Acts in a planar cell polarity (PCP) complex; polarization along the apical/basal axis of epithelial cells. Regulates the polarized assembly of fibronectrin on the surface of the mesoderm during gastrulation. Essential for gastrulation cell movements, cooperating with dvl2/dsh to activate jnk. Acts together with tes to control axial elongation. Interacts with dvl2/dsh and mapk8/jnk1. Expressed in the dorsal marginal zone of early gastrulae (stage 10). As gastrulation proceeds, expression expands to include the lateral and ventral marginal zones, excluding the few rows of cells above the blastopore lip. Expression moves dorsally with gastrulation cell movements, and by the end of gastrulation expression is seen in dorsal mesoderm and posterior but not anterior neural ectoderm. Expression becomes down-regulated in mesoderm but remains strong in posterior ectoderm through the neurula stages. During tailbud stages, expressed in the pronephric duct, tailbud, tailtip and forming somites. In the most posterior regions, expressed in notochord and in the floorplate of the neural tube with weak expression in the roofplate. At stage 30, expressed in a complex pattern in the head including strong expression in the lens and otic vesicle. Expressed both maternally and zygotically. Zygotic expression begins at the onset of gastrulation (stage 10), and steadily increases until tadpole stage (stage 30). Belongs to the prickle / espinas / testin family.