Keratin 19 Keratin 19 Keratin, type I cytoskeletal 19 also known as cytokeratin-19 (CK-19) or keratin-19 (K19) is a 40 kDa protein that in humans is encoded by the "KRT19" gene. Keratin 19 is a type I keratin. Keratin 19 is a member of the keratin family. The keratins are intermediate filament proteins responsible for the structural integrity of epithelial cells and are subdivided into cytokeratins and hair keratins. Keratin 19 is a type I keratin. The type I cytokeratins consist of acidic proteins which are arranged in pairs of heterotypic keratin chains. Unlike its related family members, this smallest known acidic
Myosin head although some forms have a globular region in their C-terminal. There are many cell-specific isoforms of myosin heavy chains, coded for by a multi-gene family. Myosin interacts with actin to convert chemical energy, in the form of ATP, to mechanical energy. The 3-D structure of the head portion of myosin has been determined and a model for actin-myosin complex has been constructed. The globular head is well conserved, and is key to contraction. Muscle contraction results from an attachment–detachment cycle between the myosin heads extending from myosin filaments and the sites on actin filaments. The myosin head first attaches to