Coated vesicle

Definition

A coated vesicle is a small, membrane-bound structure that transports molecules within a cell, characterized by a protein coat on its cytoplasmic side. This coat is primarily made up of clathrin or other proteins, which help in the selection and concentration of specific cargo molecules for transport. Coated vesicles play a crucial role in bulk transport processes, facilitating the movement of substances between different cellular compartments.

5 Must Know Facts For Your Next Test

1. Coated vesicles are primarily involved in transporting proteins and lipids between the endoplasmic reticulum, Golgi apparatus, and the plasma membrane.
2. The formation of coated vesicles begins with the recruitment of clathrin to specific areas of the membrane, where it assembles into a basket-like structure.
3. Once the vesicle is formed, it pinches off from the membrane and sheds its coat, allowing the vesicle to fuse with its target compartment and deliver its cargo.
4. Coated vesicles are not only involved in transport but also play a role in signaling pathways by carrying receptors and other signaling molecules.
5. Different types of coated vesicles exist, including clathrin-coated vesicles for endocytosis and COP-coated vesicles for transport within the secretory pathway.

Review Questions

• How do coated vesicles contribute to the process of endocytosis?
  • Coated vesicles play a crucial role in endocytosis by facilitating the internalization of substances from the extracellular environment. The process begins with the formation of a clathrin-coated pit on the cytoplasmic side of the plasma membrane, which helps concentrate and select specific molecules for uptake. Once enough cargo is gathered, the pit invaginates and pinches off to form a coated vesicle, which transports these selected molecules into the cell.
• Compare the roles of coated vesicles in both endocytosis and exocytosis.
  • Coated vesicles serve different functions in endocytosis and exocytosis but are essential for both processes. In endocytosis, they are responsible for bringing substances into the cell by capturing specific cargo at the membrane and forming vesicles. Conversely, during exocytosis, different types of coated vesicles, such as COP-coated vesicles, transport proteins and lipids from internal compartments like the Golgi apparatus to the plasma membrane for secretion. Both processes highlight the importance of coated vesicles in maintaining cellular transport and communication.
• Evaluate the impact of defective coated vesicle formation on cellular function and overall health.
  • Defective formation of coated vesicles can severely disrupt cellular function by impairing essential transport processes such as endocytosis and exocytosis. This impairment can lead to issues such as nutrient deficiencies, accumulation of waste products, and failure to respond to external signals effectively. For instance, if clathrin-coated vesicles do not form properly, cells may struggle to internalize critical receptors or nutrients, potentially resulting in conditions like obesity or neurodegenerative diseases. Understanding these defects is vital for developing therapeutic strategies that target cellular transport mechanisms.

Related terms

Clathrin: A protein that forms a triskelion shape and plays a key role in the formation of coated vesicles during endocytosis.

Endocytosis:

The process by which cells internalize substances by engulfing them in membrane-bound vesicles.

Exocytosis:

The process of transporting molecules out of a cell by the fusion of vesicles with the plasma membrane.