The Dictyostelium Kinome
Dictyostelium discoideum is a simple model organism that diverged from the animal lineage after the split from plants, but before fungi. As a largely single-celled organism that forms multicellular fruiting bodies, it is fascinating both for its evolutionary position, as well as being a simple model to study intercellular communiation and co-ordination, movemenent and development.
In March 2006, we published a detailed analysis of the kinome of Dictyostelium (known affectionately as 'Dicty'), as a collaboration between the Boston Biomedical Research Institute (BBRI) and the Salk Institute, with help from the Dictybase database:
In brief, Dicty has 285 protein kinases, a similar proportion of the genome as several other eukaryotes. Surprisingly, it has members of 24 subfamilies (Table 1) not found in yeast, even though Dictyostelium is more evolutionarily divergent than fungi. This suggests that these kinases were present in very early eukaryotes, but lost from fungi, due to their simpler lifestyle.
While Dicty, like yeast, lacks the tyrosine kinase (TK) group, it has a greatly expanded TKL (tyrosine kinase like) group, which for the first time includes kinases that have been shown to have tyrosine kinase activity, and include putative receptor tyrosine kinases. This suggests that the sequence and structural similarities between TK and TKL may have a functional basis (ability to phosphorylate tyrosine) and an evolutionary basis, where the TK group may have evolved from the ancient TKL group.
Dictyostelium shines light on several other aspects of kinase evolution and function, and also raises many new questions - check out the full paper if you are interested. The supporting data is now also available through our KinBase database.