Required for polarization of the embryonic, imaginal disk and follicular epithelia. Specifically restricts apical membrane determinants to the apical cell surface; acts to exclude crb from the basolateral domain and define adherens junction position. Regulates cellular growth and differentiation; acts as a tumor suppressor. Essential for odor guided behavior. Localized to epithelial septate junction at the boundary of the apical and basolateral cell surfaces. During germ band extension, expression of isoform A occurs predominantly in neuroblasts derived from the neuro-ectoderm and later is restricted to CNS neurons and pole cells. Isoform C is strongly expressed in PNS and a subset of CNS neurons. In the adult, expressed in third antennal segment and maxillary palps, major olfactory organs and in Johnstons organ in the second antennal segment. Expression is also observed in cortical regions of the brain. Isoforms expressed in epithelia are coexpressed with dlg1 throughout development. Expressed both zygotically and maternally in embryos. Isoform A and isoform C have high expression throughout embryonic development and very low expression in later developmental stages. In adults, isoform A is a male-specific isoform and isoform C a female specific. Flies exhibit aberrant cell shape and loss of the monolayer organization of embryonic epithelia creating a corrugated cuticular surface that is riddled with holes hence the gene name scribble. Misdistribution of apical proteins and adherens junctions to the basolateral cell surface is also exhibited. Belongs to the LAP (LRR and PDZ) protein family. Probable cloning artifact.