Effects of energy stress on protein synthesis pathways in CT-2A and astrocytes. a) Influence of energy stress on mTOR activity. Cells were treated with 50 mM 2-DG for 0–30 minutes in serum free media. Cell lysates were probed with phosphorylated antibodies for mTOR and its substrate S6 kinase. b) Dephosphorylation of mTOR and S6 kinase in astrocytes was evident under energy stress condition whereas uncontrolled mTOR activity and delayed S6 kinase dephosphorylation was observed in CT-2A cells. c) Influence of rapamycin on low – glucose induced cell-death. CT-2A cells were cultured in 3.0 mM glucose containing medium with or without 50 nM rapamycin for 24 hours. Pictures were taken at 24 hours in cell culture. Note that the rapamycin treated CT-2A cells had much less floating cells than non-treated cells. Both floating and attaching cells were harvested and lysed for western blot assay for caspase – 3. Caspase-3 cleavage was noticed in CT-2A cells in low glucose condition which was prevented by rapamycin (d).