Molecular Basis for Cystine Transport via Cystinosin (CTNS).

This research project seeks to determine the molecular basis for the autosomal recessive lysosomal storage disorder, Cystinosis. Cystinosis is caused by mutations in the CTNS gene encoding the carrier protein cystinosin, responsible for transporting cystine out of the lysosomal compartment. Defective cystinosin function leads to intra-lysosomal cystine accumulation in all body cells and organs. The kidneys are initially affected during the first year of life through proximal tubular damage followed by progressive glomerular damage and end stage renal failure during mid-childhood if not treated. Other affected organs include eyes, thyroid, pancreas, gonads, muscles and CNS. Leucocyte cystine assay is the cornerstone for both diagnosis and therapeutic monitoring of the disease. Although several lines of treatment are available for cystinosis no curative treatment is yet available. This proposal seeks to understand the molecular basis for CTNS function in the lysosome and pave the way for developing novel routes to treat this disease.