Task: Answer Verification
Input (English): Question: Is degradation of the LDL receptors by PCSK9 mediated by a secreted protein acted upon by PCSK9 extracellularly?
Answer: Degradation of the LDLR by PCSK9 is not mediated by a secreted protein acted upon by PCSK9 extracellularly. Also the PCSK9-mediated degradation of the LDLR does not take place on the cell surface. Rather, the PCSK9-mediated degradation of the LDLR appears to take place intracellularly and occurs even when endocytosis through clathrin-coated pits is blocked by hypertonic medium.
Output (English): no