title: Mutation of light-dependent phosphorylation sites of the Drosophila transient receptor potential-like (TRPL) ion channel affects its subcellular localization and stability.
abstract: The Drosophila phototransduction cascade terminates in the opening of the ion channel transient receptor potential (TRP) and TRP-like (TRPL). Contrary to TRP, TRPL undergoes light-dependent subcellular trafficking between rhabdomeric photoreceptor membranes and an intracellular storage compartment, resulting in long term light adaptation. Here, we identified in vivo phosphorylation sites of TRPL that affect TRPL stability and localization. Quantitative mass spectrometry revealed a light-dependent change in the TRPL phosphorylation pattern. Mutation of eight C-terminal phosphorylation sites neither affected multimerization of the channels nor the electrophysiological response of flies expressing the mutated channels. However, these mutations resulted in mislocalization and enhanced degradation of TRPL after prolonged dark-adaptation. Mutation of subsets of the eight C-terminal phosphorylation sites also led to a reduction of TRPL content and partial mislocalization in the dark. This suggests that a light-dependent switch in the phosphorylation pattern of the TRPL channel mediates stable expression of TRPL in the rhabdomeres upon prolonged dark-adaptation.
authors.affiliation: Department of Biosensorics, Institute of Physiology, University of Hohenheim, 70599 Stuttgart, Germany.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Cerny
authors.forename: Tina
authors.initials: T
authors.lastname: Oberacker
authors.forename: Jens
authors.initials: J
authors.lastname: Pfannstiel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Weigold
authors.forename: Carina
authors.initials: C
authors.lastname: Will
authors.forename: Armin
authors.initials: A
authors.lastname: Huber
mesh_terms: D000818:Animals; D003623:Dark Adaptation / Q000502:physiology*; D029721:Drosophila Proteins / Q000096:biosynthesis* / Q000235:genetics; D004331:Drosophila melanogaster; D008027:Light; D009154:Mutation; D010766:Phosphorylation / Q000502:physiology; D055550:Protein Stability; D021381:Protein Transport / Q000502:physiology; D050051:Transient Receptor Potential Channels / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D029721:Drosophila Proteins; D050051:Transient Receptor Potential Channels; C074192:trpl protein, Drosophila
keywords: Drosophila; Protein Phosphorylation; TRP Channels; Trafficking; Vision