Cell Death and Differentiation (2005) 12, 1497–1508 & 2005 Nature Publishing Group All rights reserved 1350-9047/05 $30.00 www.nature.com/cdd Review Death penalty for keratinocytes: apoptosis versus cornification S Lippens1,2, G Denecker1, P Ovaere1, P Vandenabeele*,1 and apoptosis, necrosis or autophagy ultimately result in the W Declercq*,1 elimination of particular cells from a tissue. However, in specialized forms of differentiation, dead cell corpses are not 1 Molecular Signaling and Cell Death Unit, Department for Molecular Biomedical removed but maintained to fulfil a specific function. These Research, VIB (Flanders Interuniversity Institute for Biotechnology) and Ghent developmental cell death programs result in the production of University, Technologiepark 927, B-9052 Zwijnaarde, Belgium 2 differentiated ‘storage’ cells containing large amounts of Current address: Institute de Biochimie, Universite´ de Lausanne, Chemin des specific proteins or other substances. Examples of such Boveresses 155, CH-1066 Epalinges, Switzerland * Corresponding authors: W Declercq and P Vandenabeele, Molecular Signaling differentiation programs occur in the stalk of the slime mold and Cell Death Unit, Department of Molecular Biomedical Research, Dictyostelium, during xylogenesis in plants, erythrocyte Technologiepark 927, B-9052 Zwijnaarde, Belgium. differentiation, lens fiber formation and cornification of Tel: þ 32 9 33137 60 Fax: þ 32 9 3313609; keratinocytes in the skin. E-mails:
[email protected], Both apoptosis and keratinocyte cornification share some
[email protected] similarities at the cellular and molecular level, such as loss of an intact nucleus and other organelles, cytoskeleton and cell Received 17.6.04; revised 23.3.05; accepted 07.4.05 Edited by G Melino shape changes, involvement of proteolytic events and mitochondrial changes.