17.8: Synthesis of Integral Membrane Proteins
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- 89014
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Integral membrane proteins may span a membrane one or more times or may simply be anchored (embedded) in the membrane at one end (Figure 17.20, below).
N-terminal signal sequences guide ribosomes translating integral membrane proteins to the RER. But before such a protein can pass completely into the RER cisternae, a stop-transfer sequence (a hydrophobic domain within the polypeptide chain) traps the protein in the fatty acid interior of the membrane. Multiple stop-transfer sequences account for transmembrane proteins that span a membrane more than once.