G1P3 Background Information G1P3, also known as Interferon alpha-inducible protein 6 (IFI6) and Interferon-induced protein 6-16, is a 130 amino acid member of the IFI6 family of proteins. Localized to the mitochondria, G1P3 is a multi-pass membrane protein that is induced by IFN-α2∫. G1P3 has been shown to play a major role in the apoptosis pathway. Specifically, G1P3 acts as a cell survival protein by inhibiting caspase-3 activity, which antagonizes apoptosis. G1P3 has been implicated in tumorigenesis and is the subject of therapeutic studies, as reducing G1P3-mediated antiapoptotic signals could suggest improved therapies for myeloma or other malignancies.