MPII is not efficiently internalized by the cells.

<p><b>A</b>, HT29 cells were left intact or incubated for 3 h at 18°C or 37°C with b-MPII-E352A (10 µg/ml). B, HT29 cells were incubated for 3 h at 37°C with b-MPII (10 µg/ml). In A and B, where indicated, MESNA or GM6001 (25 µM) was added to the cells. Cell lysates were analyzed by Western blotting with ExtrAvidin-HRP or the Hisx6-tag antibody.