Protein synthesis is a key regulated cellular process that links nutrient 
availability and organismal growth. It has long been known that some cellular 
proteins continue to be synthesized under conditions where global translation is 
severely compromised. One prominent example is the selective translation of heat 
shock proteins (Hsps) under stress conditions. Although the transcriptional 
regulation of Hsp genes has been well established, neither the specific 
translation-promoting features nor the regulatory mechanism of the translation 
machinery have been clearly defined. Here we show that the stress-induced 
preferential translation of Hsp70 mRNA is negatively regulated by PI3K-mTORC1 
signaling. Despite the transcriptional up-regulation, the translation of Hsp70 
mRNA is deficient in cells lacking tuberous sclerosis complex 2. Conversely, 
Hsp70 synthesis is enhanced under the reduced PI3K-mTORC1 signaling. We found 
that the 5' UTR of Hsp70 mRNA contributes to cap-independent translation without 
exhibiting typical features of internal ribosome entry site. Our findings imply 
a plausible mechanism for how persistent PI3K-mTORC1 signaling favors the 
development of age-related pathologies by attenuating stress resistance.