ASSESSING THE MECHANISTIC TARGET OF RAPAMYCIN COMPLEX-1 PATHWAY IN RESPONSE TO RESISTANCE EXERCISE AND FEEDING IN HUMAN SKELETAL MUSCLE by MULTIPLEX ASSAY

ABSTRACT Background: The mechanistic target of rapamycin complex-1 (mTORC-1) is a key nutrient and contraction-sensitive protein that regulates a pathway leading to skeletal muscle growth. Utilizing a multiplex assay, we aimed to examine the phosphorylation status of key mTORC-1-related signalling molecules in response to protein feeding and resistance exercise. Methods: Eight healthy men (22.5 ± 3.1 yr, 80 ± 9 kg, 1-repetition maximum [1RM] leg extension: 87 ± 5 kg) performed 4 sets of unilateral leg extensions until volitional failure. Immediately following the final set, all participants consumed a protein-enriched beverage. A single skeletal muscle biopsy was obtained from the vastus lateralis before (Pre) with further bilateral biopsies at 1 h (1 h FEDEX and 1 h FED) and 3 h (3 h FEDEX and 3 h FED) post drink ingestion Results: Phosphorylated Akt Ser473 was significantly elevated from Pre at 1 h FEDEX. Phosphorylated p70S6K1 Thr412 was significantly increased above Pre at 1 h FEDEX and 1 h FED and was still significantly elevated at 3 h FEDEX but not 3 h FED. Phosphorylated rpS6 Ser235/236 was also significantly increased above Pre at 1 h FEDEX and 1 h FED with 1 h FEDEX greater than 1 h FED. Conclusion: Our data highlight the utility of a multiplex assay to assess anabolic signaling molecules in response to protein feeding and resistance exercise in humans. Importantly, these changes are comparable to those as previously reported using standard immunoblotting and protein activity assays.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author