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. 2019 Mar 28;2(2):e201800257. doi: 10.26508/lsa.201800257

Figure S14. PI3K and p38 control mTORC1 in a hierarchical manner in several cell lines.

Figure S14.

(A) When PI3K activity declines, p38 drives 4E-BP1-pT37/46 in MCF-7 cells. MCF-7 cells were serum-starved and treated with arsenite for 60 min upon wortmannin (100 nM, PI3K inhibitor) and/or LY2228820 (1 mM, p38 inhibitor). Data represent five biological replicates. (B) Comparison of the expression of mTORC1 targets. MCF-7, CAL51, LN18, HEK293T, and HeLa cells were serum-starved. p70-S6K and 4E-BP1 were monitored by immunoblot. Data represent three to four biological replicates. (C) Quantification of data shown in (B). p70-S6K and 4E-BP1 levels were compared between cell lines using a two-tailed t test across three to four biological replicates. Data represent the mean ± SEM. (D) When PI3K activity declines, p38 drives 4E-BP1-pT37/46 in CAL51 cells. MCF-7 and CAL51 cells were serum-starved and treated with arsenite for 60 min. For CAL51, the treatment was combined with wortmannin (100 nM, PI3K inhibitor) and/or LY2228820 (1 mM, p38 inhibitor). Data represent four biological replicates. (E) When PI3K activity declines, p38 drives 4E-BP1-pT37/46 in LN18 cells. MCF-7 and LN18 cells were treated as described in (D). Data represent four biological replicates. (F) When PI3K activity declines, p38 drives 4E-BP1-pT37/46 in HEK293T cells. MCF-7 and HEK293T cells were treated as described in (D). Data represent three biological replicates. (G) p38 drives 4E-BP1-pT37/46 in HeLa cells. MCF-7 and HeLa cells were serum-starved and exposed to arsenite for 60 min. For HeLa, the treatment was combined with wortmannin (100 nM, PI3K inhibitor) or LY2228820 (1 mM, p38 inhibitor). Note that in HeLa cells, Akt-pT308 is not arsenite inducible, indicative of low PI3K activity. Data represent three biological replicates.