Going Multicellular with a Beefed-Up Kinome

Science Signaling  21 Oct 2008:
Vol. 1, Issue 42, pp. ec366
DOI: 10.1126/scisignal.142ec366

Protein kinases that catalyze covalent modification of other proteins by phosphorylation of serine, threonine, or tyrosine residues provide a major mechanism for control of cellular processes in eukaryotes. The roles of these enzymes in prokaryotes, however, have been less evident. The abundance of newly sequenced genomes allowed Perez et al. to analyze the kinomes of more than 600 prokaryotic genomes. The authors’ bioinformatic analysis, with particular focus on sequences from seven strains of myxobacteria, showed that two-thirds of the prokaryotes had eukaryotic-like kinases (ELKs). The largest numbers of ELKs were found in the myxobacteria, which interact with one another to hunt in swarms and undergo multicellular developmental programs in response to starvation. The repertoire of nearly 900 ELKs in these bacteria rivals the genomic density of such enzymes in eukaryotes. The myxobacterial enzymes had modular organization that included domains with sequence similarity to domains used in protein interactions and signaling mechanisms of eukaryotic cells. The authors propose that the expansion of ELKs in myxobacteria, which was greater than that of two-component systems (bacterial signaling systems that use histidine kinases), may have allowed more sophisticated signaling systems compatible with the more complicated life-style of these bacteria, which requires them to sense other cells and coordinate their behavior with them, thus providing an important step on the way to formation of multicellular eukaryotic organisms.

J. Pérez, A. Castañeda-García, H. Jenke-Kodama, R. Müller, J. Muñoz-Dorado, Eukaryotic-like protein kinases in the prokaryotes and the myxobacterial kinome. Proc. Natl. Acad. Sci. U.S.A. 105, 15950-15955 (2008). [Abstract] [Full Text]