Motility is a fundamental property of living systems, from the cytoplasmic streaming of unicellular organisms to the most highly differentiated and de- veloped contractile system of higher organisms, striated muscle. Although of motility have a long and in- scientific investigations into the mechanisms teresting history, the knowledge of molecular processes, especially in the area of regulation of control of motility, has been developing at an ever more rapid pace with the utilization of multidisciplinary approaches from physiology, cell biology, genetics, biochemistry, pharmacology, and...

The preceding volumes of Cell and Muscle Motility have focused on various aspects of motile systems in both muscle and non muscle cells. These essays have been critical reviews on topics of current interest and, hopefully, have provided a base from which future investigations may develop. During the past decade, however, much attention in the fields of biochemistry and cell biology has focused on motile systems in non muscle cells. Our current under- standing of the three-dimensional organization of the cytoplasm involve three major fibrous proteins which are collectively known as the...

The term cytoskeleton in muscle and nonmuscle cells refers to fibrous proteins that are directly or indirectly associated with cell shape, contractility, and/or motility. These cytoskeletal elements include microtubules and associated proteins, microfilaments and their binding proteins, and lastly, intermediate filaments. Even though the structure and function of myosin and tro- pomyosin have been extensively investigated in muscle ceIls, considerably less is known about their functions in nonmuscle ceIls; they are often referred to generically as actin-binding proteins, as are a-actinin,...