CACUL1 and breast cancer: In line with this, we provided evidence that NNMT/1‐MNA enhances the overall neddylation levels of the other three cullins proteins(cullin‐2,3,4), which are also well‐known substrates of UBC12.[32] These findings confirm NNMT/1‐MNA as a positive upstream regulator of the neddylation pathway in breast cancer.