Fig. 4: Thbs1 binds and activates a PERK-mediated ER stress response.
From: Thbs1 induces lethal cardiac atrophy through PERK-ATF4 regulated autophagy
a Representative western blots for ATF6α-N (50 kDa, nuclear), phospho-IRE1α (Ser 724; arrowhead), total IRE1α, phospho- and total PERK, phospho-eIF2α (Ser 51), total-eIF2α, ATF4, and DNAJC3. Phospho-PERK was analyzed using Phos-tag gels. The heart protein extracts are from the indicated mice at 4 weeks of age. Gapdh serves as a processing and loading control. b, c Western blot for Thbs1 and PERK following immunoprecipitation (IP) of PERK (b) or Thbs1 (c) from protein extracts of tTA cont. and Thbs1 DTG hearts at 6 weeks of age. IPs with corresponding IgG served as negative controls. Vinculin is an input loading control. d Schematic diagram of Thbs1 with the GST-Thbs1 fusion proteins regions shown (red bars). Below the schematic a representative western blot for PERK following GST pull-down with the different Thbs1 domains from primary neonatal rat ventricular cardiomyocyte extracts. GST protein serves as a negative control. e-i, Quantitative RT-PCR for Eif2ak3 (PERK protein; *P = 0.0317 vs tTA control), Atf4 (*P = 0.0006 vs tTA control), Atf3 (*P = 0.0058 vs tTA control), Ddit3 (Chop protein; *P < 0.0001 vs tTA control)) and Fgf21 (*P = 0.0023 vs tTA control) from mRNA isolated from hearts of tTA cont. (n = 6 biologically independent animals) and Thbs1 DTG mice (n = 5 biologically independent animals) at 6 weeks of age. Statistical analysis was performed using two-tailed Student’s t test. Error bars are ±standard error of the mean. Source data are provided as a Source Data File.
