Moreover, circINSIG1 encodes a novel protein circINSIG1-121, which recruits CUL5-ASB6 complex to promote K48-linked ubiquitination of the critical cholesterol metabolism regulator INSIG1 at lysine 156 and 158, thereby facilitating cholesterol biosynthesis and CRC progression (Fig. 7H). This evidence concerns the gene CUL5 and colorectal carcinoma.