RT Journal
A1 Leonard, Christopher J.
A1 Aravind, L.
A1 Koonin, Eugene V.
T1 Novel Families of Putative Protein Kinases in Bacteria and Archaea: Evolution of the “Eukaryotic” Protein Kinase Superfamily
JF Genome Research 
JO Genome Research 
YR 1998 
FD October 01 
VO 8 
IS 10 
SP 1038 
OP 1047 
DO 10.1101/gr.8.10.1038 
UL http://genome.cshlp.org/content/8/10/1038.abstract 
AB The central role of serine/threonine and tyrosine protein kinases in signal transduction and cellular regulation in eukaryotes is well established and widely documented. Considerably less is known about the prevalence and role of these protein kinases in bacteria and archaea. In order to examine the evolutionary origins of the eukaryotic-type protein kinase (ePK) superfamily, we conducted an extensive analysis of the proteins encoded by the completely sequenced bacterial and archaeal genomes. We detected five distinct families of known and predicted putative protein kinases with representatives in bacteria and archaea that share a common ancestry with the eukaryotic protein kinases. Four of these protein families have not been identified previously as protein kinases. From the phylogenetic distribution of these families, we infer the existence of an ancestral protein kinase(s) prior to the divergence of eukaryotes, bacteria, and archaea.