Cartoon image from

Cartoon image from

Physiologist Laurie Goodyear (Joslin Diabetes Center, Harvard Medical School, MA) and her colleagues recently published a study in the American Journal of Physiology that shows how overexpressing a protein can increase exercise capacity. The protein of interest was tribbles homolog 3 (TRB3), which is a mammalian form of the tribbles protein found in fruit flies (aka: Drosophila). Prior to this study, data suggested that TRB3 plays a role in metabolism so Dr. Goodyear’s team decided to examine this more closely in skeletal muscle, which is a major contributor to metabolism. What they discovered is that exercise increases the expression of the protein by 2.5 times in the triceps muscle of normal mice and that exercise capacity was significantly increased in mice that genetically overexpress the protein in their muscles. Moreover the muscles of the overexpressing mice were found to contain more oxidative, fatigue-resistant muscle fibers that would promote this enhanced exercise capacity.

I think I need more TRB3 in my muscles.


An D, Lessard SJ, Toyoda T, Lee M, Koh H, Qi L, Hirshman MF, Goodyear LJ. Overexpression of TRB3 in muscle alters muscle fiber types and improves exercise capacity in mice. American Journal of Physiology- Regulatory, Integrative and Comparative Physiology. 306: R925-R933, 2014.


  1. #1 Nigel
    August 4, 2014

    And insulin resistance alas

  2. #2 Kathleen Stewart
    Garrett Middle School Teacher
    August 14, 2014

    How do I get more TRB3 in my muscles