To identify the form of PRDX1 that potentially interacts with CUL5 and UBE2F, we studied whether oligomerization of PRDX1 is required for CUL5 neddylation by treating CRC cells with Conoidin A (CoA, a PRDX1 inhibitor that covalently binds to the catalytic cysteine) to inhibit the oligomerization of PRDX1 (ref. 36,37). Here, CUL5 is linked to colorectal carcinoma.