Epithelial cell shape and Rho small GTPases.

In epithelial cells, morphology is intrinsically related to function. Typically, polarization (i.e. acquisition of a cuboidal cell shape) must occur prior to terminal differentiation and functionality of epithelial sheets. Extensive work has been performed to understand the initial steps that drive cell-cell contact assembly, a process that is essential for polarization. However, not much is known about the subsequent steps that lead to remodelling of actin cytoskeleton and concomitant cell shape changes. Here we review what is known about actin organization during epithelial polarization, and discuss current models for junction assembly, actin reorganization and signalling pathways that may contribute to the generation of a polarized epithelial morphology.