β-tranducin repeats containing protein (Beta-TrCP) is 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 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 Fbws class; in addition to an F-box, this protein contains multiple WD-40 repeats. The encoded protein mediates degradation of CD4 via its interaction with HIV-1 Vpu. It has also been shown to ubiquitinate phosphorylated NFKBIA, targeting it for degradation and thus activating nuclear factor kappa-B.
