Mutagenesis experiments and functional studies suggest that phosphorylation of HSF1 residue Ser326 promotes induction of the HSF1 transcriptional competence in response to heat and other cell stressors including proteasome inhibitors and sodium arsenite (Guettouche T et al. 2005; Chou SD et al. 2012).
The mammalian target of rapamycin complex 1 (mTORC1) has been implicated in sensing intracellular protein misfolding (Qian SB et al. 2010; Chou SD et al. 2012). RNA interference?mediated repression of mTOR kinase activity in human HeLa cells was found to increase sensitivity to heat shock. Moreover, inhibition of HSF1 phosphorylation on Ser326 by rapamycin suggests that this site in HSF1 is a target for the mTORC1complex (Chou SD et al. 2012).