Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois.
Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.
Am J Physiol Cell Physiol. 2019 Oct 1;317(4):C629-C641. doi: 10.1152/ajpcell.00009.2019. Epub 2019 Jul 17.
The αβ-integrin is a transmembrane adhesion protein that connects laminin in the extracellular matrix (ECM) with actin in skeletal muscle fibers. The αβ-integrin is highly expressed in skeletal muscle and is concentrated at costameres and myotendious junctions, providing the opportunity to transmit longitudinal and lateral forces across the membrane. Studies have demonstrated that α-integrin subunit mRNA and protein are upregulated following eccentric contractions as a mechanism to reinforce load-bearing structures and resist injury with repeated bouts of exercise. It has been hypothesized for many years that the integrin can also promote protein turnover in a manner that can promote beneficial adaptations with resistance exercise training, including hypertrophy. This review provides basic information about integrin structure and activation and then explores its potential to serve as a critical mechanosensor and activator of muscle protein synthesis and growth. Overall, the hypothesis is proposed that the αβ-integrin can contribute to mechanical-load induced skeletal muscle growth via an mammalian target of rapamycin complex 1-independent mechanism.
αβ-整合素是一种跨膜黏附蛋白，将细胞外基质（ECM）中的层粘连蛋白与骨骼肌纤维中的肌动蛋白连接起来。αβ-整合素在骨骼肌中高度表达，集中在肌节和肌腱连接处，提供了在膜上传递纵向和横向力的机会。研究表明，α-整合素亚基 mRNA 和蛋白质在离心收缩后上调，作为一种增强承载结构并抵抗重复运动损伤的机制。多年来，人们一直假设整合素还可以通过促进有益适应的方式促进阻力运动训练中的蛋白质周转，包括肥大。本综述提供了整合素结构和激活的基本信息，然后探讨了其作为肌肉蛋白合成和生长的关键机械感受器和激活剂的潜力。总的来说，提出了这样一种假设，即αβ-整合素可以通过雷帕霉素复合物 1 非依赖性机制促进机械负荷诱导的骨骼肌生长。
