Signal sequences and rough ER targeting
A protein destined for secretion is made with an N-terminal signal sequence. What does this sequence direct?
Answer D: explanation for every choice
A
Nuclear import uses a nuclear localization signal.
B
Mitochondrial import uses a mitochondrial targeting sequence.
C
Proteasomal degradation is signaled by ubiquitin tagging.
D
Correct. The SRP recognizes the signal peptide and brings the ribosome to the rough ER. The protein then moves through the Golgi to secretion.
TakeawaySignal peptide → SRP → rough ER → Golgi → secretion.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb45.