Epithelial differentiation proceeds in at least two steps: Conversion of a nonepithelial cell
into an epithelial sheet followed by terminal differentiation into the mature epithelial
phenotype. It was recently discovered that the extracellular matrix (ECM) protein hensin is
able to convert a renal intercalated cell line from a flat, squamous shape into a cuboidal or
columnar epithelium. Global knockout of hensin in mice results in embryonic lethality at the
time that the first columnar cells appear. Here, antibodies that either activate or block integrin …