Motors Based on Actomyosin

Abstract

Engines or motors based upon actin and myosin are probably the most common amongst eukaryotic cells; the components required are found in almost all the cell types that have been investigated although the activity of the motor has only been demonstrated in a few cases. The way in which the components of the motor are arranged does vary, according to the task for which it is used, but the basic principle of its operation is assumed to remain more-or-less constant. The mechanism by which the motor operates is normally introduced by discussing the mechanism of force generation in vertebrate striated muscle, partly because this is the best understood and best studied example, and partly because historically it was the first such system to be worked out. In some ways this is unfortunate because it has led to the feeling, frequently not recognized or acknowledged explicitly, that all other forms of the motor are degenerate examples of striated muscle. Nothing could be further from the truth; striated muscle is merely a very specialized form, a highly-tuned engine using the motor for a simple and clearly defined task, of generating tension in a linear fashion.