SUFU and cancer: Furthermore, targeted proteolysis of Sufu in the nucleus, mediated by Fbxl17 (F-box and leucine-rich repeat protein 17) through ubiquitylation, liberates Gli-1 from Sufu and restores proper Shh signal transduction, whereas depletion of Fbxl17 results in impaired Shh signaling and compromised cancer cell proliferation and medulloblastoma tumor growth [41].