UneCLIPsing HuR nuclear function

Abstract

The RNA-binding protein HuR, while known to stabilize cytoplasmic mRNAs, is largely nuclear. In this issue of Molecular Cell, Mukherjee et al. (2011) and Lebedeva et al. (2011) identify transcriptome-wide HuR-RNA interactions using PAR-CLIP, unveiling HuR's nuclear role in pre-mRNA processing.

Figure 1. Flow of HuR influence on target gene expression

As uncovered by the studies of Mukherjee et al. (2011) and Lebedeva et al. (2011) in this issue of Molecular Cell, the influence of HuR upon target transcripts begins in the nucleus, where HuR associates with the pre-mRNA introns (thin black lines) and affects splicing and likely other nuclear processing events (although these functions are unconfirmed, as shown by the ‘?’). After assisting with export of the mature mRNA out of the nucleus, HuR’s impact continues in the cytoplasm, where it stabilizes mRNAs, may help with transient mRNA storage (as in stress granules), and modulates the recruitment of the mRNA with the translation machinery (polysomes).