Cystinosin (CTNS) Human Recombinant Protein

This gene encodes a seven-transmembrane domain protein that functions to transport cystine out of lysosomes. Its activity is driven by the H+ electrochemical gradient of the lysosomal membrane. Mutations in this gene cause cystinosis, a lysosomal storage disorder. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2009]

CTNS: Thought to transport cystine out of lysosomes. Defects in CTNS are the cause of cystinosis nephropathic type (CTNS). It is a form of cystinosis, a lysosomal storage disease due to defective transport of cystine across the lysosomal membrane. This results in cystine accumulation and crystallization in the cells causing widespread tissue damage. The classical nephropathic form has onset in the first year of life and is characterized by a polyuro-polydipsic syndrome, marked height-weight growth delay, generalized impaired proximal tubular reabsorptive capacity, with severe fluid-electrolyte balance alterations, renal failure, ocular symptoms and other systemic complications. Defects in CTNS are the cause of cystinosis adult non- nephropathic type (CTNSANN). It is a form of cystinosis, a lysosomal storage disease due to defective transport of cystine across the lysosomal membrane. This results in cystine accumulation and crystallization in the cells causing widespread tissue damage. Cystinosis adult non-nephropathic type is characterized by ocular features and a benigne course. Patients manifest mild photophobia due to conjunctival and corneal cystine crystals. Defects in CTNS are the cause of cystinosis late-onset juvenile or adolescent nephropathic type (CTNSJAN). It is a form of cystinosis, a lysosomal storage disease due to defective transport of cystine across the lysosomal membrane. This results in cystine accumulation and crystallization in the cells causing widespread tissue damage. Late-onset juvenile or adolescent nephropathic cystinosis manifests itself first at age 10 to 12 years with proteinuria due to glomerular damage rather than with the manifestations of tubular damage that occur first in infantile cystinosis. There is no excess amino aciduria and stature is normal. Photophobia, late development of pigmentary retinopathy, and chronic headaches are features. Belongs to the cystinosin family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Membrane protein, multi-pass; Membrane protein, integral

Chromosomal Location of Human Ortholog: 17p13

Cellular Component: intermediate filament cytoskeleton; intracellular membrane-bound organelle; lysosomal membrane; lysosome; early endosome; late endosome; melanosome; integral to membrane; plasma membrane

Molecular Function: L-cystine transmembrane transporter activity

Biological Process: amino acid metabolic process; ATP metabolic process; grooming behavior; lens development in camera-type eye; melanin biosynthetic process; glutathione metabolic process; long-term memory; L-cystine transport; visual learning; brain development; cognition; adult walking behavior

Disease: Cystinosis, Adult Nonnephropathic; Cystinosis, Late-onset Juvenile Or Adolescent Nephropathic Type; Cystinosis, Nephropathic