Light-regulated interaction of Dmoesin with TRP and TRPL channels is required for maintenance of photoreceptors

• DOI: 10.1083/jcb.200503014
• Publication Date: 2005-10-10T19:42:46Z
• Authors: Irit Chorna-Ornan; Vered Tzarfaty; Galit Ankri-Eliahoo; Tamar Joel-Almagor; Nina E. Meyer; Armin Huber; François Payre; Baruch Minke
• Keywords: Models, Molecular; MESH: Protein Transport; MESH: Mutation; Light; MESH: Drosophila Proteins; 03 medical and health sciences; Cytosol; Transient Receptor Potential Channels; MESH: Cytosol; Animals; Drosophila Proteins; MESH: Animals; [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology; Phosphorylation; Research Articles; 0303 health sciences; MESH: Photoreceptors, Invertebrate; MESH: Phosphorylation; Cell Membrane; Membrane Proteins; MESH: Transient Receptor Potential Channels; MESH: Light; 3. Good health; Protein Transport; Mutation; Photoreceptor Cells, Invertebrate; MESH: Membrane Proteins; MESH: Models, Molecular; MESH: Cell Membrane

Recent studies in Drosophila melanogaster retina indicate that absorption of light causes the translocation of signaling molecules and actin from the photoreceptor's signaling membrane to the cytosol, but the underlying mechanisms are not fully understood. As ezrin-radixin-moesin (ERM) proteins are known to regulate actin–membrane interactions in a signal-dependent manner, we analyzed the role of Dmoesin, the unique D. melanogaster ERM, in response to light. We report that the illumination of dark-raised flies triggers the dissociation of Dmoesin from the light-sensitive transient receptor potential (TRP) and TRP-like channels, followed by the migration of Dmoesin from the membrane to the cytoplasm. Furthermore, we show that light-activated migration of Dmoesin results from the dephosphorylation of a conserved threonine in Dmoesin. The expression of a Dmoesin mutant form that impairs this phosphorylation inhibits Dmoesin movement and leads to light-induced retinal degeneration. Thus, our data strongly suggest that the light- and phosphorylation-dependent dynamic association of Dmoesin to membrane channels is involved in maintenance of the photoreceptor cells.