title: Identification of protein components of the microsomal glucose 6-phosphate transporter by photoaffinity labelling.
abstract: The glucose-6-phosphatase system catalyses the terminal step of hepatic glucose production from both gluconeogenesis and glycogenolysis and is thus a key regulatory factor of blood glucose homoeostasis. To identify the glucose 6-phosphate transporter T1, we have performed photoaffinity labelling of human and rat liver microsomes by using the specific photoreactive glucose-6-phosphate translocase inhibitors S 0957 and S 1743. Membrane proteins of molecular mass 70, 55, 33 and 31 kDa were labelled in human microsomes by [3H]S 0957, whereas in rat liver microsomes bands at 95, 70, 57, 54, 50, 41, 33 and 31 kDa were detectable. The photoprobe [3H]S 1743 led to the predominant labelling of a 57 kDa and a 50 kDa protein in the rat. Stripping of microsomes with 0.3% CHAPS retains the specific binding of T1 inhibitors; photoaffinity labelling of such CHAPS-treated microsomes resulted in the labelling of membrane proteins of molecular mass 55, 33 and 31 kDa in human liver and 50, 33 and 31 kDa in rat liver. Photoaffinity labelling of human liver tissue samples from a healthy individual and from liver samples of patients with a diagnosed glycogen-storage disease type 1b (GSD type 1b; von Gierke's disease) revealed the absence of the 55 kDa protein from one of the patients with GSD type 1. These findings support the identity of the glucose 6-phosphate transporter T1, with endoplasmic reticulum protein of molecular mass 50 kDa in rat liver and 55 kDa in human liver.
authors.affiliation: Hoechst Marion Roussel Deutschland GmbH, DG Metabolic Diseases, D-65926 Frankfurt am Main, Germany. Werner.Kramerhmrag.com
authors.forename: W
authors.initials: W
authors.lastname: Kramer
authors.forename: H J
authors.initials: HJ
authors.lastname: Burger
authors.forename: W J
authors.initials: WJ
authors.lastname: Arion
authors.forename: D
authors.initials: D
authors.lastname: Corsiero
authors.forename: F
authors.initials: F
authors.lastname: Girbig
authors.forename: C
authors.initials: C
authors.lastname: Weyland
authors.forename: H
authors.initials: H
authors.lastname: Hemmerle
authors.forename: S
authors.initials: S
authors.lastname: Petry
authors.forename: P
authors.initials: P
authors.lastname: Habermann
authors.forename: A
authors.initials: A
authors.lastname: Herling
mesh_terms: D000328:Adult; D000818:Animals; D017920:Antiporters / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D001386:Azides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D002648:Child; D002726:Chlorogenic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002793:Cholic Acids / Q000378:metabolism; D003432:Cross-Linking Reagents; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005260:Female; D005952:Glucose-6-Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism; D019298:Glucose-6-Phosphate / Q000378:metabolism; D005953:Glycogen Storage Disease Type I / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism*; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D017830:Octoxynol / Q000378:metabolism; D019920:Photoaffinity Labels / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D013449:Sulfonamides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
chemical_list: D017920:Antiporters; D001386:Azides; D002793:Cholic Acids; D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D019920:Photoaffinity Labels; C119523:S 0957; C119524:S 1743; C503531:SLC37A4 protein, human; C503533:Slc37a4 protein, rat; D013449:Sulfonamides; C111261:glucose 6-phosphate(transporter); D002726:Chlorogenic Acid; D019298:Glucose-6-Phosphate; D017830:Octoxynol; D005952:Glucose-6-Phosphatase; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate