This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of the ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class. Alternative splicing of this gene generates 2 transcript variants diverging at the 3' end. [provided by RefSeq, Jul 2008].
Function: Substrate recognition component of the SCF (SKP1-CUL1-F-box protein)-type E3 ubiquitin ligase complex. Mediates the ubiquitination of HIPK2 and probably that of EP300, leading to rapid degradation by the proteasome. In the presence of PML, HIPK2 ubiquitination still occurs, but degradation is prevented. PML, HIPK2 and FBXO3 may act synergically to activate p53/TP53-dependent transactivation.