Fig. 4

STC1 directly binds to ITGB6 to activate the PI3K signaling pathway, participating in lipid metabolism in vitro. A Cell extracts from Skov3-ip1 cells were immunopurified on STC1 affinity columns and eluted with the STC1 peptide. The eluates were resolved by SDS-PAGE and silver staining, and the results were confirmed by WB assays. B The interaction between STC1 and ITGB6 was confirmed by FRET-FLIM upon transient co-expression. C Co-IP analysis demonstrated an interaction between the STC1 and ITGB6 proteins in Skov3-ip1 and Hey cell lines. D Top 15 pathways identified by KEGG pathway enrichment analysis. E Representative WB results of proteins in the PI3K signaling pathway and integrin family in Skov3-ip1 and Hey cell lines. F IF analysis identified the co-localization of STC1 and ITGB6 in Skov3-ip1 and Hey cell lines. G PCA of data from untargeted relative quantitative lipidomic analysis. H Volcano plot of individual lipid species significantly up- or down- regulated in the NC group versus the ITGB6-sh1 and ITGB6-sh2 groups in Hey cell lines (lipids with a P value < 0.05 and a fold change (FC) > 1.5 or < 0.67 were indicated in blue or red, respectively). I Correlation analysis of the 5 lipid classes. J Representative WB results of ITGB6 and proteins in the PI3K signaling pathway in Skov3-ip1 and Hey cell lines. (Data are shown as the mean ± SD values. Significance was calculated using Student’s t test. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.)