C-terminal domain of SNX1 plays critical role in the normal trafficking of mGluR1. A, B, Acute knockdown of endogenous SNX1 and replacement of endogenous SNX1 with SNX1ΔC, as shown by the Western blot (A) and quantitation of the Western blots (B). C, D, Representative images (C) and quantitation (D) showing no effect on the surface expression of myc-mGluR1 in shSNX1 and shSNX1:SNX1ΔC transfected primary hippocampal neurons. E, F, Representative images (E) and quantitation (F) suggested that knockdown of endogenous SNX1 resulted in the rapid recycling of myc-mGluR1 in 30 min post-ligand application, and replacement of endogenous SNX1 with SNX1ΔC failed to rescue the normal trafficking of the receptor. Results are presented as mean ± SEM collected from three independent experiments. Scale bar, 10 μm. ***p < 0.001, *p < 0.05; n.s., p > 0.05.