FIGURE 4.

Heparan sulfate-binding factors are required for shed syndecan-1 translocation to the nucleus. A, conditioned medium containing sSDC1 was incubated with heparin-agarose beads overnight to strip heparin-binding growth factors from the heparan sulfate chains of syndecan-1. An ELISA was performed to measure levels of HGF after heparin-agarose treatment to confirm that the heparin-agarose beads had removed heparin-binding proteins. B, conditioned medium was pretreated with heparin-agarose and incubated with ST2 cells for 2 h, and the level of sSDC1 in the nucleus was assessed by ELISA. To confirm that heparin-binding factors are required for translocation to the nucleus, purified sSDC1 was incubated with ST2 cells for 2 h, and the level of sSDC1 in the nucleus was assessed by ELISA. All data are mean ± S.E. of three independent experiments. *, p < 0.05 versus untreated controls.