Figure 4.

Decrease in phosphorylation of GSK-3 after Sema 3A treatment in MDA-MB-231 breast carcinoma cell lines. Western blots of MDA-MB 231 cell extracts using anti–P-(Ser9)-GSK-3β, anti–GSK-3β, and antiactin antibodies. Cell lysates were prepared from PBS-treated control and Sema 3A–Fc–treated (1 μg/ml for 1 h) MDA-MB 231 cells in the presence or absence of LiCl (at 20 mM). All experiments were performed in duplicates. Sema 3A treatment notably decreases Ser9 phosphorylation of GSK-3. Treatment with the GSK-3 inhibitor LiCl enhances GSK-3 phosphorylation slightly and antagonizes the Sema 3A–mediated decrease in Ser9 phosphorylation. Blots were reprobed with an anti–GSK-3β antibody to confirm equal loading of samples.