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 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 Fbls class and, in addition to an F-box, contains 6 tandem leucine-rich repeats. The amino acid sequence of this protein is highly similar to that of f-box and leucine-rich repeat protein 3A. Comparisons of this gene to orthologous sequences suggest that it may be a pseudogene, and may no longer express a functional protein.[provided by RefSeq, Aug 2009]. Sequence Note: This RefSeq record retains a mismatch versus the reference genome sequence and available transcript data; translation of the genomic sequence results in a nonsense codon and truncation of the predicted protein. In addition, the transcript represents a splice pattern that uses AT-AG splice sites for the last intron, but it is not known if these splice site are functional in vivo.
Function: Substrate-recognition component of some SCF (SKP1-CUL1-F-box protein)-type E3 ubiquitin ligase complex involved in circadian pacemaker function. The SCF(FBXL21) complex acts by mediating ubiquitination and subsequent degradation of CRY1. Probable clock-controlled protein that plays a specific role in suprachiasmatic nucleus, SCN and pacemaker function (By similarity.