Fig. 6.

cTAGE5 cKO disturbs the interaction between SEC23 and SAR1. (A) Tissue lysates of P20 WT and cKO mouse cortex were immunoprecipitated with SAR1-GTP antibody and probed with SEC23, cTAGE5, and SAR1-GTP antibodies. The relative levels of interaction between SAR1-GTP and SEC23 was defined as the level of SEC23 in the immunocomplex, normalized with the level of SEC23 in the input and SAR1-GTP in immunocomplex. Paired t test; **P < 0.01. n = 3. (B and C) Representative images of primary neurons at 14 div, which were dissected from around E15.5 WT and cKO mouse brains and stained with SAR1-GTP (B) or SAR1 (C) and SEC23 antibodies. (Right) Quantification of SAR1-GTP (B) or SAR1 (C) colocalized with SEC23. The “Surface” function of Imaris software was used to simulate the distribution of SEC23 (white SEC23′), and the portion of SAR1-GTP or SAR1 localized on the SEC23 surface was determined as colocalized with SEC23. t test; ***P < 0.001. Indicated number of neurons from five (for SAR1-GTP) and four (for SAR1) WT and cKO mice were analyzed. (Scale bars, 2 μm.)