Cytoskeletal Mechanics: Models and Measurements
With contributions from the biophysics, bioengineering, and physical chemistry communities, this book presents a full spectrum of views on current approaches to modeling cell mechanics.
TABLE OF CONTENTS Cytoskeletal Mechanics: Models and Measurements
Actin Dynamics
Abundant, essential, and discovered more than a half-century ago, actin is one of the most studied of all the proteins. Many investigations have focused on the dynamic character of actin, leading to a rich quantitative understanding of actin assembly and disassembly. In this section we briefly review this history and summarize the modern understanding of actin dynamics and its regulation by key binding proteins.
The emergence of actin dynamics
The appreciation that actin has both dynamic and mechanical properties can be traced to the work of its discoverer, F.B. Straub (Mommaerts, 1992). Trying to understand the difference between a highly viscous mixture of myosin B and a less viscous mixture of myosin A, Straub discovered these were not different myosins at all, but that the myosin B preparations were contaminated by another protein that ACTivated myosIN to make the viscous solution (Feuer et al., 1948). Straub s laboratory later revealed that the contaminating actin could itself convert between low- and high-viscosity solutions with the introduction of physiological salts and/or ATP (Straub and Feuer, 1950). Further data from Straub demonstrated that the phase change occurred because a globular protein ( G-actin ) polymerized into long filaments ( F-actin ) and that the filamentous form could hydrolyze ATP. With the discovery of sarcomere structure (Huxley and Hanson, 1954) and the sliding filament model of muscle contraction in the 1950 s (Huxley, 1957), actin s role as the structural thin filament of muscle was in place. The significance of actin s dynamic properties, however, remained unclear.
Over the...
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