Spectrin: the ghost in the machine

It has long been speculated that spectrin, the actin crosslinking and molecular scaffold protein, is involved in the development of apicobasal polarity in epithelia. While spectrins can undoubtedly influence the protein content of specific membrane domains, recent genetic evidence indicates that this activity is not necessary for the establishment or maintenance of this axis. Instead, these studies point to critical roles in tissue stability and morphogenesis. A possible role in cellular contractility is highlighted in this review.