Anti-Flag antibody was added to the lysate of HUVECs transfected with Flag-FGF13 for co-immunoprecipitation, and IgG was used as a negative control. LC-MS/MS analysis was carried out by PTM Bio Co., Ltd (Zhejiang, China). The substrate proteins that may bind to FGF13 were screened out according to the score and Flag/IgG ratio of the detected proteins in the mass spectrometry data.