FBXO5

F-box only protein 5 is a protein that in humans is encoded by the FBXO5 gene.

Function
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. This protein is similar to xenopus early mitotic inhibitor-1 (Emi1), which is a mitotic regulator that interacts with Cdc20 and inhibits the anaphase promoting complex. Moreover, Emi1 also assembles a CRL1 complex that targets RAD51 for ubiquitin-mediated degradation.

Disease
Gene and protein expression of FBXO5/Emi1 are increased in many human cancers and increased expression has been shown to cause chromosome instability and cancer.

Interactions
FBXO5 has been shown to interact with:
 * CDC20,
 * FZR1,
 * SKP1A. and
 * RAD51.