Open AccessEndurance exercise induces REDD 1 expression and transiently decreases mTORC 1 signaling in rat skeletal muscle
Author(s) -
Hayasaka Miki,
Tsunekawa Haruka,
Yoshinaga Mariko,
Murakami Taro
Publication year - 2014
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12254
Subject(s) - mtorc1 , p70 s6 kinase 1 , skeletal muscle , medicine , endocrinology , pi3k/akt/mtor pathway , endurance training , muscle contraction , adenosine triphosphate , phosphorylation , chemistry , signal transduction , biochemistry
Working muscle conserves adenosine triphosphate ( ATP ) for muscle contraction by attenuating protein synthesis through several different pathways. Regulated in development and DNA damage response 1 ( REDD 1) is one candidate protein that can itself attenuate muscle protein synthesis during muscle contraction. In this study, we investigated whether endurance exercise induces REDD 1 expression in association with decreased mammalian target of rapamycin ( mTOR ) complex I ( mTORC 1) signaling and global protein synthesis in rat skeletal muscle. After overnight fasting, rats ran on a treadmill at a speed of 28 m/min for 60 min, and were killed before and immediately, 1, 3, 6, 12, and 24 h after exercise. REDD 1 mRNA and corresponding protein levels increased rapidly immediately after exercise, and gradually decreased back to the basal level over a period of 6 h in the gastrocnemius muscle. Phosphorylation of mTOR Ser2448 and S6K1 Thr389 increased with the exercise, but diminished in 1–3 h into the recovery period after cessation of exercise. The rate of protein synthesis, as determined by the surface sensing of translation ( SU n SET ) method, was not altered by exercise in fasted muscle. These results suggest that REDD 1 attenuates exercise‐induced mTORC 1 signaling. This may be one mechanism responsible for blunting muscle protein synthesis during exercise and in the early postexercise recovery period.