Lysosomal Amino Acid Efflux Assay

Abstract

As the cellular “recycling” organelle, lysosomes break down proteins into amino acids, which are then transported into cytosol for reuse by various amino acid transporters. The transport rate of an amino acid is presumably regulated by cellular conditions such as organelle pH, membrane potential and metabolic states. Because of their intracellular localization and the relative inaccessibility, lysosomal amino acid transporters have been studied largely via indirect measurements. Using lysosome purification and 14C-labeled amino acids, this protocol provides a method to measure the efficiency of specific amino acid transporters on lysosomes.