Receptor mediated endocytosis | Detailed Animation on Receptor-mediated Endocytosis| Endocytosis

Summary

This video explains receptor-mediated endocytosis, a process where cells absorb substances through receptor-ligand interactions. It begins at the cell surface with ligand binding to receptors, followed by the recruitment of adapter proteins and membrane curvature. Clathrin proteins form a vesicle, which is pinched off by dynamin. The vesicle fuses with an endosome, where ligands dissociate from receptors due to low pH. Various outcomes include recycling or degradation of receptors and ligands, as seen in LDL, transferrin, and EGFR cases. The video also provides links to additional learning resources.

Takeaways

• 🔬 Endocytosis is a cellular process where substances are brought into the cell.
• 📂 There are three types of endocytosis: receptor-mediated endocytosis, phagocytosis, and pinocytosis.
• 🔗 Receptor-mediated endocytosis involves interaction between ligands and receptors on the cell surface.
• 🧬 After ligand binding, adapter proteins are recruited to the cytosolic side of the receptor, which is crucial for the process.
• 🔄 Bar family proteins help curve the membrane to invaginate it toward the cytoplasmic side.
• 🧫 Clathrin proteins organize and form a clathrin-coated vesicle, which is then pinched off by dynamin.
• 🔄 Once internalized, the vesicle fuses with an endosome, where the low pH causes the receptor and ligand to dissociate.
• ♻️ The receptor and ligand can be recycled or degraded, depending on the situation.
• 🧪 In LDL endocytosis, the LDL receptor is recycled while the LDL particle is degraded.
• ⚙️ For epidermal growth factor receptors, both the receptor and ligand are degraded to regulate signaling.

Q & A

What is endocytosis?

Endocytosis is a cellular process in which substances are brought into the cell.

What are the three categories of endocytosis?

The three categories of endocytosis are receptor-mediated endocytosis, phagocytosis, and pinocytosis.

What is receptor-mediated endocytosis?

Receptor-mediated endocytosis is a process where specific molecules (ligands) bind to receptors on the cell surface, triggering the internalization of these molecules into the cell through vesicles.

What happens when a ligand binds to a receptor in receptor-mediated endocytosis?

When a ligand binds to a receptor, adapter proteins are recruited on the cytosolic side of the receptor, initiating the process of membrane curvature and vesicle formation.

What role do clathrin proteins play in receptor-mediated endocytosis?

Clathrin proteins organize themselves with the help of adapter proteins to form a clathrin-coated vesicle, which helps in the internalization of the ligand-receptor complex.

What is the function of dynamin in receptor-mediated endocytosis?

Dynamin is responsible for pinching off the clathrin-coated vesicle from the membrane, allowing it to be internalized into the cell.

What happens to the receptor-ligand complex once inside the cell?

Once inside the cell, the vesicle can fuse with the endosome, where the low pH environment causes the dissociation of the ligands from the receptors.

What are the possible fates of receptors and ligands after endocytosis?

There are three possible outcomes: (1) the receptor is recycled, and the ligand is degraded, (2) both the receptor and ligand are recycled, or (3) both the receptor and ligand are degraded.

Can you provide an example of receptor recycling and ligand degradation?

In LDL endocytosis, the LDL particle is digested inside the endosome, while the LDL receptor is recycled back to the cell surface.

What happens to both the receptor and ligand in epidermal growth factor receptor (EGFR) signaling?

In EGFR signaling, both the receptor and ligand are degraded, which helps regulate the signaling pathway.