A new view of how muscles generate movement

2020

Challenge

For well over a hundred years, scientists thought that muscle cells are made up of many individual tube-like structures called myofibrils that contract and expand in a straight line along the length of the cell. Images of this fundamental muscle cell structure, which looks similar to a handful of uncooked spaghetti, are included in every high school and college biology textbook. However, scientists were unable to explain how muscle contraction creates the forces that propel human movement.

Advance

Using advanced 3D imaging methods, IRP researchers led by Stadtman Investigator Brian Glancy, Ph.D., discovered that muscle cells are actually made up of a singular, highly branching contractile structure that connects across the entire length and width of the cell. The contiguous nature of this mesh-like 'myofibrillar matrix' thus permits the direct transmission of force throughout the entire connected network as it contracts.

Impact

This discovery overturns a long-held idea about the structure of muscle cells that is taught in general biology courses to scientists and non-scientists alike. In addition to providing a new view of how force is transmitted within muscle fibers to move our bodies, these findings could shed light on how muscles repair themselves after exercise and may have major implications for the many diseases that involve muscles, including heart failure, diabetes, muscular dystrophy, and age-related muscle loss.

Publications

Willingham TB, Kim Y, Lindberg E, Bleck CKE, Glancy B. (2020). The unified myofibrillar matrix for force generation in muscle. Nat Commun. July 24;11(1):3722. doi: 10.1038/s41467-020-17579-6.