Chapter 3: acquisition of membrane polarity in epithelial tube formation patterns, signaling pathways, molecular mechanisms, and disease.

Epithelia coordinate the polarity of individual cells, in space and time, with surrounding cells and the extracellular matrix (ECM) to organize three-dimensional structures that shape tissues and organs. One of the most important features of epithelial polarization is the asymmetric distribution of membrane surfaces with the apical surface facing a lumen or outside of the organism, and a basolateral surface facing other cells and ECM. This chapter discuss the processes required for the acquisition of the asymmetric distribution of membrane surfaces during morphogenesis, which include trafficking pathways, vesicle-sorting machineries, formation of junctional and polarity complexes, and the establishment of signaling networks. In addition, different mechanisms and patterns are described for forming luminal spaces, and how alterations in cell polarity are associated with important human diseases such as cancer.