cysteine transport

Definition

Target type: biologicalprocess

The directed movement of cysteine into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [GOC:jl, ISBN:0198506732]

Cysteine transport is a crucial biological process that ensures the delivery of this essential amino acid to cells for various metabolic functions. Cysteine is a sulfur-containing amino acid that is essential for protein synthesis, antioxidant defense, and the production of glutathione, a critical molecule involved in detoxification. The transport of cysteine across cell membranes is a complex process that involves multiple membrane transporters and intracellular pathways.

There are two main types of cysteine transport systems:

1. **System Xc- :** This transporter is an antiporter that exchanges cysteine for glutamate across the plasma membrane. It is a sodium-independent transporter and is responsible for the majority of cysteine uptake in many cell types. System Xc- is also known as the cystine/glutamate exchanger, as it preferentially transports cystine, the oxidized form of cysteine.

2. **Sodium-dependent transporters:** These transporters utilize the electrochemical gradient of sodium ions to drive cysteine uptake. They are typically specific for cysteine and are found in various tissues, including the liver, kidney, and intestine.

The transport of cysteine across the plasma membrane is regulated by multiple factors, including:

- **Cellular cysteine levels:** When intracellular cysteine levels are low, the expression of cysteine transporters is upregulated to increase cysteine uptake.
- **Oxidative stress:** Oxidative stress can stimulate the expression of cysteine transporters to increase the availability of cysteine for glutathione synthesis.
- **Hormonal regulation:** Hormones such as insulin and growth hormone can modulate the expression of cysteine transporters.

Once cysteine is transported into the cell, it can be utilized for various metabolic processes, including:

- **Protein synthesis:** Cysteine is incorporated into proteins during translation.
- **Glutathione synthesis:** Cysteine is a precursor for the synthesis of glutathione, a powerful antioxidant that protects cells from oxidative damage.
- **Hydrogen sulfide production:** Cysteine is a precursor for the production of hydrogen sulfide (H2S), a signaling molecule that plays a role in various physiological processes.

**Disruption of cysteine transport can have significant consequences for cellular function and health. For example, defects in cysteine transport have been implicated in various diseases, including:**

- **Cystic fibrosis:** Defective cysteine transport can contribute to the accumulation of thick mucus in the lungs, a hallmark of cystic fibrosis.
- **Neurodegenerative diseases:** Cysteine deficiency can impair neuronal function and contribute to the progression of neurodegenerative diseases.
- **Cancer:** Dysregulation of cysteine transport can promote tumor growth and metastasis.

In summary, cysteine transport is a critical process that ensures the supply of this essential amino acid to cells for various metabolic functions. The transport of cysteine is tightly regulated by cellular needs, oxidative stress, and hormonal factors. Disruption of cysteine transport can lead to various diseases, highlighting the importance of this process for maintaining cellular and organismal health.'
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Proteins (1)

Compounds (13)