Y (2011) Cellular functions of class IX myosins in epithelia and immune cells. Biochem Soc Trans 39: 1166

Abstract

Abstract Mammals contain two class IX myosins, Myo9a and Myo9b. They are actin-based motorized signalling molecules that negatively regulate RhoA signalling. Myo9a has been implicated in the regulation of epithelial cell morphology and differentiation, whereas Myo9b has been shown to play an important role in the regulation of macrophage shape and motility. Class IX myosins Helical actin filaments can serve as tracks for molecular motors owing to their polar structure. The actin-based molecular motors constitute the myosin superfamily. Members of this superfamily share a region with similar amino acid sequences that defines the motor region. Based on sequence similarities, the myosins have been grouped into different classes. Class IX myosins consist of a single member in invertebrates and of two members in mammals, called Myo9a (myr 7) and Myo9b (myr 5). As in the case of all myosin molecules, class IX myosins are composed of a motor region, a light-chain-binding region and a tail regio