Fig. 5.

UFMylation regulates ER homeostasis. (A) Xbp1 cleavage in unactivated and IFN-γ–activated ΔUfc1 and ΔUfc1-Ufc1^WT cells. (B) Immunofluorescence images (magnification: 60× 1.4 NA objective) of the ER protein PDI in ΔUfsp2/ΔUba5/ΔUfc1 cells and cells reconstituted with WT protein or functionally inactive mutant protein (MUT protein), Uba5 protein–protein interaction motif mutant (UFIM mutant). (C) Representative images using transmission electron microscopy (magnification: 3,000× direct magnification for overview images; 12,000× direct magnification for Inset) showing aberrant ER structures in ΔUba5 cells.