UASt regulates expression of an extracellular truncation of N that that has undergone ADAM10 cleavage (S2 cleavage) and becomes a substrate for gamma-secretase (depends on S3 cleavage). FlyBase curator comment: the expressed protein is not tagged with HA even though the transgene was generated using the pUASg-HA.attB plasmid, as the ORF contains a stop codon (see FBrf0252879).