FIGURE 4.

SPRED1 and -2 inhibit DYRK1A-mediated cell proliferation by suppressing p53 deacetylation. A, 293 cells were transfected with combination of FLAG-tagged SPRED1, SPRED2 and HA-tagged DYRK1A. 24 h post-transfection, the cells were treated with 5 μm etoposide, or both 5 μm etoposide and 100 nm harmine for 24 h. Cell viability of the treated cells was analyzed as described under “Experimental Procedures” (n = 3, p < 0.05). B, levels of acetylated p53, total p53, HA-DYRK1A, and FLAG-SPRED1 and -2 in the WCL mentioned in A were determined by Western analysis with the indicated antibodies. Asterisk indicates the quantification results of acetyl-p53. IB, immunoblot.