Assembly of signal recognition particles in the nucleolus

Abstract

In addition to its role in ribosome biogenesis, the nucleolus contributes to many other activities including the processing and assembly of other nonribosomal RNA-protein complexes. Recent findings suggest that the nucleolus is involved in the biogenesis of the signal recognition particle (SRP), a cytoplasmic ribonucleoprotein (RNP) complex that recognizes and targets select ribosomes to the endoplasmic reticulum membrane for the cotranslational translocation of membrane and secretory proteins. Assembly of the SRP into a functional RNP complex requires the ordered, sequential association of protein subunits onto the SRP RNA. Here, we will review our current understanding of SRP assembly with a focus on the role the nucleolus plays in SRP biogenesis. © 2011 Springer Science+Business Media, LLC.