Phosphoinositides (PIs), phosphorylated derivatives of phosphatidylinositol (PtdIns), control cellular functions through recruitment of cytosolic proteins to specific membranes. Among the kinases involved in PI generation, the PI3K-III complex, which catalyzes conversion of PtdIns into PtdIns 3-phosphate (PI3P), is of great interest for several reasons. Firstly, it is required for three topologica ...