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
Alpha-keratin of most biological importance of alpha-keratin is its structural stability. When exposed to mechanical stress, α-keratin structures can retain their shape and therefore can protect what they surround. Under high tension, alpha-keratin can even change into beta-keratin, a stronger keratin formation that has a secondary structure of beta-pleated sheets. Alpha-keratin tissues also show signs of viscoelasticity, allowing them to both be able to stretch and absorb impact to a degree, though they are not impervious to fracture. Alpha-keratin strength is also affected by water content in the intermediate filament matrix; higher water content decreases the strength and stiffness of the