Question

The movements of newly synthesized proteins can be followed through cells using a "pulse-chase" experiment.  During synthesis, proteins are tagged with a radioactive isotope (the "pulse"), then the cells are allowed to process the proteins for varying periods of time.  The locations of the radioactive proteins are then determined by isolating cell organelles and quantifying their levels of radioactivity. What would be the expected pathway for a protein that is secreted from the cell?

Answer 1

the above image shows the secretory pathway of a protein. Newly synthesized proteins are inserted into the lumen of the ER. Those proteins that are transported out of the ER may then pass through the various subcompartments of the Golgi until they reach the trans-Golgi network, the exit side of the Golgi. In the trans-Golgi network, Proteins are segregated and sorted. proteins destined for the plasma membrane or those that are secreted in a constitutive manner are carried out to the cell surface in transport vesicles.