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Genetic Information
Universal
Protein Folding & Quality Control
Chaperone-assisted folding and ER quality control of newly synthesized proteins.
Overview
Protein folding is guided by molecular chaperones that prevent aggregation and assist proper conformational maturation. Cytoplasmic chaperones (Hsp70, Hsp90, chaperonins/TriC) assist soluble proteins. In the ER, the calnexin/calreticulin cycle monitors glycoprotein folding. Misfolded proteins are retrotranslocated for ER-associated degradation (ERAD) via the ubiquitin-proteasome system. The unfolded protein response (UPR) activates when ER stress exceeds capacity.
Cellular Location
Cytoplasm, ER, mitochondria
Clinical Significance
Misfolding causes Alzheimer's (Aβ), Parkinson's (α-synuclein), Huntington's, prion diseases; proteostasis decline underlies aging; Hsp90 inhibitors in cancer trials.