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Characterisation of a novel gene family of putative cyclic nucleotide‐ and calmodulin‐regulated ion channels in Arabidopsis thaliana
Author(s) -
Köhler Claudia,
Merkle Thomas,
Neuhaus Gunther
Publication year - 1999
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1999.00422.x
Subject(s) - arabidopsis , cyclic nucleotide binding domain , calmodulin , nucleotide , arabidopsis thaliana , biology , gene family , cyclic nucleotide , gene , biochemistry , mutant , cyclic nucleotide gated ion channel , homology (biology) , genetics , microbiology and biotechnology , gene expression , enzyme
Summary In plants, cyclic GMP is involved in signal transduction in response to light and gibberellic acid. For cyclic AMP, a potential role during the plant cell cycle was recently reported. However, cellular targets for cyclic nucleotides in plants are largely unknown. Here we report on the identification and characterisation of a new gene family in Arabidopsis, which share features with cyclic nucleotide‐gated channels from animals and inward‐rectifying K + channels from plants. The identified gene family comprises six members (Arabidopsis thaliana cyclic nucleotide‐gated channels, AtCNGC1–6) with significant homology among the deduced proteins. Hydrophobicity analysis predicted six membrane‐spanning domains flanked by hydrophilic amino and carboxy termini. A putative cyclic nucleotide binding domain (CNBD) which contains several residues that are invariant in other CNBDs was located in the carboxy terminus. This domain overlaps with a predicted calmodulin (CaM) binding site, suggesting interaction between cyclic nucleotide and CaM regulation. We demonstrated interaction of the carboxy termini of AtCNGC1 and AtCNGC2 with CaM in yeast, indicating that the CaM binding sites are functional. Furthermore, it was shown that both AtCNGC1 and AtCNGC2 can partly complement the K + ‐uptake‐deficient yeast mutant CY162. Therefore, we propose that the identified genes constitute a family of plant cyclic nucleotide‐ and CaM‐regulated ion channels.