In addition to protein phosphorylation and dephosphorylation, protein degradation also plays key role in regulating signal transduction pathways and cell proliferation. Please answer the following questions:

(1). Please give one example to describe how protein degradation regulates signal transduction pathway;

(2) Please give another example to describe how protein degradation affects cell proliferation.

(3). Do you think targeting protein degradation process could be an effective cancer therapeutic strategy? If your answer is YES, please describe which protein involving protein degradation process could be a good drug target for cancer therapy and how to design the drug targeting it? If your answer is NO, please explain why.