Structural comparisons of class I phosphoinositide 3-kinases

Class I phosphoinositide 3-kinases (PI3Ks) are lipid kinases that regulate cell growth. One of these kinases, PI3K alpha, is frequently mutated in diverse tumour types. The recently determined structure of PI3K alpha reveals features that distinguish this enzyme from related lipid kinases. In addition, wild-type PI3K gamma differs from PI3K alpha by a substitution identical to a PI3K alpha oncogenic mutant (His1047Arg) that might explain the differences in the enzymatic activities of the normal and mutant PI3K alpha. Comparison of the PI3K structures also identified structural features that could potentially be exploited for the design of isoform-specific inhibitors.