The serine, threonine, and/or tyrosine-specific protein kinases and protein phosphatases of prokaryotic organisms: a family portrait

Inspection of the genomes For the bacteria Bacillus subtilis 168, Borrelia burgdorferi B31, Escherichia coli K-12, Haemophilus influenzae KW20, Helico bacter pylori 26695, Mycoplasma genitalium G-37, and Synechocystis sp PCC 6 803 and for the archaeons Archaeoglobus fulgidus VC-16 DSM4304, Methanobact erium thermoautotrophicum delta H, and Methanococcus jannaschii DSM2661 rev ealed that each contains at least one ORF whose predicted product displays sequence features characteristic of eukaryote-like protein-serine/threonine /tyrosine kinases and protein-serine/threonine/tyrosine phosphatases. Ortho logs for all four major protein phosphatase families (PPP, PPM, conventiona l PTP, and low molecular weight PTP) were present in the bacteria surveyed, bur not all strains contained all types. The three archaeons surveyed lack ed recognizable homologs of the PPM family of eukaryotic protein-serine/thr eonine phosphatases: and only two prokaryotes were found to contain ORFs fo r potential protein phosphatases from ail four major families, intriguingly , our searches revealed a potential ancestral link between the catalytic su bunits of microbial arsenate reductases and the protein-tyrosine phosphatas es I they share similar ligands (arsenate versus phosphate) and features of their catalytic mechanism (formation of arseno- versus phosphocysteinyl in termediates). II appears that all prokaryotic organisms, at one time, conta ined the genetic information necessary to construct protein phosphorylation -dephosphorylation networks that target serine, threonine, and/or tyrosine residues on proteins, However, the potential for functional redundancy amon g the four protein phosphatase families has led many prokaryotic organisms to discard one, two, or three of the four. (C) 1998 Published by Elsevier S cience B.V. All rights reserved.