Endostatin-treatment induces signal transduction in IBE cells.

IBE cells were incubated with (+) or without (−) FGF-2 and endostatin for 10 minutes (A, C) or 24 hours (B). The lower panels in (A) and (B) represent longer exposures of the immunoblot shown in the top panel. In (C), R522KShb-IBE cells were stimulated with endostatin and/or FGF-2. Cells were lysed and immunoprecipitated (IP) using antiserum against Shb, followed by SDS-PAGE and immunoblotting using the antiphosphotyrosine antibodies 4G10 or the anti-Shb antiserum, as indicated. The ratios of densitometric recordings of Shb and tyrosine phosphorylated Shb are provided in the figure, because the total amounts of Shb varied slightly between the different lanes in the (B) and (C) panels. Molecular masses of marker proteins run in parallel and the migration of Shb are indicated to the right in the panels.