cytoplasmic vesicle

Definition

Target type: cellularcomponent

A vesicle found in the cytoplasm of a cell. [GOC:ai, GOC:mah, GOC:vesicles]

Cytoplasmic vesicles are membrane-bound organelles that function as enclosed compartments within the cytoplasm of eukaryotic cells. They play a crucial role in transporting, storing, and delivering various cellular materials. Here's a detailed description of their components:

**1. Membrane:**
- The vesicle is enclosed by a phospholipid bilayer membrane that separates its internal contents from the surrounding cytoplasm.
- This membrane is selectively permeable, allowing specific molecules to enter and exit the vesicle.
- It often contains integral and peripheral proteins that act as transport channels, receptors, or enzymes involved in vesicle function.

**2. Lumen:**
- The interior space enclosed by the vesicle membrane is called the lumen.
- It contains the cargo being transported or stored, which can include:
- Proteins: Enzymes, signaling molecules, structural components
- Lipids: Fatty acids, sterols, phospholipids
- Carbohydrates: Sugars, polysaccharides
- Other molecules: Ions, metabolites, nucleic acids

**3. Associated Proteins:**
- Various proteins associate with the vesicle membrane or lumen, contributing to its function and identity:
- Motor proteins: For movement along cytoskeletal tracks (e.g., kinesin, dynein)
- Rab GTPases: Regulate vesicle targeting and fusion
- SNARE proteins: Facilitate vesicle docking and fusion with target membranes
- Clathrin and adaptins: Involved in vesicle budding and cargo selection
- Tethering factors: Bind to target membranes to initiate fusion

**4. Contents:**
- The specific contents of a vesicle determine its function and destination.
- Types of vesicles and their cargos:
- **Secretory vesicles:** Carry proteins for release outside the cell (e.g., hormones, neurotransmitters)
- **Endocytic vesicles:** Internalize materials from the extracellular environment (e.g., nutrients, pathogens)
- **Transport vesicles:** Move molecules between different cellular compartments (e.g., Golgi to ER)
- **Lysosomes:** Contain hydrolytic enzymes for degrading cellular waste and foreign materials
- **Peroxisomes:** Involved in lipid metabolism and detoxification

**5. Dynamic Nature:**
- Vesicles are dynamic structures that constantly change shape and size based on their function and cargo.
- They can bud off from other organelles, fuse with target membranes, and undergo internal modifications.
- Their movement within the cell is often mediated by cytoskeletal elements and motor proteins.

**In summary, cytoplasmic vesicles are highly specialized organelles essential for various cellular processes. Their components work together to ensure the efficient transport, storage, and delivery of crucial cellular materials.**'
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Proteins (52)

Compounds (1,056)