cystinosin ELISA Kits

CTNS is the gene that encodes the protein cystinosin in humans. It is a lysosomal seven-transmembrane protein that functions as an active transporter for the export of cystine molecules out of the lysosome. The gene is expressed in the lysosomes of all organs and tissues. Has also been found in melanosomes in melanocytes. It is a seven-transmembrane domain receptor embedded in the lysosomal membrane, and is a member of the lysosomal cystine transporter family of transport proteins. It comprises 367 amino acid residues, and has a molecular mass of 41738 Da. Cystinosin has seven N-glycosylation sites in the N-terminus region, spanning a range of 128 amino acid residues. The receptor also has two sorting motifs; a GYDQL motif in the C-terminus region, and a YFPQA motif, known as the 'PQ loop,' on the fifth inter-transmembrane _-helix moiety.

Cystinosin functions as a symporter which actively transports protons and cystine, the oxidized cysteine dimer, out of the lysosome. This is necessary to distribute cystine to the rest of the cell and allow the lysosome to continue to function. Also been discovered in melanosomes and has been linked to the control and regulation of melanin, possibly by preventing melanosome acidification and subsequent degradation of tyrosinase TYR. Mutations in the gene can result in cystinosis. Cystinosis is a type of lysosomal transport disorder, a subset of lysosomal storage disorders. Variation in the encoded cystinosin protein results in an inhibition or loss in its ability to transport cystine out of the lysosome. Cystine molecules accumulate and form crystals within the lysosome, impairing its function. The type and extent of mutation determines the type and severity of cystinosis in the carrier.