Fig. 1From: Protein quality control of cell stemnessThe Pathways of Protein Quality Control in Stem Cells. The four main pathways of protein quality control in stem cells are depicted here. Chaperones can facilitate the folding of polypeptides into the right structure. The unfolded protein response (UPR) is activated by misfolded proteins to aid refolding and to maintain protein homeostasis. Misfolded and damaged proteins can be degraded through the ubiquitin-proteasome system (UPS) or autophagyBack to article page