InterPro domain: IPR013283

This entry represents the ABCE family of ATP-binding cassette (ABC) transporters and solely comprises of the ABCE1 gene product (also known as RNase L inhibitor, RLI1) [ 1 , 2 , 3 ]. RLI1 contains 2 nucleotide-binding domains (NBDs) typical of the ABC transporter protein superfamily [ 4 ]; however, it lacks the transmembrane domains required for membrane transport functions [ 4 , 4 ]. RLI1 was first identified as an endoribonuclease inhibitor that interacts directly with RNase L to prevent it from binding 2-5A (5'-phosphorylated 2',5'-linked oligo- adenylates) [ 4 ]. RNase L plays a major role in the anti-viral and anti-proliferative activities of interferons, and its inhibition by RLI1 occurs in a concentration-dependent manner [ 4 , 4 ]. Recently, RLI1 has been shown to be essential for the assembly of immature HIV-1 capsids in insect cells and higher eukaryotic cell types [ 5 ]. RLI1 expression is induced during HIV type I infection, and is understood to bind HIV-1 Gag (p55) polypeptides following their translation, and to promote their assembly into immature HIV-1 capsids [ 5 , 5 , 5 ].

1. Cloning and characterization of a RNAse L inhibitor. A new component of the interferon-regulated 2-5A pathway. J. Biol. Chem. 270, 13308-17
2. The human ATP-binding cassette (ABC) transporter superfamily. Genome Res. 11, 1156-66
3. Identification of a host protein essential for assembly of immature HIV-1 capsids. Nature 415, 88-92
4. cDNA cloning and expression analysis of the murine ribonuclease L inhibitor. Gene 209, 149-56
5. RNase L inhibitor is induced during human immunodeficiency virus type 1 infection and down regulates the 2-5A/RNase L pathway in human T cells. J. Virol. 73, 290-6