The balance of integrin activation and deactivation regulates its function and mediates cell behaviors. Mechanical force triggers the unbending and activation of integrin. However, how an activated and extended integrin spontaneously bends back is unclear. I performed all-atom molecular dynamics simulations on an integrin or its subunits to reveal the bending-unbending mechanism of integrin. According to the simulations, the integrin structure works like a human arm. The integrin α subunit serves as the bones, while the β leg serves as the bicep. The integrin extension results in the stretching of the β leg, and the extended integrin spontaneously bends as a consequence of the contraction of the β leg. This study provides new insights into the mechanism of how the integrin secures in the bent inactivated state and sheds light on how the integrin could achieve a stable extended state.

整合素激活和失活的平衡调节其功能并介导细胞行为。机械力触发整合素的伸直和激活。然而，激活和延伸的整合素如何自发地向后弯曲尚不清楚。我对整合素或其亚基进行了全原子分子动力学模拟，以揭示整合素的弯曲-不弯曲机制。根据模拟，整合素结构的工作原理就像人的手臂一样。整合素α亚基充当骨骼，而β腿充当二头肌。整合素延伸导致β腿拉伸，并且延伸的整合素由于β腿收缩而自发弯曲。这项研究为整合素如何确保弯曲失活状态的机制提供了新的见解，并揭示了整合素如何实现稳定的延伸状态。