Figure 7.

MT2 cleaves AcRIIA and Bmpr2 and decreases their full-length forms on cell surface. A and B, MT2 cleaves ActRIIA (A) and decreases the full-length ActRIIA on the cell surface (B). Co-transfection of HEK293 cells with pCMV6-ActRIIA and pEGFP-N1, pCMV6-MT2, or S762A-MT2, biotinylation of cell-surface proteins, and immunodetection were performed essentially the same as described in the legend to Fig. 6, B and C. ActRIIA was detected by using an anti-FLAG antibody. C and D, MT2 cleaves Bmpr2 (C) and decreases the full-length Bmpr2 on cell surface (D). Experiments were performed as described above for ActRIIA. Bmpr2 was detected by using an anti-FLAG antibody. Two MT2/Bmpr2 images with different exposure times were presented (C). E and F, MT2 does not cleave Zip14 (E) and does not decrease cell-surface Zip14 (F). The experiments were performed as described above for ActRIIA and Bmpr2. Zip14 was immunodetected by using an anti-FLAG antibody. All experiments were repeated at least three times (technical replicate = 1; independent biological replicates ≥3) with consistent results.