pinocytosis

Definition

Target type: biologicalprocess

An endocytosis process that results in the uptake of liquid material by cells from their external environment; literally 'cell drinking'. Liquid is enclosed in vesicles, called pinosomes, formed by invagination of the plasma membrane. [ISBN:0198506732]

Pinocytosis is a cellular process that involves the uptake of fluid and small molecules from the extracellular environment into the cell through the formation of small vesicles. This process is crucial for various cellular functions, including nutrient acquisition, signal transduction, and maintaining cell volume.

Here's a detailed description of the process:

1. **Initiation:** The process begins with the formation of invaginations, or inward folds, in the cell membrane. These invaginations are triggered by the binding of specific molecules or signals to receptors on the cell surface. These receptors can be specific for nutrients, growth factors, or other extracellular molecules.

2. **Vesicle Formation:** The invaginations continue to fold inward, forming a pouch-like structure called a coated pit. The coating of the pit is typically made of a protein called clathrin, which helps in the budding and formation of the vesicle.

3. **Budding:** As the coated pit deepens, it eventually pinches off from the cell membrane, forming a small, spherical vesicle enclosed within the cell. This vesicle, now containing the ingested fluid and molecules, is called a pinocytic vesicle.

4. **Internalization:** The pinocytic vesicle detaches from the cell membrane and moves into the cytoplasm. Inside the cell, the vesicle can either fuse with other vesicles or with a larger organelle called the endosome.

5. **Processing and Delivery:** The contents of the pinocytic vesicle are processed within the endosome. Some molecules may be sorted and transported to other cellular compartments, while others may be degraded by enzymes within the endosome.

Pinocytosis is a continuous process that occurs in most cell types, playing a vital role in cellular function. It allows cells to take up nutrients, maintain their volume, and respond to various signals from their environment. It's a fundamental process that ensures the proper functioning and survival of cells.'
"

Proteins (1)

Compounds (5)