CCNF is the substrate recognition component of an SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex. The SCF(CCNF) complex is an integral part of the ubiquitin proteasome system and mediates the ubiquitination and subsequent proteasomal degradation of target proteins involved in cell cycle progression and the maintenance of genome stability. In G2 phase it targets CP110 for degradation, acting as an inhibitor of centrosome reduplication. It also promotes degradation of the ribonucleotide reductase subunit RRM2, which maintains a balanced dNTP pool, and of CDC6, which suppresses DNA re-replication.

Cyclin F also contributes to the control of G1 progression and S phase entry. It is involved in the ubiquitination and degradation of CDH1, the substrate adapter of the anaphase-promoting complex (APC/C), and so acts as an antagonist of APC/C. It may play a role in the G2 checkpoint after DNA damage, possibly by promoting ubiquitination of MYBL2/BMYB. In UniProt, the protein localises to the nucleus, the perinuclear cytoplasm and the centrioles of the centrosome.

The CCNF gene encodes a member of the cyclin family, a group of regulators of cell cycle transitions that bind and activate cyclin-dependent protein kinases. It belongs to the Cyclin AB subfamily. It is also an F-box protein: the F-box is a motif of roughly 40 amino acids, and F-box proteins form one of the four subunits of SCF complexes, which function in phosphorylation-dependent ubiquitination. Cyclin F falls in the Fbxs class, which contains varied or no recognisable protein-protein interaction modules, and was one of the first proteins in which the F-box motif was identified. This history explains the aliases FBX1 and FBXO1. HGNC also lists the gene among microRNA protein coding host genes. Mouse and rat orthologs are both named Ccnf.