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Carbohydrate-Induced Insulin Signaling Activates Focal Adhesion Kinase: A Nutrient and Mechanotransduction Crossroads
Nutrients (2020)
  • Dylan T. Wilburn, Baylor University
  • Steven B. Machek, Baylor University
  • Thomas D. Cardaci, Baylor University
  • Darryn S. Willoughby, University of Mary Hardin-Baylor
Abstract
Research has suggested that nutrient, exercise, and metabolism-related proteins interact to regulate mammalian target of rapamycin complex one (mTOR) post-exercise and their interactions needs clarification. In a double-blind, cross-over, repeated measures design, ten participants completed four sets to failure at 70% of 1-repitition maximum (1-RM) with 45 s rest on angled leg press with or without pre-exercise maltodextrin (2 g/kg) after a 3 h fast. Vastus lateralis biopsies were collected at baseline before supplementation and 1 h post-exercise to analyze Focal Adhesion Kinase (FAK), ribosomal protein S6 kinase beta-1 (p70S6K), insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), and 5′ AMP-activated protein kinase (AMPK) activation. FAK and IRS-1 activity were only elevated 1 h post-exercise with carbohydrate ingestion (p < 0.05). PI3K and p70S6K activation were both elevated after exercise in both conditions (p < 0.05). However, AMPK activity did not change from baseline in both conditions (p > 0.05). We conclude that FAK does not induce mTOR activation through PI3K crosstalk in response to exercise alone. In addition, FAK may not be regulated by AMPK catalytic activity, but this needs further research. Interestingly, carbohydrate-induced insulin signaling appears to activate FAK at the level of IRS-1 but did not enhance mTOR activity 1 h post-exercise greater than the placebo condition. Future research should investigate these interactions under different conditions and within different time frames to clearly understand the interactions between these signaling molecules.
Keywords
  • focal adhesion kinase,
  • insulin,
  • crosstalk,
  • mammalian target of rapamycin complex one (mTOR),
  • insulin receptor substrate 1 (IRS-1),
  • phosphatidylinositol 3-kinase (PI3K),
  • mechanotransduction
Disciplines
Publication Date
2020
DOI
10.3390/nu12103145
Citation Information
Dylan T. Wilburn, Steven B. Machek, Thomas D. Cardaci and Darryn S. Willoughby. "Carbohydrate-Induced Insulin Signaling Activates Focal Adhesion Kinase: A Nutrient and Mechanotransduction Crossroads" Nutrients Vol. 12 Iss. 10 (2020)
Available at: http://works.bepress.com/steven-machek/17/