[Seminar] The HSP90/R2TP chaperone: the co-translational determination of quaternary structures and beyond

Title: The HSP90/R2TP chaperone : the co-translational determination of quaternary structures and beyond

Speaker: Severine Boulon

From: Institute of Human Genetics da Montpellier University

Abstract: The HSP90/R2TP quaternary chaperone assembles key cellular macromolecular complexes, including the three nuclear RNA polymerases, several non-coding RNPs, and many other clients that remain to be identified. Our team studies the role of the HSP90/R2TP chaperone in ensuring the formation of assembly intermediate subcomplexes in a sequential and correct manner, leading to the mature and functional macromolecular complex. To investigate whether client assembly starts co-translationally, we analyzed RNAs associated to R2TP and found that it binds many partners co-translationally, suggesting that the assembly starts at the translational level. However, for pairs of subunits assembling together and bound co-translationally by R2TP, only a marginal proportion of their mRNAs is co-localized and co-translated. Instead, the HSP90 and R2TP chaperones induce the formation of condensates accumulating client mRNAs of different macromolecular complexes, suggesting that these condensates do not favor co-translational subunit assembly but favor instead co-translational interactions between chaperones and client subunits. This mechanism, called co-translational chaperone channeling (cha-cha), substitutes for the rarity of co-localized/co-translated mRNAs.

Note: Although the seminar will be held in the auditorium of the Biofarma iBET building, it is open to the entire ITQB NOVA community. Anyone interested in the seminar will need to go to the main entrance of the Biofarma building and talk to security.