Probing rhodopsin-transducin interaction using Drosophila Rh1-bovine rhodopsin chimeras.
Invertebrate and vertebrate rhodopsins share a low degree of homology and are coupled to G-proteins from different families. Here we explore the utility of fly-expressed chimeras between Drosophila rhodopsin Rh1 and bovine rhodopsin (Rho) to probe the interactions between the invertebrate and vertebrate visual pigments and their cognate G-proteins. Chimeric Rh1 pigments carrying individual substitutions of the cytoplasmic loops C2 and C3 and the C-terminus with the corresponding regions of Rho retained the ability to stimulate phototranduction in Drosophila, but failed to activate transducin. Surprisingly, chimeric Rho containing the Rh1 C-terminus was fully capable of transducin activation, indicating that the C-terminal domain of vertebrate rhodopsins is not essential for the functional coupling to transducin.
Natochin
Michael
M
Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
Barren
Brandy
B
Ahmad
Syed Tariq
ST
O'Tousa
Joseph E
JE
Artemyev
Nikolai O
NO
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D002417:Cattle; D004330:Drosophila; D004596:Electroretinography; D019204:GTP-Binding Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D012243:Rhodopsin / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013045:Species Specificity; D013329:Structure-Activity Relationship; D020079:Terminal Repeat Sequences; D015293:Transducin / Q000378:metabolism*; D014785:Vision, Ocular / Q000502:physiology
D012243:Rhodopsin; D019204:GTP-Binding Proteins; D015293:Transducin