Updated project metadata. Heat-shock is an acute insult to the mammalian proteome. The sudden elevation in temperature has far-reaching effects on protein metabolism, leads to a rapid inhibition of most protein synthesis, and the induction of protein chaperones. Using heat-shock in human HEK293 cells, in conjunction with detergent extraction and sedimentation followed by LC-MS/MS proteomic approaches, we identify proteins that lose solubility upon heat-shock. We assume that these are metastable in protein homeostasis.