Final answer:
Misfolded proteins in the ER are recognized and degraded through ER-associated degradation (ERAD). Molecular chaperones assist in refolding misfolded proteins, while ubiquitin ligases mark them for degradation. The proteasome carries out the degradation.
Step-by-step explanation:
When proteins misfold in the endoplasmic reticulum (ER), they are recognized by a quality control system. The misfolded proteins are then targeted for degradation. The process of recognizing and degrading misfolded proteins is known as ER-associated degradation (ERAD).
Multiple proteins are involved in the ERAD process. Some of these proteins include molecular chaperones, which assist in refolding misfolded proteins, and ubiquitin ligases, which mark the misfolded proteins for degradation by attaching ubiquitin molecules to them. Additionally, the proteasome, a large complex of polypeptides, is responsible for the actual degradation of the tagged proteins.