Investigating the upstream signaling of Imh1 phosphorylation under ER stress in yeast

ABSTRACT: The accumulation of misfolded proteins in the endoplasmic reticulum (ER) induces the unfolded protein response (UPR), which acts through various mechanisms to reduce ER stress. We previously found ER stress induced by tunicamycin (TM) treatment promotes the activation of small GTPase Arl1 and thereby increasing the recruitment of downstream effector golgin Imh1 to the late-Golgi. However, the role of Imh1 under ER stress remains unknown. In this study, we found Imh1 is required for the recycling of two SNAREs, Snc1 and Tlg1, upon TM-induced ER stress and phosphorylation of Imh1 is required for this regulation. Since Ire1 is the sensor of UPR in yeast and we previous found that Ire1 is required for Arl1-Imh1 activation, we wonder whether Ire1 signaling is also responsible for the TM-induced phosphorylation of Imh1 and the subsequent SNARE transport. We compared the phosphorylation signal of Imh1 in WT with that in the absence of Ire1 and further performed SILAC method in a label swap replication. Collectively, this study illustrates the mechanism of how signaling under ER stress promotes Imh1 in cooperation with another tether factor in regulating the SNARE transport to alleviate ER stress in yeast cells.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Chia-Jung Yu  

LAB HEAD: Chia-Jung Yu

PROVIDER: PXD031563 | Pride | 2022-07-21

REPOSITORIES: Pride