Functional co-assembly among subunits of cyclic-nucleotide-activated, nonselective cation channels, and across species from nematode to human.
Cyclic-nucleotide-activated, nonselective cation channels have a central role in sensory transduction. They are most likely tetramers, composed of two subunits (alpha and beta or 1 and 2), with the former, but not the latter, being able to form homomeric cyclic-nucleotide-activated channels. Identified members of this channel family now include, in vertebrates, the rod and cone channels mediating visual transduction and the channel mediating olfactory transduction, each apparently with distinct alpha- and beta-subunits. Homologous channels have also been identified in Drosophila melanogaster and Caenorhabditis elegans. By co-expressing any combination of two alpha-subunits, or alpha- and beta-subunits, of this channel family in HEK 293 cells, we have found that they can all co-assemble functionally with each other, including those from fly and nematode. This finding suggests that the subunit members so far identified form a remarkably homogeneous and conserved group, functionally and evolutionarily, with no subfamilies yet identified. The ability to cross-assemble allows these subunits to potentially generate a diversity of heteromeric channels, each with properties specifically suited to a particular cellular function.
Finn
J T
JT
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Krautwurst
D
D
Schroeder
J E
JE
Chen
T Y
TY
Reed
R R
RR
Yau
K W
KW
D000818:Animals; D017173:Caenorhabditis elegans; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism* / Q000494:pharmacology; D004331:Drosophila melanogaster; D006801:Humans; D007473:Ion Channels / Q000096:biosynthesis / Q000737:chemistry* / Q000502:physiology*; D007668:Kidney; D007700:Kinetics; D046911:Macromolecular Substances; D009348:Nematoda; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D013045:Species Specificity; D014162:Transfection; D014714:Vertebrates; D014785:Vision, Ocular / Q000502:physiology*
D007473:Ion Channels; D046911:Macromolecular Substances; D011994:Recombinant Proteins; D000242:Cyclic AMP; D006152:Cyclic GMP