(A) Conserved domain structure of a putative cyclic nucleotide dependent plant kinase. So far, it has been impossible to assign genuine kinase activity to this protein. Interestingly, a PP2C phosphatase moiety is also present in the same open reading frame but its functionality and significance are yet unknown. (B) A single copy gene is present in Arabidopsis thaliana, whereas homologous genes are found in the dicot Ricinus comunis, in the monocot Oryza sativa, in the moss Physcomitrella patens, and in the green alga Ostreococcus tauri. ‘PP2C’: phosphatase 2C; ‘CNBD’: cyclic nucleotide binding domain.