The Tag:P4M(Unk) entry in FlyBase represents sequence that binds specifically to phosphatidylinositol 4-phosphate, where the species and/or gene of origin are unknown. This domain can 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.