Figure 3 | Cell Death & Disease

Figure 3

From: TGF-β induces TIAF1 self-aggregation via type II receptor-independent signaling that leads to generation of amyloid β plaques in Alzheimer's disease

Figure 3

Smad4 regulates TIAF1 self-binding and cell fate. (a) TGF-β1 (5 ng/ml) induced self-aggregation of TIAF1 (see green punctate formation), which leads to apoptosis of NCI-H1299 cells overexpressing EYFP-TIAF1, as determined by time-lapse microscopy. Also, see Supplementary Video 1. (b) Cell lines, including neuroblastoma SK-N-SH and SH-SY5Y cells, normal lung epithelial Mv1Lu cells, and lung cancer NCI-H1299 cells, were transfected with ECFP-TIAF1 and EYFP-TIAF1 by electroporation and then cultured for 24 h. These cells underwent apoptosis significantly, compared with cells overexpressing ECFP and EYFP (measured at the SubG0/G1 phase; P<0.0005, n=3, Student's t test). Cont, control (no electroporation). Sham, electroporated with medium only. C/Y, ECFP and EYFP; T/T, ECFP-TIAF1 and EYFP-TIAF1. (c) When ECFP-Smad4 was expressed at a greater level than EYFP-TIAF1 in NCI-H1299 cells, TGF-β1 (5 ng/ml) rapidly increased the binding of Smad4 with TIAF1 in 20 min (red color line for FRETc), and concurrently cell death occurred (reduction in cell size). (d) In contrast, cells became refractory to TGF-β1-mediated apoptosis, when the expressed EYFP-TIAF1 level was higher than ECFP-Smad4. Under this condition, the binding affinity of these proteins was reduced

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