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LAAT-1 is the lysosomal lysine/arginine transporter that maintains amino acid homeostasis.

Science (New York, N.Y.) (2012-07-24)
Bin Liu, Hongwei Du, Rachael Rutkowski, Anton Gartner, Xiaochen Wang
ABSTRACT

Defective catabolite export from lysosomes results in lysosomal storage diseases in humans. Mutations in the cystine transporter gene CTNS cause cystinosis, but other lysosomal amino acid transporters are poorly characterized at the molecular level. Here, we identified the Caenorhabditis elegans lysosomal lysine/arginine transporter LAAT-1. Loss of laat-1 caused accumulation of lysine and arginine in enlarged, degradation-defective lysosomes. In mutants of ctns-1 (C. elegans homolog of CTNS), LAAT-1 was required to reduce lysosomal cystine levels and suppress lysosome enlargement by cysteamine, a drug that alleviates cystinosis by converting cystine to a lysine analog. LAAT-1 also maintained availability of cytosolic lysine/arginine during embryogenesis. Thus, LAAT-1 is the lysosomal lysine/arginine transporter, which suggests a molecular explanation for how cysteamine alleviates a lysosomal storage disease.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Cysteamine hydrochloride, ≥98% (titration)
Sigma-Aldrich
Cysteamine, ~95%
Sigma-Aldrich
Cysteamine, ≥98.0% (RT)
Sigma-Aldrich
Cysteamine hydrochloride, BioXtra
Sigma-Aldrich
Cysteamine hydrochloride, ≥97.0% (RT)