GLUT5

GLUT5 is a glucose transporter type found in humans and other mammals. It is encoded by the SLC2A5 gene. GLUT5 is known for its specific role in the transport of fructose across the cell membrane, which is particularly important in organs that metabolize large amounts of fructose, such as the small intestine and spermatozoa.

Structure

GLUT5 is a member of the GLUT family of glucose transporters, which are integral membrane proteins that facilitate the transport of glucose across the plasma membrane. The SLC2A5 gene that encodes GLUT5 is located on chromosome 1 and consists of 10 exons. The protein itself is composed of 501 amino acids and has a molecular weight of approximately 55 kDa.

Function

GLUT5 is primarily responsible for the transport of fructose, a simple sugar that is a key source of energy for the body. Unlike other GLUT transporters, GLUT5 does not transport glucose. It is a facilitative transporter, meaning it does not require energy to transport fructose across the cell membrane. Instead, it relies on the concentration gradient of fructose, moving the sugar from areas of high concentration to areas of low concentration.

Distribution

GLUT5 is highly expressed in tissues that metabolize large amounts of fructose. These include the small intestine, where it is involved in the absorption of dietary fructose, and spermatozoa, where it provides the energy needed for sperm motility. It is also found in the kidney, fat tissue, and brain.

Clinical significance

Mutations in the SLC2A5 gene can lead to fructose malabsorption, a condition characterized by the inability to absorb fructose in the small intestine. This can result in bloating, diarrhea, and abdominal pain. In addition, because GLUT5 is the primary fructose transporter in sperm, mutations can also affect sperm motility and fertility.

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Structure of GLUT5

See also

• GLUT
• Fructose
• Sperm motility
• Fructose malabsorption