Protein kinase Calpha puts the hand cuffs on epidermal keratinocyte proliferation.

As the predominant cellular receptor for phorbol esters, protein kinase C (PKC) is assumed to play a role in epidermal carcinogenesis. Nevertheless, determining its exact role in keratinocytes has been difficult because of the existence of multiple PKC isoforms and the inherent weaknesses in methodologies used to investigate their function. In this issue, Jerome-Morais et al. describe their use of multiple in vitro, in situ, overexpression, and knockdown approaches to demonstrate that PKCalpha induces keratinocyte growth arrest.