Intracellular distribution of ERESs using FP-tagged COPII expressed in living intact cells. (A) Intracellular distribution of ERESs. A confocal image of a COS7 cell coexpressing the ER marker VSVG-YFP (left and green in merged image) at the nonpermissive temperature 39.5°C or the ER membrane marker reticulon-GFP (left insert and green in merged insert) and the COPII subunit Sec24C-mCherry (center, and red in merged image). Scale bars = 5 µm. (B) A HeLa cell clone expressing an endogenous (endo) Sec13-mCherry (red) inserted using the CRISPR/CAS12 knock-in method were transfected with VSVG-EGFP (green). Cells were transferred to permissive temperature (32°C) after an overnight incubation at 39.5°C, and images were taken at 15-s intervals for ∼40 min. See Video 1. Shown are images at 0 and 40 min. Scale bars = 5 µm.