Proteins Released into the ER Lumen are Routed to the Golgi Complex, Secretory Vesicles, Lysosomes, or Back to the ER Flashcards
Most proteins synthesized on rough ER are..?
glycoproteins
REMEMBER: initial glycosylation reactions that add these carbohydrate side chains take place in the ER, often while the growing polypeptide is still being synthesized
after polypeptides have been released into the ER lumen, glycosylated and folded, they are…?
delivered by various types of transport vesicles to their destinations within the cell
the first step in this transport pathway is…? what occurs here? what does it do next?
- the golgi complex, where further glycosylating and processing of carbohydrate side chains may occur.
- The golgi then serves as a site for sorting and distributing proteins to other locations
in the golgi complex, further glycosylation and processing of carbohydrate side chains occurs, and the proteins are sorted and distributed to other locations: for soluble proteins …
the default pathway takes them from the golgi complex to secretory vesicles that move to the cell surface and fuse with the plasma membrane, leading to secretion of such proteins from the cell
in the golgi complex, further glycosylation and processing of carbohydrate side chains occurs, and the proteins are sorted and distributed to other locations: soluble proteins that are not destined for secretion from the cell…
possess signal sequences that target each protein to its appropriate location within the endomembrane system
e.g many lysosomal proteins have side chains with mannose-6-phosphate
in the golgi complex, further glycosylation and processing of carbohydrate side chains occurs, and the proteins are sorted and distributed to other locations: proteins whose final destination is the ER
how does it work?
contain a KDEL sequence (Lys-Asp-Glu-Leu) on the C-terminus or related sequence
- the golgi complex has a receptor protein that binds the KDEL sequence and delivers the protein back to the ER
