P-selectin glycoprotein ligand 1 (PSGL-1) engaged by ezrin-radixin-moesin (ERM) proteins plays an important role in recruiting spleen tyrosine kinase (Syk) and activating leukocyte in the process of inflammatory re- sponse.Firstly,the crystal structure of radixin FERM domain indicates that the steric effect on ITAM-like motif and phosphorylation sites (Y191 and Y205) can hamper their phosphorylation by Src family tyrosine kinase and their combination with Syk.Then,steered molecular dynamics (SMD) simulation is carried out to explore the interaction between the complex of PSGL-1 juxtamembrane peptide and radixin FERM domain under force load.Both conforma- tion analysis and solvent accessible surface variant show that the mechanical signal transmitting through PSGL-1 cy- toplasmic region can mediate the exposition of phosphotyrosine site Y205 on ITAM-like motif of radixin.The results of this study present a mechanical signal pathway from PSGL-1 cytoplasmic region to Syk and expound the interac- tion mechanism of PSGL-1/ERM/Syk at atomic level.