Figure 4.

mTORC1 promotes EGF-dependent cytoskeletal reorganization and migration of spinal cord astrocytes. A, EGF induces morphological changes in astrocytes. Astrocytes treated with rapamycin were stimulated for 15 min with EGF, fixed, and stained for paxillin (green), F-actin (red), and DNA (blue). Scale bar, 20 μm. B, Rapamycin inhibits astrocyte chemotactic migration toward EGF. Astrocytes were seeded on Transwell filters coated with laminin and allowed to migrate through the filters toward EGF for 4 h. The histogram shows the average number of cells that migrated to the lower side of the filters in the different conditions relative to control. Error bars indicate the SE from three independent experiments, each with triplicate samples. C, Lysates from astrocytes treated for 4 h with rapamycin and untreated controls were probed by immunoblotting with antibodies to phosphorylated Akt (p-Akt) and phosphorylated S6 kinase (p-S6 kinase) and reprobed with antibodies to Akt and S6 kinase.