Sorting out the p63 signaling network.

p63 is a transcription factor required for normal epidermal development and differentiation. Because of the complexity of these processes, p63 is expected to regulate a myriad of target genes, providing impetus to many laboratories to identify these genes. p63 target genes have been shown to encode a diverse group of proteins, including structural proteins, proteins that control cell cycle withdrawal, and proteins that regulate the epidermal differentiation program. In this issue, Antonini et al., describe a novel p63 target gene whose evolutionary conservation suggests a critical role for this gene in the epidermis.