Overview
The RNA
recognition motif (RRM) is a highly conserved RNA-binding domain and is
present in one, two, or multiple copies in RNA-binding proteins.
The RRM consists of a 90 amino acid domain that contains two consensus
sequences termed ribonucleoprotein (RNP) domains. The first RNP is an eight
amino acid sequence (RNP1) centrally located in the 90 amino acid RRM,
while the second is a six amino acid sequence (RNP2) located at the
N-terminus of the RRM. Proteins with an RRM motif are abundant and found
mostly in eukaryotes. They are diverse in structure and function and are
involved in all post-transcriptional processes such as pre-mRNA processing,
splicing, RNA editing, mRNA export, translational regulation, and mRNA
stability and degradation. In recent years, the RRM has been shown to also
be involved in protein-protein interactions. Structural studies of RRM
domains and the complexes they form with RNA and proteins have given some
insight into the determinants of their binding specificity. Current
information on RRM-containing proteins reveals that the role of the RRM in
the cell may extend beyond a simple component of RNA recognition. Although
a multitude of proteins bearing an RRM motif have been identified, the
specific functions of many remain uncharacterized. Further biochemical and
structural studies are needed to understand the evolution and functional
diversity of RRM-containing proteins.
