title: The Drosophila TRPL ion channel shares a Rab-dependent translocation pathway with rhodopsin.
abstract: The Drosophila visual transduction cascade is embedded in the rhabdomeres of photoreceptor cells and culminates in the opening of the two ion channels, TRP and TRPL. TRPL translocates from the rhabdomeres to the cell body upon illumination and vice versa when flies are kept in the dark. Here, we studied the mechanisms underlying the light-dependent internalization of TRPL. Co-localization of TRPL and rhodopsin in endocytic particles revealed that TRPL is internalized by a vesicular transport pathway that is also utilized, at least partially, for rhodopsin endocytosis. TRPL internalization is attenuated under light conditions that result in a high rate of rhodopsin internalization and is highest in orange light that result in very little rhodopsin internalization. In line with a canonical vesicular transport pathway, we found that rab proteins, Rab5 and RabX4, are required for the internalization of TRPL into the cell body. Our results provide insight into stimulus-dependent internalization of a prominent member of the TRP superfamily.
authors.affiliation: Department of Biosensorics, Institute of Physiology, University of Hohenheim, 70599 Stuttgart, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Oberegelsbacher
authors.forename: Carina
authors.initials: C
authors.lastname: Schneidler
authors.forename: Olaf
authors.initials: O
authors.lastname: Voolstra
authors.forename: Alexander
authors.initials: A
authors.lastname: Cerny
authors.forename: Armin
authors.initials: A
authors.lastname: Huber
mesh_terms: D000818:Animals; D019390:Arrestins / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D007150:Immunohistochemistry; D017956:Photoreceptor Cells, Invertebrate; D021381:Protein Transport / Q000502:physiology; D012243:Rhodopsin / Q000378:metabolism*; D015398:Signal Transduction; D050051:Transient Receptor Potential Channels / Q000378:metabolism*; D014785:Vision, Ocular; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D019390:Arrestins; D029721:Drosophila Proteins; D050051:Transient Receptor Potential Channels; C074192:trpl protein, Drosophila; D012243:Rhodopsin; C567986:RabX4 protein, Drosophila; D020691:rab GTP-Binding Proteins; D020696:rab5 GTP-Binding Proteins