FIGURE 7.

MEK/ERK inhibition on mTORC1 is TSC2-dependent, but its inhibition on mTORC2 is TSC2-independent. A, depleting TSC2 increased mTOR activity and crippled Beclin 1 up-regulation and LC3 processing by MEK/ERK activation. H4IIE cells stably transfected with constitutively active (ca) MEK or ERK were transiently transfected with siRNA against TSC2. B, depleting TSC2 did not affect MEK/ERK activation but crippled Beclin 1 up-regulation and LC3 processing in response to autophagy stimuli. H4IIE cells were transfected with siRNA against TSC2 and starved for amino acids (AA). C, depleting TSC2 crippled the disassembly of mTORC1 but not mTORC2 in response to autophagy stimuli. H4IIE cells were transfected with siRNA against TSC2 and starved for amino acids, and mTOR binding to Raptor, Rictor, or GβL was determined. The binding was quantified by density scanning. Shown in this figure from A to C are the representative Western blots (WB) or co-immunoprecipitate (IP) blots or quantified data (means ± S.D.) of each of three independent experiments. Ctrl, control; p-, phospho-.