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. May act as a tumor suppressor. Protein modification; protein ubiquitination. Part of a SCF (SKP1-cullin-F-box) protein ligase complex. Highly expressed in brain. Expressed at moderate levels in most tissues, except bone marrow. Expression is cell-cycle regulated, and peaks at late G2 to early G1 phase (at protein level). By DNA damage. Increases after UV irradiation, X-ray irradiation, oxidative stress (H(2)O(2)) or addition of the chemotherapeutic DNA-damaging agents etoposide, adriamycin, cisplatin or fluorouracil. Phosphorylation at Ser-278 by ATM following gamma-irradiation results in its stabilization. The disease is caused by variants affecting the gene represented in this entry. Belongs to the FBXO31 family.