title: P21Waf1 control of epithelial cell cycle and cell fate.
abstract: As a broad-acting cyclin-dependent kinase inhibitor, p21(WAF1) occupies a central position in the cell cycle regulation of self-renewing tissues such as oral mucosa and skin. In addition to regulating normal cell cycle progression decisions, p21(WAF1) integrates genotoxic insults into growth arrest and apoptotic signaling pathways that ultimately determine cell fate. As a result of its complex interactions with cell cycle machinery and response to mutagenic agents, p21(WAF1) also has stage-specific roles in epithelial carcinogenesis. Finally, a view is emerging of p21(WAF1) as not merely a cyclin-dependent kinase inhibitor, but also as a direct participant in regulating genes involved in growth arrest, senescence, and aging, thus providing an additional layer of control over matters of the cell cycle. This review discusses these various roles played by p21(WAF1) in cell cycle control, and attempts to relate these to epithelial cell biology, with special emphasis on keratinocytes.
authors.affiliation: Laboratory of Immunobiology, Division of Monoclonal Antibodies, Center for Biologics Evaluation and Research, FDA, NIH Bldg 29B, Room 3NN04, HFM-564, Bethesda, MD 20892, USA. weinberg@cber.fda.gov
authors.forename: Wendy C
authors.initials: WC
authors.lastname: Weinberg
authors.forename: Mitchell F
authors.initials: MF
authors.lastname: Denning
mesh_terms: D017209:Apoptosis / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D016213:Cyclins / Q000235:genetics / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004847:Epithelial Cells / Q000502:physiology; D005786:Gene Expression Regulation; D006801:Humans; D015603:Keratinocytes / Q000502:physiology; D009061:Mouth Mucosa / Q000166:cytology; D009153:Mutagens / Q000494:pharmacology; D009369:Neoplasms / Q000473:pathology; D012867:Skin / Q000166:cytology
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D009153:Mutagens; D018844:Cyclin-Dependent Kinases