adenosine transport

Definition

Target type: biologicalprocess

The directed movement of adenosine, adenine riboside, into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [GOC:mah]

Adenosine transport is a fundamental process in cellular physiology, involving the movement of adenosine across cell membranes. Adenosine, a purine nucleoside, plays a crucial role in various biological processes, including neurotransmission, inflammation, and energy metabolism. The transport of adenosine across cell membranes is mediated by a family of membrane-bound proteins known as nucleoside transporters (NTs). These transporters are responsible for the uptake and efflux of adenosine and other nucleosides, contributing to the regulation of adenosine levels both intracellularly and extracellularly.

There are two main types of adenosine transporters: equilibrative nucleoside transporters (ENTs) and concentrative nucleoside transporters (CNTs). ENTs facilitate the bidirectional transport of adenosine across the membrane, driven by the concentration gradient. They do not require energy and are responsible for the passive diffusion of adenosine. CNTs, on the other hand, are active transporters that utilize energy from the hydrolysis of ATP to transport adenosine against its concentration gradient. This allows for the accumulation of adenosine inside cells.

ENTs are further subdivided into two subtypes: ENT1 and ENT2. ENT1 is the most abundant nucleoside transporter in many tissues, including the brain, heart, and skeletal muscle. It exhibits a high affinity for adenosine and plays a significant role in the regulation of extracellular adenosine levels. ENT2 is less abundant and exhibits lower affinity for adenosine compared to ENT1. It is primarily involved in the uptake of adenosine in the liver and kidney.

CNTs are also classified into subtypes: CNT1, CNT2, and CNT3. CNT1 is the primary transporter responsible for the uptake of adenosine in the intestine and kidney. It exhibits a high affinity for adenosine and plays a crucial role in the absorption of adenosine from the diet. CNT2 is expressed in the brain, heart, and skeletal muscle. It transports adenosine with a lower affinity compared to CNT1. CNT3 is primarily localized to the liver and kidney and exhibits a low affinity for adenosine.

The transport of adenosine across cell membranes is a complex process regulated by various factors, including the concentration of adenosine, the expression levels of nucleoside transporters, and the presence of inhibitors. Dysregulation of adenosine transport can lead to various pathological conditions, such as neurodegenerative diseases, cardiovascular diseases, and inflammatory disorders. Therefore, understanding the mechanisms of adenosine transport is crucial for developing novel therapeutic strategies targeting these diseases.
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Proteins (4)

Compounds (22)