FIGURE 4.

HDAC2 activates protein synthesis of eIF4E-responsive target genes. A, overexpression of HDAC2 does not change total protein synthesis rate in HCT-116 cells. The protein synthesis rate was assessed by [³⁵S]methionine incorporation. VC, vector control. GAPDH, glyceraldehyde-3-phosphate dehydrogenase. B, overexpression of HDAC2 does not induce cytoplasmic mRNA level of ODC, survivin, and c-Myc in HCT-116 cells. C, forced expression of HDAC2 induces protein synthesis rates of ODC, survivin, and c-Myc in HCT-116 cells. ³⁵S-methioine-labled ODC, survivin, and c-Myc were detected by autoradiography. IP, immunoprecipitation; IB, immunoblotting. D, the effect of HDAC2 manipulation on 4E-BP1 phosphorylation and the formation of eIF4F complex in HCT-116 cells. The HCT-116 cells were transfected with HDAC2 or shRNA HDAC2 along with their individual control vector. 72 h after transfection, the cells were harvested, and the whole cell lysates were used for the immunoblotting and immunoprecipitation assays. Phosphorylation of 4E-BP1 at the threonines 37/46 or 70 was evaluated by immunoblotting using antibodies specifically recognizing phosphorylated (p) forms of 4E-BP1.