In human cells, in high-iron condition, two iron atoms stabilise the F-Box FBXL5 and then the complex mediates the ubiquitination of IRP2.
This protein is a target for SMAD-specific E3 ubiquitin ligases, such as SMURF1 and SMURF2, and undergoes ubiquitination and proteasome-mediated degradation.
Vpu interacts with tethrin by interacting with the protein at its transmembrane domain and recruiting β-TrCP2, which causes ubiquitination and degradation of tetherin.