Cell polarity in eggs and epithelia: parallels and diversity

Cell polarity, the generation of cellular asymmetries, is necessary for diverse processes in animal cells, such as cell migration, asymmetric cell division, epithelial barrier function, and morphogenesis. Common mechanisms generate and transduce cell polarity in different cells, but cell type-specific processes are equally important. In this review, we highlight the similarities and differences between the polarity mechanisms in eggs and epithelia. We also highlight the prospects for future studies on how cortical polarity interfaces with other cellular processes, such as morphogenesis, exocytosis, and lipid signaling, and how defects in polarity contribute to tumor formation.