The protein encoded by this gene is a type I transmembrane protein that localizes to the endocytic pathway. This protein contains a RING zinc-finger motif and has been shown to possess E3 ubiquitin ligase activity. Expression of this gene in retrovirally transduced T cell hybridoma significantly inhibits activation-induced IL2 and IL4 cytokine production. Induced expression of this gene was observed in anergic CD4(+) T cells, which suggested a role in the induction of anergic phenotype. Alternatively spliced transcript variants encoding distinct isoforms have been reported.