Wild-type but not sorting-defective TGBp3 forms puncta at highly curved ER tubules in N. benthamiana. (A) Protoplasts of N. benthamiana expressing the wild-type or I33A form of GFP-TGBp3 were imaged by confocal microscopy at 8 h after transformation. The center and peripheral sections are shown. (B) Same as A, except that leaf epidermal cells of N. benthamiana were imaged at 6 h after transformation. (C) N. benthamiana epidermal cells expressing various TGBp3 and ER markers (AtRTNLB13, the ER tubule marker; AtSec61γ, the ER sheet marker) were imaged by confocal microscopy. Bars, 10 µm.