Figure 7.

Zinc enhances CREB phosphorylation via inhibiting CN activity. Phosphorylation of indicated proteins in the TCR signaling pathway was measured by Luminex phosphoprotein detection (A and C). T cells were activated for 48 h after an initial 2-h incubation with the indicated concentrations of zinc (A) or CN inhibitor FK506 (C). Representative data from three independent experiments are expressed as relative to control and normalized by total input protein in the cell lysate. Values shown are means ± sd (n=3); P < 0.001 compared with nonactivated cells, indicated by a–c. p, Phospho. (B) Representative data from three independent experiments for cellular CN activity assays are shown. Activity of CN was determined spectrophotometrically based on phosphate release from the substrate. Cell cytosol was obtained from lysates by ultracentrifugation and used for detection of cellular CN activity. Lysate was incubated with the indicated concentration of zinc or CN inhibitor FK506 for 10 min prior to addition of substrate. Values shown are means ± sd (n=3); Bars with different superscripts indicate the means are statistically different (P < 0.01–0.001).