The quest for the function of simple epithelial keratins.
Simple epithelial keratins K8 and K18 are components of the intracellular cytoskeleton in the cells of the single-layered sheet tissues inside the body. As members of the intermediate filament family of proteins, their function has been a matter for debate since they were first discovered. Whilst there is an indisputable case for a structural cell-reinforcing function for keratins in the mutilayered squamous epithelia of external barrier tissues, some very different stress-protective features now seem to be emerging for the simple epithelial keratins. Even the emerging evidence of pathological mutations in K8/K18 looks very different from mutations in stratified epithelial keratins. K8/K18-like keratins were probably the first to evolve and, whilst stratified epithelial (keratinocyte) keratins have diversified into a large group of keratins highly specialised for providing mechanical stability, the simple epithelial keratins have retained early features that may protect the internal epithelia from a broader range of stresses, including osmotic stress and chemical toxicity.
Owens
Dewi W
DW
Cancer Research UK Cell Structure Research Group, School of Life Sciences, University of Dundee, Scotland. d.w.owens@dundee.ac.uk
Lane
E Birgitte
EB
D000818:Animals; D017209:Apoptosis; D005075:Biological Evolution; D004848:Epithelium / Q000033:anatomy & histology / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D007633:Keratins / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008954:Models, Biological; D009154:Mutation; D009369:Neoplasms / Q000235:genetics / Q000503:physiopathology; D012873:Skin Diseases, Genetic / Q000235:genetics / Q000503:physiopathology
D007633:Keratins