Figure 3.

SLC39A9 Regulates the Receptor Expression

(A) SubAB sensitivity in KDELR2, JTB, and SLC39A9 KO cells and their revertant cells. HA-tagged SLC39A9 was used in SLC39A9 revertant cells. Cells were treated with SubAB at the indicated concentrations. Viability was estimated as described for Figure 1B and is expressed as mean percentages ± SD obtained from three independent experiments. The Bonferroni corrected t test was used for multiple comparisons. *p < 0.0083.

(B) BiP cleavage in KDELR2, JTB, and SLC39A9 KO cells. Cells were incubated with the indicated concentration of SubAB for 12 h. SubAB-induced BiP cleavage was determined as described for Figure 2B. Experiments were repeated three times with similar results (upper panel). Data are the mean percentages ± SD obtained from three independent experiments. The Bonferroni corrected t test was used for multiple comparisons. *p < 0.017.

(C) Surface binding of SubAB on KDELR2, JTB, and SLC39A9 KO cells. Cells were stained with (blue lines) or without (black lines) Alexa 488-labeled SubAB (Alexa 488-SubAB) and analyzed using FACS. Yellow-green lines in all panels indicate staining in parent cells. A magenta line indicates staining in cDNA-restored cells.

(D) Detection of SubAB-binding proteins in KDELR2, JTB, and SLC39A9 KO cells. In the left image, biotinylated cell surface proteins prepared from the indicated cells were immunoprecipitated and detected as described for Figure 2D. Data are representative of at least three separate experiments. In the right image, L1CAM proteins in whole lysates were detected with anti-L1CAM antibodies.

See also Figure S3.