Fig 1: IRE1a controls migration via FLNA bond and activation. (A) Results of immunoprecipitation for IRE1a followed by WB analysis for FLNA and IRE1a itself in HD- and MM-BMMSCs both in non-migrating (NoM) and migrating conditions (Migr = FBS and PBM). After a 24 h transwell assay, BMMSCs were lysed and IRE1a immunoprecipitation was performed. IgG: ctrl with anti-IRE1a antibody without protein sample. (B) Relative quantification of the ratio between FLNA and IRE1a protein level in migrating (Migr = FBS and PBM) relative to non-migrating (NoM) condition. NoM, n = 5; Migr, n = 10. Two-tailed t-test; **, p < 0.01. (C) WB analysis of samples from BMMSCs in non-migrating (NoM) conditions and after 24 h of migration (Migr). A-MEM supplemented with 10% FBS was used as chemo-attractive agent. On the right, relative quantification of IRE1a level compared to NoM condition. n = 8. Two-tailed t-test, **, p < 0.01. (D) WB analysis in samples from BMMSCs after downregulation of IRE1a with Si-IRE1a for 72 h. Ctrl = only transfection agent. (E) WB analysis in BMMSCs after transfection with Si-IRE1a for 72 h and 24 h migration through 8 µm membrane; A-MEM supplemented with 10% FBS was used as chemo-attractive agent. On the right, relative quantification, with ImageJ, of P-FLNA level in Si-IRE1a samples compared to Ctrl. n = 9, one-tail t-test; **, p < 0.01. (F) Analysis of migration in HD- (left) or MM-BMMSCs (right) after downregulation of IRE1a with Si-IRE1a. BMMSCs were first transfected with Si-IRE1a for 72 h and then seeded on transwell membrane. A-MEM supplemented with 10% FBS was used as chemo-attractive agent. Relative migration to Ctrl cells was calculated. HD-BMMSCs: both Ctrl and Si-IRE1a n = 10; MM-BMMSCs: both Ctrl and Si-IRE1a n = 8. Two-tailed t-test; **, p < 0.01; ***, p < 0.001.