The PDZ assembled "transducisome" of microvillar photoreceptors: the TRP/TRPL problem.
Two types of ion channels, TRP and TRPL, are activated upon light-absorption in rhabdomeral photoreceptor membranes of fly compound eyes. Whereas TRP is associated with other signaling proteins into a multiprotein complex (transducisome), the molecular organization of TRPL is discussed controversely. We analysed the TRPL content of blowfly rhabdomeral membranes and investigated by co-immunoprecipitation studies whether or not TRPL is part of the transducisome. Compared to TRP there are at least ten times less TRPL molecules present in the rhabdomeral membrane. A small fraction of the total TRPL present co-immunoprecipitates with other proteins of the transducisome and vice versa. Our data suggest that a significant fraction of TRPL is not incorporated into the transducisome. This fraction may either form independent ion channels or bind to the transducisome transiently.
Paulsen
R
R
Department of Cell- and Neurobiology, University of Karlsruhe, Germany.
Bähner
M
M
Huber
A
A
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D004175:Diptera / Q000378:metabolism*; D029721:Drosophila Proteins; D005136:Eye Proteins / Q000378:metabolism; D019476:Insect Proteins / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism*; D050051:Transient Receptor Potential Channels; D014785:Vision, Ocular / Q000502:physiology*
D015220:Calcium Channels; D002148:Calmodulin-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; D050051:Transient Receptor Potential Channels; C091568:inaD protein, Drosophila; C063169:trp protein, Drosophila; C074192:trpl protein, Drosophila