Protein SMG5 (SMG5)

Plays a role in nonsense-mediated mRNA decay. Doesn't have RNase activity by itself.

Promotes dephosphorylation of UPF1. Together with SMG7 is believed to give a link to the mRNA degradation machinery involving exonucleolytic pathways, and to function as an adapter for UPF1 to protein phosphatase 2A (PP2A), thereby triggering UPF1 dephosphorylation.