L-cystine transport

Definition

Target type: biologicalprocess

The directed movement of L-cystine (also known as dicysteine) into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [GOC:go_curators, ISBN:0198506732]

L-cystine transport is a crucial biological process that facilitates the uptake of L-cystine, a sulfur-containing amino acid, into cells. L-cystine is a vital precursor for the synthesis of cysteine, which is essential for various cellular functions, including protein synthesis, glutathione production, and detoxification. The transport of L-cystine across cell membranes is mediated by specific transporter proteins. The primary system involved is the system xc-, an antiporter that exchanges L-cystine for glutamate. This exchange mechanism ensures that L-cystine uptake is coupled to the efflux of glutamate, maintaining cellular homeostasis. The system xc- is a sodium-independent transporter, meaning it does not require energy from the sodium gradient for its activity. The transporter is primarily located on the plasma membrane of cells, where it facilitates the bidirectional movement of L-cystine and glutamate. The activity of the system xc- is tightly regulated by various factors, including intracellular cysteine levels, oxidative stress, and the availability of glutamate. When intracellular cysteine levels are low, the system xc- becomes more active, enhancing L-cystine uptake. Conversely, high cysteine levels suppress transporter activity. The system xc- is also upregulated in response to oxidative stress, as L-cystine is a precursor for glutathione, an important antioxidant. The availability of glutamate is another critical factor influencing L-cystine transport. The system xc- requires glutamate as a substrate for the exchange reaction, and the availability of glutamate can affect the rate of L-cystine uptake. In addition to the system xc-, other transporters have been implicated in L-cystine transport, including the y+L system and the LAT1/4F2hc complex. However, the system xc- is the primary pathway for L-cystine transport in most cell types. The efficiency of L-cystine transport is crucial for maintaining cellular cysteine homeostasis and ensuring proper cellular function. Dysregulation of L-cystine transport can contribute to various pathological conditions, including neurodegenerative diseases, cancer, and cardiovascular disease.'
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Proteins (3)

Compounds (17)