Physical Society Colloquium

Biophysics of muscle contraction - from molecules to cells

Dilson Rassier

Department of Kinesiology and Physical Education
McGill University

The cellular and molecular mechanisms of muscle contraction are not clearly understood. They spread across several levels of cell organization, from the single molecular motor myosin II - responsible for motility at the nano-scale world - to myofibrils that make up a cell. We develop a series of studies to uncover the fundamental mechanisms of contraction at several levels of analysis. In order to achieve such challenging task, we developed techniques that allow molecular force and displacement measurements of a few piconewtons/nanometers during contractions produced in real time. The techniques are unique and provide a deep and fresh look into the mechanisms of contraction. While some results repeat what others have observed in larger scale studies (i.e. whole muscles), others are unexpectedly challenging and suggest that changes need to be made in the current theory of muscle contraction, developed ~50 years ago and still used with little contestation.