The RNA recognition motif, a plastic RNA-binding platform to regulate post-transcriptional gene expression

ABSTRACT

The RNA recognition motif (RRM), also known as RNA-binding domain (RBD) or ribonucleoprotein domain (RNP) is one of the most abundant protein domains in eukaryotes. Based on the comparison of more than 40 structures including 15 complexes (RRM–RNA or RRM–protein), we reviewed the structure–function relationships of this domain. We identified and classified the different structural elements of the RRM that are important for binding a multitude of RNA sequences and proteins. Common structural aspects were extracted that allowed us to define a structural leitmotif of the RRM–nucleic acid interface with its variations. Outside of the two conserved RNP motifs that lie in the center of the RRM β-sheet, the two external β-strands, the loops, the C- and N-termini, or even a second RRM domain allow high RNA-binding affinity and specific recognition. Protein–RRM interactions that have been found in several structures reinforce the notion of an extreme structural versatility of this domain supporting the numerous biological functions of the RRM-containing proteins.