Components Involved in Protein Translocation Across the Membrane of the Endoplasmic Reticulum
Proteins which are synthesized in the cytoplasm of eucaryotic cells can have different destinations. They can remain in the cytoplasm or be transported to a particular organelle such as the endoplasmic reticulum (ER), the mitochondria or the nucleus. The ER is the entry site to the secretory pathway for secretory, lysosomal and for those membrane proteins that become resident of the ER, the Golgi or the plasma membrane. Proteins which enter this pathway have signal sequences that guide them to the ER membrane. A typical signal sequence is about 20 amino acid residues long and its main distinctive feature is a core of hydrophobic amino acid residues. On the luminal side of the membrane the signal sequence of most presecretory proteins is cleaved by signal peptidase.
KeywordsHydrolysis Sucrose Magnesium Urea EDTA
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