SURVEY, ANALYSIS AND GENETIC ORGANIZATION OF GENES ENCODING EUKARYOTIC-LIKE SIGNALING PROTEINS ON A CYANOBACTERIAL GENOME

Bacteria usually use two-component systems for signal transduction, wh ile eukaryotic organisms employ Ser/Thr and Tyr kinases and phosphatas es for the same purpose. Many prokaryotes turn out to harbor Ser/Thr a nd Tyr kinases, Ser/Thr and Tyr phosphatases, and their accessory comp onents as well, The sequence determination of the genome of the cyanob acterium Synechocystis sp, strain PCC 6803 offers the possibility to s urvey the extent of such molecules in a prokaryotic organism, This cya nobacterium possesses seven Ser/Thr kinases, seven Ser/Thr and Tyr pho sphatases, one protein kinase interacting protein, one protein kinase regulatory subunit and several WD40-repeat-containing proteins. The ma jority of the protein phosphatases presented in this study were previo usly reported as hypothetical proteins, We analyze here the structure and genetic organization of these ORFs in the hope of providing a guid ance for their functional analysis, Unlike their eukaryotic counterpar ts, many of these genes are clustered on the chromosome, and this gene tic organization offers the opportunity to study their possible intera ction. In several cases, genes of two-component transducers are found within the same cluster as those encoding a Ser/Thr kinase or a Ser/Th r phosphatase; the implication for signal transduction mechanism will be discussed.