Final answer:
The proteasome, with the help of ubiquitin, degrades improperly folded proteins to prevent them from causing cell damage. Chaperone molecules also assist proteins in folding correctly, which is crucial to their function and the prevention of diseases related to protein misfolding like Alzheimer's and cystic fibrosis.
Step-by-step explanation:
Misfolded proteins can be harmful to cells, but there is a mechanism in place to handle them. The proteasome is critical in detecting and destroying unwanted or improperly folded proteins before they can cause damage. This punctilious molecular machine utilizes a small protein called ubiquitin to tag defective proteins for degradation.
Under normal conditions, proteins fold into their functional three-dimensional structures immediately after being synthesized. However, various factors such as abnormal temperature or pH can lead to improper folding. To assist in correct folding, cells employ chaperones or chaperonins. These molecular helpers prevent aggregation and misfolding, ensuring the proteins achieve their correct conformation.
If a protein does misfold and cannot be refolded properly even with the help of chaperones, ubiquitin tags the defective protein, which the proteasome then recognizes. The proteasome subsequently degrades the protein, thus preventing potential cellular damage that could lead to diseases such as Alzheimer's or cystic fibrosis, conditions associated with protein misfolding.