ABSTRACT
Keratins, the epithelial-predominant members of the intermediate filament superfamily, are expressed in a pairwise, tissuespecific and differentiation-dependent manner. There are 28 type I and 26 type II keratins, which share a common structurecomprising a central coiled coil a-helical rod domain flanked by two nonhelical head and tail domains. These domainsharbor sites for major posttranslational modifications like phosphorylation and glycosylation, which govern keratin functionand dynamics. Apart from providing structural support, keratins regulate various signaling machinery involved in cellgrowth, motility, apoptosis etc. However, tissue-specific functions of keratins in relation to cell proliferation and differentiation are still emerging. Altered keratin expression pattern during and after malignant transformation is reported tomodulate different signaling pathways involved in tumor progression in a context-dependent fashion. The current reviewfocuses on the literature related to the role of keratins in the regulation of cell proliferation, differentiation and transformation in different types of epithelia.