deorphanization, Philipp developed a combinatorial screening strategy in which 87 GPCRs were tested for binding against 126 synthetic neuropeptides (10,962 combinations). “We had to come up with a clever strategy to get the work done in about a year rather than five years or more”, says Philipp. This involved testing complex neuropeptide mixtures on each GPCR, using fluorescence to indicate a match between the GPCR and any of the ligands. Philipp then tested successive subsets of the neuropeptide mixtures to ultimately find the correct ligands for the GPCRs. To validate the results, dose-response curves were recorded for each of the identified receptor-ligand pairs.

 

In their article in Cell Reports1, Philipp and Gáspár report identification of the peptide ligand of 19 Platynereis receptors. In addition, phylogenetic analysis of Platynereis and other metazoan neuropeptide GPCRs provides insights into the evolution of peptidergic signaling in bilaterians. Their work was further highlighted with a front cover displaying a spectacular scanning electron microscopy (SEM) image of a four-segmented juvenile Platynereis dumerilii. To read more about the article, visit the official press release.

 

Philipp still wants to visualize the expression patterns of the GPCRs by in-situ hybridization and reporter gene expression. “In the long run, I would like to study how the GPCRs modulate neuronal action with the help of calcium indicators like GCaMP or CaMPARI. This will allow us to learn more about the organization of simple nervous systems.”

 

1Bauknecht P & Jekely G (2015). Large-Scale Combinatorial Deorphanization of Platynereis Neuropeptide GPCRs. Cell Rep 12, 684-93.