Abstract:Objective To investigate the mechanism and molecular structural basis of the tension-regulated interaction between ICAP1 and β1 integrin. Methods Based on the crystal structure data of the ICAP1/β1 integrin cytoplasmic tail complex (PDB ID: 4DX9), tensile molecular dynamics simulations were conducted to observe and analyze the effects of tension loading on β1 integrin on the structure and binding affinity of the ICAP1/β1 integrin complex. Results The tension modulated the dissociation of the ICAP1/β1 integrin complex bidirectionally by inducing local conformational variations at the binding interface. It initially increased and then decreased the binding affinity of β1 integrin for ICAP1. The threshold point occurred at 10 pN. The main tension-sensitive residue interactions were primarily located among ARG140-THR789, MET141-THR789, and ASP145-SER785. Conclusions As the tension applied to the cytoplasmic tail of β1 integrin increases, the conformational variations at the binding interface result in an initial enhancement followed by a reduction in the inhibitory effect of ICAP1 on β1 integrin activation. A tension threshold of 10 pN was observed. This indicated that force-induced integrin activation requires sufficient mechanical stimulus strength. This study has provided a new approach for the development of antibody drugs targeting β1 integrins.