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Sci. Signal., 1 May 2012
Vol. 5, Issue 222, p. ra35
Tracing Tyrosine Kinase Evolution
Protein tyrosine kinases, which are involved in diverse cellular functions, are broadly classified as cytoplasmic tyrosine kinases and receptor tyrosine kinases. Because tyrosine kinases played important roles in the evolution of multicellular organisms, Suga et al. investigated the evolution of this group of kinases by performing a genomic screen of the tyrosine kinase–encoding genes of the only two known members of the Filasterea, a type of single-celled eukaryote. Through phylogenetic analysis and by comparing tyrosine kinase–encoding sequences from the Filasterea with those from other organisms, such as animals (metazoans) and choanoflagellates (unicellular organisms considered to be the closest relatives to metazoans), the authors showed that cytoplasmic tyrosine kinases were established and diversified before the divergence between the Filasterea, choanoflagellates, and metazoans, whereas receptor tyrosine kinases evolved rapidly and separately in each of the three lineages after their split. The differences in the speed and mode of evolution between cytoplasmic tyrosine kinases and receptor tyrosine kinases raise interesting questions about the roles of these tyrosine kinases in unicellular organisms.
Citation: H. Suga, M. Dacre, A. de Mendoza, K. Shalchian-Tabrizi, G. Manning, I. Ruiz-Trillo, Genomic Survey of Premetazoans Shows Deep Conservation of Cytoplasmic Tyrosine Kinases and Multiple Radiations of Receptor Tyrosine Kinases. Sci. Signal.5, ra35 (2012).