Beta-keratin Beta-keratin β-keratin or beta-keratin is a member of a structural protein family found in the epidermis of reptiles and birds . β-keratins were named so because they are components of epidermal stratum corneum rich in stacked β pleated sheets, in contrast to alpha-keratins, intermediate-filament proteins also found in stratum corneum and rich in alpha helices. Because the accurate use of the term "keratin" is limited to the alpha-keratins, the term "beta-keratins" in recent works is replaced by "corneous beta-proteins" or "keratin-associated beta-proteins". β-keratins add much more rigidity to reptilian skin than alpha-keratins alone do to mammalian skin. β-keratins are impregnated
Myosin cells, the long coiled-coil tails of the individual myosin molecules join together, forming the thick filaments of the sarcomere. The force-producing head domains stick out from the side of the thick filament, ready to walk along the adjacent actin-based thin filaments in response to the proper chemical signals. Myosin III is a poorly understood member of the myosin family. It has been studied "in vivo" in the eyes of "Drosophila", where it is thought to play a role in phototransduction. A human homologue gene for myosin III, MYO3A, has been uncovered through the Human Genome Project and is expressed in