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