Live Staining of Drosophila Embryos with RPTP Fusion Proteins to Detect and Characterize Expression of Cell-Surface RPTP Ligands

The activity and/or localization of receptor tyrosine kinases and phosphatases are controlled by binding to cell-surface or secreted ligands. Identification of ligands for receptor tyrosine phosphatases (RPTPs) is essential for understanding their in vivo functions during development and disease. Here we describe a novel in vivo method to identify ligands and binding partners for RPTPs by staining live-dissected Drosophila embryos. Live dissected embryos are incubated with RPTP fusion proteins to detect ligand binding in embryos. This method can be streamlined to perform large-scale screens for ligands as well as to search for embryonic phenotypes.