Fig. 4

Mathematical model recapitulates HSR and NF-κB interaction via IKK signalosome. a Schematic representation of HSF1 signalling system. Red arrows indicate HS dependent regulation. b Schematic diagram of the proposed NF-κB and HS pathway crosstalk. Red arrows represent proposed temperature-dependent protein denaturation, green arrows represent events that involve interactions with HSP proteins. c Model simulations of the NF-κB-HSR crosstalk: wild type and HSF1 knock-down cells (KD HSF1) treated with TNFα (top) and IL1β (bottom) after different recovery times from HS (as indicated). Shown are the iterations of time-courses of nuclear NF-κB levels (100 representative iterations; coloured lines) and average nuclear NF-κB levels (in black), calculated from 1000 single cell model simulations (in number of molecules). Cells simulated for up to 10 h from the beginning of cytokine stimulation. d Kinetics of the IKK signalosome. Simulations were performed for 1 h HS at 43 °C followed by 10 h (IKK and cytokine-specific IKKK) or 20 h (HSPi) recovery time. Shown are time courses of simulated IKK, IKKK and HSPi levels in wild type cells (top) or cells with the HSF1 knock-down (KD HSF1) in number of molecules post HS. e Western blot analysis of soluble (S) and insoluble (IS) IKKα and IKKβ proteins level in MCF7 cells, either cultured under normal conditions (C) or subjected to 1 h HS at 43 °C and/or recovered for 1–4 h. β-actin was used as a loading control. The graph below shows the percentage of soluble and insoluble (S + IS = 100% in each experimental point) IKKs calculated based on Western blot densitometry