Cationic amino acid transporter 4

Cationic Amino Acid Transporter 4 (also known as CAT-4) is a protein that in humans is encoded by the SLC7A4 gene. It is a member of the cationic amino acid transporter (CAT) family, which is a part of the larger family of amino acid transporters.

Function

The CAT-4 protein is a plasma membrane protein involved in the transport of cationic amino acids (CAAs) across the cell membrane. CAAs, such as arginine, lysine, and ornithine, play crucial roles in various cellular functions, including protein synthesis, cell signaling, and immune response.

Structure

The CAT-4 protein is composed of 14 transmembrane domains, with both the N- and C-termini located intracellularly. The protein also contains a large extracellular loop between the third and fourth transmembrane domains.

Clinical Significance

Mutations in the SLC7A4 gene can lead to a deficiency in CAT-4, which can result in a variety of health issues. These include hyperargininemia, a condition characterized by an excess of arginine in the blood, and cystinuria, a condition that causes the buildup of the amino acid cystine in the kidneys and bladder.

See Also

• Cationic amino acid transporter 1
• Cationic amino acid transporter 2
• Cationic amino acid transporter 3