We have characterised the function of two Drosophila genes, miniature and dusky, that are required for the morphological reorganisation of the apical membrane during wing epidermis differentiation. These genes encode transmembrane proteins containing a ZP (zona pellucida)domain and are homologous to several vertebrate and invertebrate apical matrix components. miniature and dusky are only expressed in tissues secreting a cuticle, and the Min protein localises to the apical membrane during the early stages of cuticle formation. We propose that Min and Dusky form a novel subfamily within the ZP domain proteins and are specifically involved in the interactions between the apical membrane, the cytoskeleton and the forming cuticle.