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VOL. 76 (3), 357-377, 2010 TSC1-TSC2 COMPLEX ON THE CROSSROAD OF PANCREATIC...

in misfolded protein clearance (31). ß cells turned out to be more sen-
sible to apoptotic death mediated by chemical ER-stressors when com-
pared to fibroblasts (Figure 7A). Immunofluorescence assays showed
that both basal and rapamycin-induced autophagy is sensibly higher
in ß cells than the observed in fibroblasts, observed as the number of
LC3B puncta on cells (Figure 7C). Even more shocking are the differ-
ences between both cell types when stained with FK2 mAb against
ubiquitin-protein conjugates, which showed higher levels of protein ag-

Figure 6. Effect of mTORC1 inhibition or overactivation on ß cell prolifera-
tion. A) IR +/+ and IR -/- cells were counted and seeded at the same density, and
grown in glucose 1 g/L 10% FBS-DMEM. At 24 and 48 h, cells were counted. B) Same
experiment for Rec A and Rec B cells. Results are means ± S.E.M. *P < 0.05 com-
pared to control points. C) Transfected and control cells were grown in glucose 1 g/L
10% FBS-DMEM. DNA content was analyzed by flow cytometry. The bars represent
the percentual change of cells in S/G2-M phase compared to controls for each cell
line. D) Cells were seeded at the same density. After 24 and 48 h violet crystal stain
was measured as described. The differences between absorbances in 24 and 48 h, in
control or TSC2 downregulated cells, are represented. Results are means ± S.E.M. *P
< 0.05 compared to controls for each cell line.

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