Figure 1: Temporal changes in co-chaperone binding to Hsp70 under stress conditions are correlated to Hsp70 acetylation.
From: ARD1-mediated Hsp70 acetylation balances stress-induced protein refolding and degradation
(a) After stress, Hsp70, but not Hsc70, gradually changes its co-chaperone complexes from protein refolding machinery (1–4 h) to degradation machinery (12–24 h). After treating HEK293T cells with 1 mM H2O2, endogenous Hsp70 and Hsc70 were precipitated, and their co-chaperone-binding partners were identified by western blotting (top). Quantification of relative co-chaperone bindings of Hsp70 and Hsc70 (bottom). The asterisk (*) indicates a background band. (b) Hsp70, but not Hsc70, is rapidly acetylated in response to stress. Endogenous Hsp70 and Hsc70 were precipitated from HEK293T cells treated with 1 mM H2O2, and their acetylation levels were assessed with an anti-Lys-Ac antibody. (c) Acetylation of Hsp70 occurs earlier than its transcriptional activation. SH-SY5Y cells stably expressing GFP-Hsp70 were treated with 1 mM H2O2, and the changes in GFP-Hsp70 acetylation and the expression of endogenous Hsp70 were compared. Error bars indicate s.d. (n=3). *P<0.05; **P<0.01; ***P<0.001 versus 0 h, t test.
