Fig. 5: Fibulin2 interacts with Notch2 and inactivates the Notch2 signaling pathway.

a A bioinformatics analysis-based prediction suggested that Fibulin2 may interact with Notch2. b Double-labeling immunofluorescence staining revealed that Fibulin2 colocalized with Notch2 in BMSCs. The area with a dotted line is magnified and shown on the right. c–e Expression of Notch2 pathway genes. (*the Fibulin2 group vs. the control group, P < 0.05 on Day 5; #the Fibulin2 group vs. the control group, P < 0.05 on Day 10; n = 3). f WB was performed to detect N2ICD and Hes1 expression levels. g, h Quantification by WB. (*the Fibulin2 group vs. the control group, P < 0.05 on Day 5; #the Fibulin2 group vs. the control group, P < 0.05 on Day 10; n = 3). i, j Coimmunoprecipitation of Fibulin2 and Notch2. BMSCs were transfected with lentivirus expressing 3×Flag-tagged Fibulin2. i Cell lysates were immunoprecipitated with anti-3×Flag antibody or control IgG. The immunoprecipitates were immunoblotted with anti-Notch2 antibody. j Cell lysates were immunoprecipitated with anti-Notch2 antibody or control IgG. The immunoprecipitates were immunoblotted with anti-3×Flag antibody. k BLI-based biosensor technology was applied to demonstrate that Fibulin2 (Ala28–Leu1184) bound to Notch2 (Leu26–Gln530). The blue curves represent the true association and dissociation signals. The red curves show the curve fitting results. KD = 1.22 × 10⁻⁹ ± 3.16 × 10⁻¹¹.