The data described here provide an analysis of the dynamic response of HeLa cell proteome to dithiothreitol (DTT) inducing stress of the endoplasmic reticulum (ER). During ER stress, accumulation of misfolded and unfolded proteins in the lumen of the ER initiates the Unfolded Protein Response (UPR), resulting in a large-scale redistribution of proteins. We used label-free mass spectrometry to monitor the proteomic changes of HeLa cells during a 30-h time course, monitoring eight time points (0, 0.5, 1, 2, 8, 16, 24, and 30 h). The data are associated with the research article “Differential dynamics of the mammalian mRNA and protein expression response to misfolding stress” [1], which discusses a core dataset of 1237 proteins. Here, we present the extended dataset of 2131 proteins. The raw mass spectrometry data and the analysis results have been deposited to the ProteomeXchange Consortium (http://proteomecentral.proteomexchange.org) via the PRIDE partner repository with the dataset identifier PRIDE: PXD002039.