Question

The unfolded protein response slows the production of ________ and increases the ________.

A) signal recognition particles; activity of proteasomes
B) most proteins; production of lysosomal proteins
C) protein disulfide isomerase; activity of proteasomes
D) most proteins; production of proteins required for protein folding and degradation

Answer 1

The unfolded protein response reduces the production of most proteins and elevates the production of proteins that aid in protein folding and degradation, helping cells manage ER stress.

Step-by-step explanation:

The unfolded protein response (UPR) is a cellular stress response mechanism related to the endoplasmic reticulum (ER) stress. Specifically, the UPR will slow the production of most proteins and increase the production of proteins that are required for protein folding and degradation. This adjustment in protein synthesis and processing allows the cell to cope with the stress of misfolded proteins within the ER by reducing the load of new proteins entering the ER while simultaneously increasing the cell's capacity to refold or degrade misfolded proteins.

Key components involved in protein degradation, like ubiquitin-proteasomes, are upregulated to enhance the elimination of damaged or misfolded proteins. Also, chaperone proteins, including the heat-shock proteins (HSPs), are increased to assist in protein folding, which is essential to alleviate ER stress. Thus, the correct answer to the question is: The unfolded protein response slows the production of most proteins and increases the production of proteins required for protein folding and degradation.

Answer 2

The unfolded protein response slows the production of most proteins and increases the production of proteins required for protein folding and degradation. This process helps in regulating protein quality control within the endoplasmic reticulum and maintaining cellular homeostasis. Option D is the correct answer.

Step-by-step explanation:

When students inquire about the unfolded protein response (UPR), they are exploring a cellular stress response related to the endoplasmic reticulum (ER). The UPR occurs when there is an accumulation of unfolded or misfolded proteins in the ER. This response adjusts the cell's protein folding capacity by slowing down the production of most proteins and increasing the production of proteins required for protein folding and degradation.

The UPR mechanism involves several steps, including (1) removal of signal sequences that direct proteins to cellular compartments, (2) proper folding of polypeptides often facilitated by chaperone proteins, (3) proteolytic processing of proteins, and (4) various chemical modifications such as phosphorylation. A key player in protein degradation is ubiquitin, which tags proteins for destruction by the proteasome complex.

Thus, the unfolded protein response slows the production of most proteins and increases the production of proteins required for protein folding and degradation, making the correct option 'D'. Proteins such as protein disulfide isomerase and molecular chaperones like HSP70 help in the correct folding of newly synthesized proteins, while ubiquitin-proteasome systems degrade misfolded or unwanted proteins.