Protein quality control: chaperones culling corrupt conformations.

Achieving the correct balance between folding and degradation of misfolded proteins is critical for cell viability. The importance of defining the mechanisms and factors that mediate cytoplasmic quality control is underscored by the growing list of diseases associated with protein misfolding and aggregation. Molecular chaperones assist protein folding and also facilitate degradation of misfolded polypeptides by the ubiquitin-proteasome system. Here we discuss emerging links between folding and degradation machineries and highlight challenges for future research.