Author:
Farajzadeh Nastaran,Shahbabian Karen,Bouaziz Yani,Querido Emmanuelle,Chartrand Pascal
Abstract
Messenger RNA (mRNA) localization is an important mechanism controlling local protein synthesis. In budding yeast, asymmetric localization of transcripts such asASH1mRNA to the bud tip depends on the She2 RNA-binding protein. She2 assembles as a tetramer to bind RNA, but the regulation of this process as part of the mRNA locasome is still unclear. Here, we performed a phosphoproteomic analysis of She2 in vivo and identified new phosphosites, several of which are located at the dimerization or tetramerization interfaces of She2. Remarkably, phosphomimetic mutations at these residues disrupt the capacity of She2 to promote Ash1 asymmetric accumulation. A detailed analysis of one of these residues, T109, shows that a T109D mutation inhibits She2 oligomerization and its interaction with She3 and the importin-α Srp1. She2 proteins harboring the T109D mutation also display reduced expression. More importantly, this phosphomimetic mutation strongly impairs the capacity of She2 to bind RNA and disruptsASH1mRNA localization. These results demonstrate that the control of She2 oligomerization by phosphorylation constitutes an important regulatory step in the mRNA localization pathway.
Funder
Institute for Research on Immunology and Cancer
the Montreal Clinical Research Institute
Fonds de Recherche du Québec-Santé
Natural Sciences and Engineering Research Council of Canada
Publisher
Cold Spring Harbor Laboratory