Spiny legs and prickled bodies: new insights and complexities in planar polarity establishment

Epithelial cells can be polarized along two axes, namely in the apical-baso lateral axis and in the horizontal plane of the epithelium. Vertebrate exam ples of planar polarization include aspects of skin development or features in internal organs, such as the inner ear epithelium. In insects like Dros ophila, adult cuticular structures show planar polarization. Studies on pla nar polarity in Drosophila have identified several genes that regulate this process. Notably, the Frizzled receptor and its signaling cascade provide an entry point to the molecular aspects of planar polarization. A recent st udy by Gubb et al.((1)) of the prickle locus, which encodes a cytoplasmic p rotein with three LIM domains, provides new insights and raises several int eresting questions that can now be addressed. Pk might serve a scaffolding function involved in assembling a protein complex required for planar polar ity establishment. BioEssays 22:311-315, 2000. (C) 2000 John Wiley & Sons, Inc.