Keratin 6A and keratin 6C are encoded by the neighbouring genes, which are identical in intron-exon organization to "KRT6A" and are more than 99% identical in their DNA coding sequences. Mutations in the genes expressing this protein is associated with the PC-K6A subtype of pachyonychia congenita, an inherited disorder of the epithelial tissues in which keratin 6A is expressed, particularly leading to structural abnormalities of the nails, the epidermis of the palms and soles, and oral epithelia. Keratin 6A Keratin 6A is one of the 27 different type II keratins expressed in humans. Keratin 6A was the first type II keratin sequence
Myosin head 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 composed of a head, neck, and tail domain; the myosin head binds to thin filamentous actin, and uses ATP hydrolysis to generate force and "walk" along the thin filament. Myosin exists as a hexamer of two heavy chains, two alkali light chains, and two regulatory light chains. The heavy chain can be subdivided into the globular head at the N-terminal and the coiled-coil rod-like tail at the C-terminal,