A zipcode unzipped.

RNA-binding proteins (RBPs) exert many roles in the post-transcriptional regulation of gene expression in eukaryotic cells. However, our understanding of how they recognize their target RNAs in vivo remains limited. In the January 1, 2012, issue of Genes & Development, Patel and colleagues (p. 43-53) provide detailed mechanistic insights into how one of the best-studied RBPs, zipcode-binding protein 1 (ZBP1), recognizes a bipartite RNA sequence element within the β-actin mRNA.