UASt regulatory sequences drive expression of shg in which a conserved triplet of Gly resides in the juxtamembrane region has been mutated to a triplet of Ala residues (the equivalent mutation in the human ortholog disrupts the interaction with p120ctn but does not affect the interaction with &bgr-catenin).
When shgGGG-AAA.Scer\UAS is driven by Scer\GAL4btl.PS tracheal development appears unaffected.