A conserved signaling cassette regulates hair patterning from Drosophila to man

摘要

The establishment and maintenance of cellular polarization is of critical importance for the proper development and functioning of an organ. Cells in many distinct contexts show different aspects of polarization. Apical-basolateral polarity, for example, is evident in all epithelial cells. Additionally, some epithelial cell types are also polarized within the plane of the epithelium, perpendicular to the apical-basal axis. This type of polarity is referred to as tissue polarity or planar cell polarity (PCP) (reviewed in ref. 1). PCP has been most frequently studied and is best understood in Drosophila, where all adult epithelial cuticular structures are polarized within the plane. Studies in Drosophila led to the identification of the Frizzled (Fz) receptor and the associated Fz/PCP signaling pathway as key mediators regulating this process (reviewed in refs. 2 and 3). Recently, PCP signaling has also been studied in vertebrates, with emphasis on the polarization of the sensory cells in the inner ear epithelium and the morphology and behavior of mesenchymal cells undergoing the morphogenetic process of convergent extension during gastrula-tion.