Amino acid transporters as tetraspanin TM4SF5 binding partners

Abstract

Cell biology: troubles with trafficking Interactions between a membrane protein and transporters that move amino acids in and out of cells may play a prominent role in various diseases. The transmembrane protein TM4SF5 is known to regulate the activity of diverse signaling pathways, and has been linked to various liver diseases. Jung Weon Lee and colleagues at Seoul National University review the recently identified interplay between TM4SF5 and transporter proteins that regulate trafficking of the amino acids cysteine and arginine. Through its interactions with cysteine transporters, TM4SF5 appears to contribute to hormetic production of damaging chemicals that can cause the tissue scarring underlying idiopathic pulmonary fibrosis. Evidence also suggests that TM4SF5-facilitated arginine trafficking may contribute to liver cancer recurrence. This protein may also interact with other prominent transporters, and the authors conclude that TM4SF5 may affect other, still undefined pathological processes.