transcytosis

Definition

Target type: biologicalprocess

The directed movement of endocytosed material through the cell and its exocytosis from the plasma membrane at the opposite side. [ISBN:0716731363]

Transcytosis is a cellular process that involves the movement of substances across a cell, from one side to the other. This process is distinct from simple diffusion or active transport, as it involves the internalization of the substance into a vesicle, its transport across the cell, and its release on the other side.

Transcytosis is a complex and highly regulated process that involves the interplay of various cellular components, including:

1. **Receptors:** These are specialized proteins on the cell surface that bind to specific cargo molecules, initiating the process of transcytosis.
2. **Vesicles:** These are small, membrane-bound sacs that form within the cell and serve as transport vehicles for the cargo.
3. **Cytoskeleton:** This is a network of protein filaments that provides structural support to the cell and facilitates the movement of vesicles within the cell.
4. **Molecular motors:** These are proteins that bind to vesicles and move them along the cytoskeletal tracks, allowing for efficient transport across the cell.

**The process of transcytosis can be broadly divided into five stages:**

1. **Binding and Internalization:** The cargo molecule binds to its receptor on the cell surface. This interaction triggers the formation of a vesicle that encloses the cargo.
2. **Vesicle Transport:** The vesicle containing the cargo moves through the cell, often guided by molecular motors that travel along cytoskeletal tracks.
3. **Fusion with the Target Membrane:** The vesicle reaches its target membrane on the opposite side of the cell and fuses with it. This fusion event releases the cargo into the extracellular space on the other side of the cell.
4. **Recycling of Receptors:** The receptor proteins that initially bound to the cargo can be recycled back to the original membrane for subsequent rounds of transcytosis.
5. **Sorting and Delivery:** Depending on the type of cargo and the cell type, transcytosis can be directed to specific destinations within the cell. For example, some cargo may be delivered to lysosomes for degradation, while others may be directed to other organelles or the plasma membrane.

**Examples of transcytosis in the body include:**

- **Transfer of antibodies from the mother's blood to the fetus across the placenta.**
- **Movement of nutrients and other essential molecules across epithelial cells lining the intestines.**
- **Transport of hormones and other signaling molecules across endothelial cells lining blood vessels.**
- **Regulation of immune responses by transporting immune cells and their signaling molecules across various barriers.**

**In summary, transcytosis is a vital cellular process that enables the selective transport of molecules across cells, playing a crucial role in various physiological functions.**'"

Proteins (4)

Compounds (390)