title: OCTN cation transporters in health and disease: role as drug targets and assay development.
abstract: The three members of the organic cation transporter novel subfamily are known to be involved in interactions with xenobiotic compounds. These proteins are characterized by 12 transmembrane segments connected by nine short loops and two large hydrophilic loops. It has been recently pointed out that acetylcholine is a physiological substrate of OCTN1. Its transport could be involved in nonneuronal cholinergic functions. OCTN2 maintains the carnitine homeostasis, resulting from intestinal absorption, distribution to tissues, and renal excretion/reabsorption. OCTN3, identified only in mouse, mediates also carnitine transport. OCTN1 and OCTN2 are associated with several pathologies, such as inflammatory bowel disease, primary carnitine deficiency, diabetes, neurological disorders, and cancer, thus representing useful pharmacological targets. The function and interaction with drugs of OCTNs have been studied in intact cell systems and in proteoliposomes. The latter experimental model enables reduced interference from other transporters or enzyme pathways. Using proteoliposomes, the molecular bases of toxicity of some drugs have recently been revealed. Therefore, proteoliposomes represent a promising experimental tool suitable for large-scale molecular screening of interactions of OCTNs with chemicals regarding human health.
authors.affiliation: Laboratory of Biochemistry and Molecular Biotechnology, Department BEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Italy.
authors.forename: Lorena
authors.initials: L
authors.lastname: Pochini
authors.forename: Mariafrancesca
authors.initials: M
authors.lastname: Scalise
authors.forename: Michele
authors.initials: M
authors.lastname: Galluccio
authors.forename: Cesare
authors.initials: C
authors.lastname: Indiveri
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002331:Carnitine / Q000378:metabolism*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000378:metabolism; D027701:Organic Cation Transport Proteins / Q000187:drug effects / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism; D000074058:Solute Carrier Family 22 Member 5; D027981:Symporters
chemical_list: D027701:Organic Cation Transport Proteins; D011510:Proteolipids; C109807:SLC22A4 protein, human; C492020:SLC22A5 protein, human; C498687:Slc22a21 protein, mouse; D000074058:Solute Carrier Family 22 Member 5; D027981:Symporters; C020485:proteoliposomes; D000109:Acetylcholine; D002331:Carnitine
keywords: OCTN; acetylcholine; carnitine; drugs; review; transporters