Keratin 5 Keratin 5 Keratin 5, also known as KRT5, K5, or CK5, is a protein that is encoded in humans by the "KRT5" gene. It dimerizes with keratin 14 and forms the intermediate filaments (IF) that make up the cytoskeleton of basal epithelial cells. This protein is involved in several diseases including epidermolysis bullosa simplex and breast and lung cancers. Keratin 5, like other members of the keratin family, is an intermediate filament protein. These polypeptides are characterized by a 310 residue central rod domain that consists of four alpha helix segments (helix 1A, 1B, 2A, and 2B) connected by three
Myosin head actin together with the products of ATP hydrolysis, performs a power stroke associated with release of hydrolysis products, and detaches from actin upon binding with new ATP. The detached myosin head then hydrolyses ATP, and performs a recovery stroke to restore its initial position. The strokes have been suggested to result from rotation of the lever arm domain around the converter domain, while the catalytic domain remains rigid. Myosin head Muscle contraction is caused by the sliding action of thick filaments over thin filaments of the myofibril. Myosin is a major component of thick filaments and most myosin molecules are