Tex2 is a tubular ER protein. (A) Representative images of a live COS7 cell expressing exogenous GFP-Tex2 (green) and ER-tagRFP (magenta, an ER luminal marker) with insets. (B) Representative images of a live GFP-Tex2-KI HeLa cell expressing endogenous GFP-Tex2 (green) and ER-tagRFP (magenta) with insets. (C) Domain organization of Tex2. (D–H) Representative images of COS7 cells expressing either GFP-Tex2-1-517 (green; D), GFP-Tex2-TM (green; residues 474–517; E), GFP-Tex2-∆1-473 (green; F), GFP-Tex2-(277-517) (green; G), or GFP-Tex2-∆277-473 (green; H), along with ER-tagRFP (magenta) with insets. (I) Pearson’s correlation coefficient of Tex2 proteins vs. ER-tagRFP; GFP-Tex2-TM (22 cells); GFP-Tex2-1-517 (19 cells); GFP-Tex2-∆1-473 (23 cells); GFP-Tex2-(277-517) (26 cells); and GFP-Tex2-∆277-473 (21 cells) in more than three independent experiments. Ordinary one-way ANOVA with Tukey’s multiple comparisons test. Mean ± SD. Scale bar, 10 μm in the whole cell images and 2 μm in the insets in A, B, and D–H.