Fig. 8.

cFAM124A competes with CSTB through bait effect and enhances CTSL enzyme activity. A, MS of CSTB protein. B, CSTB was pulled down by the cFAM124A probe or LacZ probe (control). C, RIP assay showing the association of CSTB with cFAM124A. D-E, Co-IP assay of CSTB and CTSL in PDAC cells with cFAM124A overexpression or knockout. F, Predicted binding regions in cFAM124A for CSTB by CatRAPID. G, After PATU8988T cells were transfected with plasmids for wild-type or truncated cFAM124A overexpression, RNA pulldown assay was performed with cFAM124A-specific probes. H, Co-IP assay of CSTB and CTSL in PDAC cells in different treatment groups. I, Western blot analysis of CTSL, RXRα, Akt, p-Akt (Ser473), and p-Akt (Thr308) protein expression in the indicated groups. J, CTSL concentrations by ELISA in the indicated groups. K, Proposed mechanism by which cFAM124A promotes PDAC chemoresistance via “scaffolding” and “decoys-like” effects. Not significant (ns), *P < 0.05; **P < 0.01; ***P < 0.001