Given below are a few steps in clathrin-coated vesicle formation in the secretory pathway:

(A) Receptor-ligand recognition and binding

(B) Recruitment of adapter protein and clathrin

(C) Vesicle formation

(D) Uncoating of clathrin coats

Choose the option that correctly identifies the sequence of events in making a clathrin-coated vesicle:

Correct option is A

Explanation-

Steps of Clathrin-Coated Vesicle Formation:
Step A: Receptor-ligand recognition and binding
This is the first step where specific ligands (cargo) bind to their respective receptors on the membrane. These receptors have cytoplasmic tails that signal the initiation of vesicle formation.
Step B: Recruitment of adapter proteins and clathrin
After receptor-ligand binding, adapter proteins (like AP2) are recruited to bind the receptor. These adapters then recruit clathrin triskelions, which start assembling into a coat. This clathrin coat induces membrane curvature.
Step C: Vesicle formation
As clathrin polymerizes, it drives the budding of a vesicle. A protein like dynamin helps pinch off the vesicle from the membrane.
Step D: Uncoating of clathrin coats
Once the vesicle is fully formed and internalized, clathrin and adaptor proteins are removed (uncoated). This is essential so the vesicle can fuse with target compartments like early endosomes.
Correct Sequence:
A → B → C → D

So, correct option A -  A, B, C, D