The double life of ribosomal proteins

Abstract

Many integral proteins of the ribosome also carry out extra-ribosomal functions as independent polypeptides, raising questions as to their evolutionary derivation. In this issue of Cell, Mazumder et al. report a surprising new twist in the dual life of these molecules: as part of a cellular response to interferon, a large-subunit protein dramatically exits the ribosome to bind and inhibit the translation of a specific mRNA.