Planar cell polarity is the polarization of cells within the plane of a tissue. This allows the cells to obtain directional information with respect to the body axes. The Dachsous-Fat pathway plays a key role in the regulation of planar cell polarity and growth during the development of an organism. The transmembrane cadherins Fat and Dachsous from neighboring cells interact heterophilically and regulate the localization of the unconventional myosin Dachs in a cell. Four-jointed, a Golgi-localized kinase modulates the binding between Dachsous and Fat. Dachsous and Four-jointed are expressed in tissue-wide gradients, which influence Fat activity and direct the polarized membrane localization of Dachs. We have shown that Dachsous and Four-jointed gradients can be measured over long range in a tissue through propagation of polarity. We have also identified a molecular mechanism for crosstalk between the Dachsous-Fat and the Frizzled planar cell polarity pathway. These studies help in understanding the mechanisms involved in establishment and maintenance of planar cell polarity.