Epithelial neutral amino acid transporters: Lessons from mouse models

PURPOSE OF REVIEW: Epithelial neutral amino acid transporters have been identified at the molecular level in recent years. Mouse models have now established the crucial role of these transporters for systemic amino acid homeostasis. This review summarizes recent progress in this field. RECENT FINDINGS: Epithelial neutral amino acid transporters play an important role in the homeostasis of neutral amino acid levels in the body. They are important for the maintenance of body weight and muscle mass and serve as fuels. They also serve a role in providing nutrients to epithelial cells. Changes of plasma amino acid levels are not necessarily correlated to the amino acids appearing in the urine; changes in organ amino acid metabolism need to be taken into account. SUMMARY: Genetic deletion of neutral amino acid transporters provides insight into their role in protein nutrition and homeostasis.