2-5A-Dependent RNase L

This chapter provides a general overview of 2-5A-dependent RNase L. RNase L contains an array of structural and functional domains that are unique among known and sequenced ribonucleases. An intriguing feature of RNase L is the presence in the amino-terminal half of the enzyme of nine units of about 33 amino acids in length, each containing an ankyrin-related repeat sequence. Ankyrin repeats, named after the ankyrin family of proteins, mediate interactions between and within many different proteins. Ankyrins binds integral membrane proteins and tubulin through their N-terminal domains consisting of 22 such elements. The central domain of erythrocyte ankyrin, which lacks ankyrin repeats, binds to spectrins and vimentin. Therefore, in a single protein, ankyrin repeats may bind some proteins whereas other proteins may attach through additional interaction domains. This chapter discusses perspectives on the 2-5A system, and elaborates structure and functions of RNase L. Biochemical properties of RNase L are also discussed. The chapter explains distribution, localization, and regulation of RNase L and its gene. The chapter concludes with discussing the antiviral activity and antiproliferative effects of RNase L.