Question

You have isolated a cell that has a defective GlcNAc phosphotransferase {i.e. it lacks the binding site for GlcNAc phosphate}. Would this deficiency have any effect on targeting hydrolases from the Golgi to lysosomes? Explain your answer

1. Transport of proteins between there and Golgi Apparatus is mediated by two distinct membranes coat complexes, COP I, & COP II. Describe the formation of COP II coated vesicles budding from the ER. Be sure to include all the proteins involved.
2. Explain what happens if a soluble resident ER protein is transported to the Golgi.

Answer 1

Answer

GlcNAc phosphate is a sorting signal for any protein which is destined to locate into the lysosome from Golgi. So any cells which have defective enzymes that initiate the tagging lysosomal protein ( Hydrolases) with GlcNAc phosphate will not be targeted into the lysosome.