Possible role in ribosomal RNA processing. May function as a substrate receptor for CUL4-DDB1 E3 ubiquitin-protein ligase complex (By similarity). Protein modification; protein ubiquitination. In the nucleolus, localizes predominantly in the granular component, but also detected in the fibrillar center and dense fibrillar component. Belongs to the WD repeat DCAF13/WDSOF1 family.