This review focuses on the role of changes in the contractile proteins actin and myosin in age-related deterioration of skeletal muscle function. Functional and structural changes in contractile proteins have been determined indirectly from specific force and unloaded shortening velocity of permeabilized muscle fibers, and were detected directly from site-directed spectroscopy in muscle fibers and from biochemical analysis of purified actin and myosin. Contractile proteins from aged and young muscle differ in (a) myosin and actomyosin ATPase activities, (b) structural states of myosin in contracting muscle, (c) the state of oxidative modifications. The extent of age-related physiological and molecular changes is dependent on the studied animal, the animal's age, and the type of muscle. Therefore, understanding the aging process requires systematic, multidisciplinary studies on physiological, biochemical, structural, and chemical changes in specific muscles.
Bibliographical noteFunding Information:
We thank Dawn Lowe, Deborah Ferrington, and Daniel Spakowicz for many useful discussions. This work was supported by NIH Grants to DDT (AR27906 and AG26160) and LT (AG17768 and AG21626).
- Aged muscle
- Enzymatic activity
- Oxidative modifications