An experimental drug causes cytoplasmic ribosomes to aggregate and be sequestered inside a membrane-bound compartment distinct from their normal cytosolic distribution. Analyze and predict the multi-step consequences for protein synthesis and cellular physiology.

• A. Sequestration reduces functional ribosome availability for translation, decreasing protein synthesis, which may impair processes like signal transduction and metabolic enzyme production, potentially leading to cellular stress and activation of quality-control pathways.
• B. Ribosomal sequestration will cause immediate increases in mRNA transcription in the nucleus to replace the sequestered ribosomes, thereby restoring protein levels within seconds.
• C. The only consequence will be that secreted proteins are synthesized at a higher rate because aggregated ribosomes preferentially translate signal peptide–containing mRNAs while cytosolic proteins are unaffected.
• D. Aggregated ribosomes generally become more active because proximity increases peptide-bonding rates, so overall protein synthesis will increase and cells will exhibit enhanced growth and decreased stress responses.

Answer: (A)