It is shown that after activation, Ire1 molecules cluster into discrete foci containing high order oligomers on the endoplasmic reticulum membrane. HAC1 mRNA is recruited to these foci by means of a sequence in its 3′ UTR and is processes at these sites. Disruption of either Ire1 clustering or HAC1 mRNA recruitment impairs UPR signalling. Hence HAC1 mRNA is delivered to a site where it is processed thus ensuring that it is only translated when UPR is on.
- Tomás Aragón
- Eelco van Anken
- Peter Walter
