Question

How do clathrin-coated vesicles select their cargo molecules?

A. specific cargo molecules have a high affinity for clathrin
B. cargo is selected randomly and is sorted later in the endosomes
C. Cargo receptors bind specifically to cargo proteins and to clathrin
D. cargo is actively transported into preformed clathrin-coated vesicles

Answer 1

Clathrin-coated vesicles use receptor-mediated endocytosis to transport specific cargo proteins into the cell. Cargo receptors bind specific proteins and to clathrin indirectly via adaptor proteins. The process is highly selective, ensuring that specific substances are imported into the cell.

Step-by-step explanation:

Clathrin-coated vesicles select their cargo through a process known as receptor-mediated endocytosis. This precise mechanism relies on cargo receptors that have specific binding affinities for certain cargo proteins. The cargo receptors bind to the clathrin indirectly through adaptor proteins such as AP1. During the formation of clathrin-coated vesicles, the cargo receptor proteins in the membrane bind specific packaged proteins, which are now termed cargo proteins. Following this, with the aid of clathrin and other proteins, the cargo protein-bound receptor proteins bud off from the trans Golgi stack forming vesicles that cater to different cellular or extracellular destinations.

Upon the aggregation of receptors and their ligands in the coated pits on the cell membrane, the pits invaginate and pinch off, becoming clathrin-coated vesicles. This delivers the cargo into the cell. These vesicles, once internalized, lose their coat and eventually fuse with early endosomes for sorting. The receptors are typically recycled to the plasma membrane, while the cargo is directed either to lysosomes for degradation or otherwise utilized by the cell.