cysteine transmembrane transport

Definition

Target type: biologicalprocess

The directed movement of cysteine across a membrane. [GO_REF:0000069, GOC:TermGenie, PMID:17435223]

Cysteine transmembrane transport is a crucial process that involves the movement of cysteine, an essential amino acid, across cell membranes. This process is essential for maintaining cellular cysteine levels, which are required for various cellular functions, including protein synthesis, redox homeostasis, and detoxification.

Cysteine transport across the plasma membrane occurs through a variety of mechanisms, including:

- **System xc-:** This is a major transporter of cysteine across the plasma membrane. It is a sodium-independent antiporter that exchanges extracellular cysteine for intracellular glutamate. System xc- is highly expressed in various cell types, including neurons, astrocytes, and hepatocytes.

- **System L:** This is another important transporter of cysteine. It is a sodium-independent transporter that can transport various neutral amino acids, including cysteine, leucine, and isoleucine. System L is expressed in a wide range of tissues and is involved in the uptake of cysteine from the extracellular space.

- **Other transporters:** Several other transporters, including the sodium-dependent multivitamin transporter (SMVT) and the solute carrier family 7 member 11 (SLC7A11), have been implicated in cysteine transport. However, their specific roles in cysteine transport remain to be fully elucidated.

The transport of cysteine across the plasma membrane is tightly regulated and is influenced by various factors, including:

- **Cellular cysteine levels:** The intracellular cysteine concentration plays a critical role in regulating cysteine transport. When intracellular cysteine levels are low, the activity of cysteine transporters is increased to maintain cysteine homeostasis.

- **Hormonal regulation:** Hormones, such as insulin and growth hormone, can influence cysteine transport by modulating the expression and activity of cysteine transporters.

- **Oxidative stress:** Oxidative stress can increase the activity of cysteine transporters, as cysteine is required for the synthesis of glutathione, an important antioxidant.

Once inside the cell, cysteine can be utilized for various cellular processes, including:

- **Protein synthesis:** Cysteine is an essential amino acid that is required for the synthesis of all proteins.

- **Redox homeostasis:** Cysteine is a precursor for glutathione, a key antioxidant that protects cells from oxidative stress.

- **Detoxification:** Cysteine is involved in the detoxification of various xenobiotics and reactive oxygen species.

Dysregulation of cysteine transmembrane transport can lead to various pathological conditions, including:

- **Neurological disorders:** Cysteine deficiency can lead to neurological dysfunction, including seizures and cognitive impairment.

- **Cancer:** Cysteine transport is often dysregulated in cancer cells, contributing to their growth and survival.

- **Inflammatory diseases:** Cysteine transport is involved in the regulation of inflammation and can be altered in inflammatory diseases.

In conclusion, cysteine transmembrane transport is a complex and vital process that plays a crucial role in maintaining cellular homeostasis and function. Dysregulation of cysteine transport can contribute to various pathological conditions, highlighting the importance of understanding the mechanisms underlying this process.
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Proteins (2)

Compounds (15)