Regulation ofDrosophilaTRPL Channels by Immunophilin FKBP59

摘要: Transient receptor potential and transient potential-like (TRPL) are Ca2+-permeable cation channels found inDrosophila photoreceptor cells associated with large multimeric signaling complexes held together by the scaffolding protein, INAD. To identify novel proteins involved in channel regulation, Drosophila INAD was used as bait a yeast two-hybrid screen of head cDNA library. Sequence analysis one identified clone showed it to be identical homolog human FK506-binding FKBP52 (previously known FKBP59). determine function dFKBP59, TRPL dFKBP59 were co-expressed Sf9 cells. Expression produced an inhibition Ca2+influx via fura-2 assays. Likewise, purified recombinant graded single activity excised inside-out patches when added cytoplasmic membrane surface. Immunoprecipitations from cell lysates using tagged that these directly interact each other Addition FK506 prior immunoprecipitation resulted temperature-dependent dissociation TRPL. fromDrosophila S2 fly demonstrated but not dFKBP12, interacts vivo. immunoprecipitates lysates. Immunocytochemical evaluation thin sections heads revealed specific FKBP immunoreactivity eye. Site-directed mutagenesis mutations P702Q or P709Q highly conserved sequence701LPPPFNVLP709 eliminated interaction dFKBP59. These results provide strong support for hypothesis immunophilin is part TRPL-INAD complex plays important role modulation leucyl-prolyl dipeptides located near mouth channel.