This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Clathrin is associated with which of the following functions? 
Select and explain. 
A. Pinocytosis, B. Adhesion, C. Coagulation, D. None of the above
A: Pinocytosis
Answer: A: Pinocytosis 
Explanation: Clathrin-mediated endocytosis occurs at membrane indentations where the protein clathrin accumulates. Pinocystosis is endocytosis known as 'cell drinking'. Clathrin molecules have the shape of triskelions, with three "legs" radiating from a central hub. As endocytosis progresses, the clathrin molecules form a geometric array that surrounds the endocytotic vesicle. Ref: Ganong's Review of Medical Physiology 23rd edition, Chapter 2.