Keratin 5 to withstand mechanical, and non-mechanical, stresses. K5/K14 keratin pairs are able to undergo extensive bundling due to the non-helical tail of K15 acting as a weak cross-linker at the intermediate filament surface. This bundling increases the elasticity, and therefore the mechanical resilience, of the intermediate filaments. K5/K14 intermediate filaments are anchored to the desmosomes of basal cells via desmoplakin and plakophilin-1, connecting the cells to their neighbours. At the hemidesmosome, plectin and BPAG1 associate with transmembrane proteins α6β4 integrin, a type of cell adhesion molecule, and BP180/collagen XVII, linking K5/K14 filaments in the basal cells to the basal lamina. Epidermolysis
Keratin used as fluorescent markers to distinguish subsets of TECs in genetic studies of the thymus. Additionally, the baleen plates of filter-feeding whales are made of keratin. Keratins (also described as cytokeratins) are polymers of type I and type II intermediate filaments, which have only been found in the genomes of chordates (vertebrates, Amphioxus, urochordates). Nematodes and many other non-chordate animals seem to only have type VI intermediate filaments, lamins, which have a long rod domain (vs. a short rod domain for the keratins). The human genome encodes 54 functional keratin genes which are located in two clusters on chromosomes 12