immobilization of skeletal muscle increases mTORC1 signaling and LAT1 expression both at stretched and shortened positions but only increases protein synthesis at stretched position

2016 Fiscal Year Final Research Report

• Project/Area Number: 26350823
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Sports science
• Research Institution: Shigakkan University
• Principal Investigator: Murakami Taro 至学館大学, 健康科学部, 教授 (10252305)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: アミノ酸輸送体 / mTORC1 / SUnSET / ロイシン / ギプス固定

Outline of Final Research Achievements

We investigate whether a decrease in amino acid requirement in the muscle by immobilization with casting would inactivate the mammalian target of rapamycine complex 1 (mTORC1) signaling and decrease the leucine transporter (LAT1) expression. Both the mTORC1 signaling and the expression of LAT1 are activated in both immobilized muscles at shortened and stretched positions, even the extents are larger in the latter. However, muscle protein synthesis at fasted-state is only increased in a stretched muscle but not in a shortened muscle. Branched chain amino acids administration increases muscle protein synthesis in both shortened and stretched muscles.These findings suggest that the activation of mTORC1 signaling and induction of leucine transporter in the immobilized muscle at shortened position could not contribute to the protein synthesis. A decrease in atrophy in immobilized muscle at stretched position would due to be an increase in protein synthesis during preabsorptive state.

Free Research Field

運動栄養学