Cover: Scanning electron micrograph of the epidermal epithelium of adult zebrafish (Danio rerio). The distinctive labyrinth-like patterns seen on most of the cells are actin micro-ridges that are characteristic of superficial keratinocytes. In response to injury, directed migration of keratinocytes into the wound promotes healing. This process requires keratinocytes to sense and respond to chemical and physical cues in their external environment. In isolated zebrafish keratinocytes, Ca2+ influx is required for polarity and migration, and appears to occur through mechanically activated channels, including several transientreceptorpotential family members such as TRPV1. Moreover, cell motility and intracellular Ca2+ levels are affected by pharmacological agents that target TRPV1, indicating a new role for this channel during cell migration. See article by D. M. Graham et al. (pp 4602–4613).