title: The signature motif in human glucose-6-phosphate transporter is essential for microsomal transport of glucose-6-phosphate.
abstract: Glycogen storage disease type Ib (GSD-Ib) is caused by a deficiency in the glucose-6-phosphate transporter (G6PT). Sequence alignments identify a signature motif shared by G6PT and a family of transporters of phosphorylated metabolites. Two null signature motif mutations have been identified in the G6PT gene of GSD-Ib patients. In this study, we characterize the activity of seven additional mutants within the motif. Five mutants lack microsomal G6P uptake activity and one retains residual activity, suggesting that in G6PT the signature motif is a functional element required for microsomal glucose-6-phosphate transport.
authors.affiliation: Section on Cellular Differentiation, Heritable Disorders Branch, National Institute of Child Health and Human Development, Building 10, Room 9S241, National Institutes of Health, Bethesda, MD 20892-1830, USA.
authors.forename: Chi-Jiunn
authors.initials: CJ
authors.lastname: Pan
authors.forename: Li-Yuan
authors.initials: LY
authors.lastname: Chen
authors.forename: Brian C
authors.initials: BC
authors.lastname: Mansfield
authors.forename: Barbara
authors.initials: B
authors.lastname: Salani
authors.forename: Luigi
authors.initials: L
authors.lastname: Varesio
authors.forename: Janice Yang
authors.initials: JY
authors.lastname: Chou
mesh_terms: D000595:Amino Acid Sequence; D017920:Antiporters; D015153:Blotting, Western; D019298:Glucose-6-Phosphate / Q000378:metabolism*; D005953:Glycogen Storage Disease Type I / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008861:Microsomes / Q000378:metabolism*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D010770:Phosphotransferases / Q000172:deficiency* / Q000235:genetics*
chemical_list: D017920:Antiporters; D009004:Monosaccharide Transport Proteins; C503531:SLC37A4 protein, human; C111261:glucose 6-phosphate(transporter); D019298:Glucose-6-Phosphate; D010770:Phosphotransferases