Fig. 3.

A proposed mechanism underlying the regulation of dormant cancer cells. Regulation of the UPR machinery for ER homeostasis is essential for the survival of dormant cancer cells in the presence of sustained ER stress, such as chemotherapy. RGS2 plays an important role in the survival of dormant cancer cells by maintaining protein homeostasis against chemotherapy or hostile microenvironments. ATF, activating transcription factor; ER, endoplasmic reticulum; ERAD, ER-associated protein degradation; IRE1, inositol requiring enzyme 1; PERK, protein kinase R-like endoplasmic reticulum kinase; RGS2, regulator of G protein signaling 2; Ub, ubiquitin; UPR, unfolded protein response; XBP1, X-box binding protein 1.