Cell Res. 2014 Feb;24(2):233-46.

Donghui Wu, Denise Muhlrad, Matthew W Bowler, Shimin Jiang, Zhou Liu, Roy Parker, Haiwei Song*

Abstract

The  evolutionarily conserved Lsm1-7-Pat1 complex is the most critical  activator of mRNA decapping in eukaryotic cells and plays many roles in  normal decay, AU-rich element-mediated decay, and miRNA silencing, yet  how Pat1 interacts with the Lsm1-7 complex is unknown. Here, we show  that Lsm2 and Lsm3 bridge the interaction between the C-terminus of Pat1  (Pat1C) and the Lsm1-7 complex. The Lsm2-3-Pat1C complex and the  Lsm1-7-Pat1C complex stimulate decapping in vitro to a similar extent  and exhibit similar RNA-binding preference. The crystal structure of the  Lsm2-3-Pat1C complex shows that Pat1C binds to Lsm2-3 to form an  asymmetric complex with three Pat1C molecules surrounding a heptameric  ring formed by Lsm2-3. Structure-based mutagenesis revealed the  importance of Lsm2-3-Pat1C interactions in decapping activation in vivo.  Based on the structure of Lsm2-3-Pat1C, a model of Lsm1-7-Pat1 complex  is constructed and how RNA binds to this complex is discussed.

Text link：http://www.nature.com/cr/journal/v24/n2/full/cr2013152a.html