Effect of heat-shock on total, poly-ubiquitylated, and insoluble proteomes of human IMR-90 fibroblasts in different proliferation states

Cellular stress responses are crucial for survival in sub-optimal conditions, and almost invar-iably involve proteome-wide alterations at the levels of protein abundance, post-translational modification with poly-ubiquitin chains (poly-ubiquitylation), and solubility. However, most of our understanding of human cell stress responses at the protein level stems from experi-ments in rapidly-dividing cell culture models. Here, we used primary human diploid lung fibro-blasts (IMR-90) in proliferating, contact-inhibited quiescent, or doxorubicin-induced senes-cent states, to explore their responses to a severe heat-shock (44 degrees Celsius for 2 hours) at the total, poly-ubiquitylated, and insoluble proteome levels.