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Getting a Grip on Myosin Review
| Content Provider | Semantic Scholar |
|---|---|
| Author | Vale, Ronald D. |
| Copyright Year | 1994 |
| Abstract | The biochemistry of muscle contraction is taught in every introductory biology class, and hence many people believe that myosin force transduction is well understood. However, although it is firmly established that actin and myosin filaments slide past one another in a muscle sarcomere, the molecular mechanism of myosin motility has become a subject of increasing controversy. The debate has been fueled, in part, by measurements of how far myosin can move along an actin filament during one round of ATP hydrolysis. Values varying from 5 to 200 nm per ATP have emerged from such studies, and, not surprisingly, radically different models of myosin-based movement have been presented to account for these results. The wide variation of myosin step size estimates very likely stems from the fact that the measurements were indirect and the number of force-generating myosins interacting with actin was not precisely known (reviewed by Burton, 1992). Clearly, a direct measurement of forces and displacements from a single myosin molecule was needed, but such experiments presented a daunting challenge. The forces produced by a single myosin are thought to be only a few picoNewtons, which is about 1000-fold less than the gravitational attraction between the reader and this issue of Cell held at arms' length. How can such minute mechanical events be measured? Two groups, led by J. Spudich (Finer et al., 1994) and T. Yanagida (Ishijima et al., 1994), have now developed fascinating microscopic technologies to measure forces and displacements of single myosin molecules in the millisecond time domain. While these groups have differed in the past on their measurements of myosin step sizes, their direct measurements using very different assay systems have yielded comfortingly similar answers. These studies, along with other recent work on kinesin (Svoboda et al., 1993; Svoboda and Block, 1994; Malik et al., 1994) and myosin (Miyata et al., 1994), have opened up new directions for examining motor proteins; the impact of these developments should be comparable to that which patch clamping has made on the ion channel field. These recent experiments also raise questions of how myosin and other molecular motors work, as discussed below. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://valelab4.ucsf.edu/external/publications/1994valecell.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
