Zn²⁺ induction of S100A10-depleted PR9 cells up-regulates cell surface expression of S100A10. S100A10-depleted PR9 cells were treated with ZnSO₄ for the indicated times. Cell lysates were prepared, and total levels of S100A10, annexin A2, and PML-RAR were examined by Western blotting with the use of actin as a loading control (A). S100A10 up-regulation was quantified by determining the ratio between S100A10 and actin (B). Flow cytometric analysis of cell surface S100A10 (C) and annexin A2 (D) in S100A10 shRNA-transduced PR9 cells before and after induction with ZnSO₄.