Component of some SCF (SKP1-cullin-F-box) protein ligase complex that plays a central role in G1 arrest following DNA damage. Specifically recognizes phosphorylated cyclin-D1 (CCND1), promoting its ubiquitination and degradation by the proteasome, resulting in G1 arrest (By similarity). Protein modification; protein ubiquitination. Part of a SCF (SKP1-cullin-F-box) protein ligase complex. Phosphorylation by ATM following gamma-irradiation results in its stabilization. Belongs to the FBXO31 family.