Required in determination of cell fate during sensory organ formation in embryos (PubMed:2752427). Restricts developmental potential and promote maturation of intermediary neuronal progenitor (INP) cells probably acting as an antagonist of Notch signaling (PubMed:24550111, PubMed:28899667, PubMed:18342578). Interacts with Nak. In larval brain, shows asymmetric localization and asymmetrically sized divisions in type II secondary neuroblasts. PTB domain recognizes multiple ligands by engaging different amounts of surface area dictated by tertiary contacts rather than primary sequence. This may allow interactions with a diverse set of proteins during asymmetric division and specification of cell fate. The phospho-regulated basic and hydrophobic (PRBH) motif is necessary and sufficient for interaction with phospholipids permitting cortical localization (PubMed:26481050). Phosphorylation of the PRBH motif by aPKC inhibits the association of the protein with the cortical membrane (PubMed:26481050). Phosphorylated by aPKC which lowers lipid affinity and promotes dissociation from the cell cortex. In larval brain, leads to overgrowth and defective differentiation halting the development of secondary neuroblasts beyond the stage of immature type II intermediary neuronal progenitors (INP). Truncated N-terminus.