4F2A

4F2A is a protein found in humans and other mammals. It is also known as solute carrier family 2, member 1, or LAT1. This protein functions as a transporter, specifically a heterodimeric amino acid transporter. It is a member of the L-type amino acid transporter (LAT) family.

The 4F2A protein is composed of two subunits. The heavy chain is an integral membrane glycoprotein encoded by the SLC3A2 gene, and the light chain is a transmembrane protein encoded by the SLC7A5 gene. The heavy chain acts as a chaperone for the light chain, facilitating its trafficking to the plasma membrane and stabilizing it there. The light chain is the actual amino acid transporter.

4F2A is primarily responsible for the transport of large neutral amino acids across cell membranes. This includes essential amino acids like leucine, isoleucine, valine, phenylalanine, tyrosine, and tryptophan, as well as the conditionally essential amino acid glutamine. The transport mediated by 4F2A is typically sodium-independent and coupled to the influx of one amino acid with the efflux of another, a process known as countertransport.

This transporter plays a crucial role in various physiological processes, including protein synthesis, cell growth, and neurotransmitter production. It is particularly important in tissues with high rates of protein turnover or amino acid demand, such as the brain, placenta, and muscle. Dysregulation of 4F2A activity has been implicated in several diseases, including cancer, where it can contribute to altered amino acid metabolism and tumor growth.