PRKCSH and neoplasm: Although in present study we have not determined how other components of the UPRosome contribute to the association or disassociation of the PRKCSH–IRE1α complex, our results suggest that the endogenous level of PRKCSH in each cell type determines the extent of its interaction with IRE1α and the activity of IRE1α, which is important for adaptation of tumor cells to ER stress.