Molecular chaperones act as sentries within the cell to detect and refold proteins that have become misfolded. When cells are stressed, existing proteins can misfold, constituting a 'proteotoxic' stress that induces upregulation of the chaperones necessary to refold them. Another cellular stress response is the global downregulation of protein translation, previously thought to occur predominantly by inhibition of the initiation stage, which is when most regulation occurs. However, two recent studies, by Qian and colleagues and by Burge and colleagues, show that the ribosome is also controlled at the elongation phase during proteotoxic stress. The authors observed that in stressed cells, most ribosomes undergo extensive but transient pausing at an early stage in elongation, within the first 50–65 codons. This is coincident with a shift in profile from heavy polysomes to lighter polysomes or monosomes. Because the ribosome occludes ∼30–40 amino acids of the nascent polypeptide chain, the site of pausing suggested that accumulated misfolded proteins could be titrating out ribosome-associated chaperones that lie near the peptide-exit tunnel, such as Hsp70, and that this titration inhibited translation. By various means, this model was confirmed. The mRNAs that show translational pausing encode polypeptides with hydrophobic N termini, which are preferred ligands for Hsp70, and the polysomes on those transcripts were associated with 2- to 4-fold less Hsp70. Treatment with an Hsp70 inhibitor led to accumulation of ribosomes at 5′ ends even in the absence of stress. Conversely, moderate overexpression of Hsp70 could alleviate some ribosomal pausing under stress conditions. Heat shock also reduced the association of ribosomal proteins that sit near the exit tunnel (RPL23A) with Hsp70. Supplementation with recombinant chaperones in an in vitro translation system (derived from stressed cells) could reactivate translation. By suppressing translation at both the initiation and elongation levels, the amount of cellular proteins that require refolding by chaperones is reduced. Although these studies indicate that the level of Hsp70 available for cotranslational association with nascent chains dictates elongation, it is still unclear mechanistically how the absence of chaperones brings translation to a halt. Burge and colleagues suggest that the chaperones regulate the structure of the exit tunnel and note also that lower levels of chaperones at the exit tunnel during cellular stress may result in misfolding of N-terminal hydrophobic patches. (Mol. Cell doi:10.1016/j.molcel.2012.12.001 and 10.1016/j.molcel.2012.11.028, published online 3 Jan 2013)