Contribution of Ref(2)p to regulation of Drosophila notum epithelial cell apico-basal polarity and phenotype

Cell polarity impacts on the maintenance of cell shape, cell-cell junction integrity, and protrusion formation and dynamics. Further, polarity additionally regulates cell movement, proliferation and differentiation. Conversely when cells lose their polarity they may be susceptible to dysfunction that may underlie degenerative disorders. Cell polarity and polarity protein complexes are highly conserved between different organisms from unicellular to multi-cellular, and from invertebrates to vertebrates. The focus of this study is the apico-basal polarity that is established normally in epithelial cells. p62 is a multifunctional scaffold protein which acts as a signalling hub for different pathways, and through interactions with the polarity protein aPKC we hypothesise that it may regulate apico-basal polarity. Ref(2)p is the Drosophila homologue of p62 and using Drosophila as a model system we are investigating the effects of Ref(2)p mutation or expression levels on apico-basal polarity, cell shape and protrusion dynamics in the epithelial cells of the dorsal thorax. Our preliminary data suggest that Ref(2)p is required to maintain normal cell size, cell-cell junctions and protrusion dynamics. Mechanistically, these phenotypes may be due to Ref(2)p’s interaction with polarity proteins or broader changes in Ref(2)p-mediated autophagy