Question

Identify other targets of proteins originating from the ER besides the cis-Golgi network.

Answer 1

The proteins which are synthesized by the ribosomes in the rough ER are the part of endomemdrane system. The synthesis of protein begins in the cytosol which is later brought to the rough ER. Once the synthesis of protein is done in the rough ER lumen the protein undergo post translational modification in the ER itself. From the ER proteins are packed into vesicle and sorted to cis-Golgi network. From cis Golgi network via the medial Golgi the protein sorted to trans Golgi network. Now from trans Golgi network protein can be delivered to the plasma membrane, can be delivered to the outside the cell (secretory protein ), to the lysosome depending on the signal sequence present in the protein

So apart from cis Golgi network the protein synthesized in the ER can be targeted to outside the cells, to the lysosome, in the plasma membrane.