FIG. 3.

Nuclear sequestration of TTP induces β4GalT1 mRNA stabilization. (A) TNF-α-induced nuclear translocation of TTP is inhibited by inhibitors of IKK and PKCδ. HUVECs were grown in chamber slides, treated with inhibitors, and stimulated for 1 h with TNF-α as indicated. Subcellular localizaton of TTP was determined by immunofluorescence microscopy after staining with anti-TTP antibodies. Hoechst staining indicates the position of nuclei. (B) Inhibition of TTP nuclear export by LMB stabilizes β4GalT1 mRNA. HUVECs were treated with LMB, before the half-life of β4GalT1 mRNA was determined as described in the legend to Fig. 1B. The graphs (relative β4GalT1 mRNA expression versus time after addition of ActD) for the determination of the half-lives are available in Fig. S3 in the supplemental material.