This binding restarts the process of protein assembly, and the
growing polypeptide chain is fed through a protein complex
in the endoplasmic reticulum membrane into the lumen of the
). Upon completion of protein assem-
bly, proteins that are to be secreted end up in the lumen of
the rough endoplasmic reticulum. Proteins that are destined
to function as integral membrane proteins remain embedded
in the reticulum membrane.
mRNA from gene A
mRNA from gene B
from gene A
Pathway of proteins destined to be secreted by cells or transferred to lysosomes. An example of the latter might be a protein important in
digestive functions in which a cell degrades other intracellular molecules.