1. Consider a soluble lysosomal cargo protein.

A. What is the signal that is recognized to deliver proteins to the lysosome?

B. How could you change the protein sequence of the lysosomal cargo so that it is delivered and retained in the ER instead of delivered to the lysosome?

C. You add a Nuclear Localization Sequence (NLS) onto the C-terminus of the lysosomal cargo protein sequence, expecting it to be delivered to the nucleus. However, you observe that the mutant protein is still delivered to the lysosome. Please explain why the added NLS did not change the protein’s destination.