Putative ERAS in cultured human U2OS cells. (A) Consistent close association of the Tip20 homologue RINT1 with the ERES marker Sec16A. Immunofluorescence microscopy was used to visualize Sec16A together with RINT1, a subunit of the NRZ complex. The insets are magnified twofold relative to the original images. Scale bars, 5 µm. (B) Lack of consistent association of the Ufe1 homologue Syntaxin18 with the ERES marker Sec16A. Immunofluorescence microscopy was used to visualize Sec16A together with Syntaxin18, an ER-localized SNARE. Scale bar, 5 µm.