Pleckstrin homology domain of the Drosophila melanogaster step gene. This domain binds specifically to phosphatidylinositol 3,4,5-trisphosphate (FBrf0210551). This domain can thus be used to monitor the distribution of phosphatidylinositol 3,4,5-trisphosphate within a cell, if fused to an appropriate reporter protein or to target a tagged protein to a particular subcellular localization via phosphatidylinositol 3,4,5-trisphosphate binding.