Glucose 6-phosphate transport in fibroblast microsomes from glycogen storage disease type 1b patients: evidence for multiple glucose 6-phosphate transport systems

Rosanna Leuzzi, Rosella Fulceri, Paola Marcolongo, Gábor Banhegyi, Enrico Zammarchi, Kirsten Stafford, Ann Burchell, Angelo Benedetti

    Research output: Contribution to journalArticlepeer-review

    21 Citations (Scopus)

    Abstract

    In liver endoplasmic reticulum the intralumenal glucose-6-phosphatase activity requires the operation of a glucose 6-phosphate transporter (G6PT1). Mutations in the gene encoding G6PT1 cause glycogen storage disease type 1b, which is characterized by a loss of glucose-6-phosphatase activity and impaired glucose homoeostasis. We describe a novel glucose 6-phosphate (G6P) transport activity in microsomes from human fibroblasts and HeLa cells. This transport activity is unrelated to G6PT1 since: (i) it was similar in microsomes of skin fibroblasts from glycogen storage disease type 1b patients homozygous for mutations of the G6PT1 gene, and in microsomes from human control subjects; (ii) it was insensitive to the G6PT1 inhibitor chlorogenic acid; and (iii) it was equally active towards G6P and glucose 1-phosphate, whereas G6PT1 is highly selective for G6P. Taken together, our results provide evidence for the presence of multiple transporters for G6P (and other hexose phosphoesters) in the endoplasmic reticulum.
    Original languageEnglish
    Pages (from-to)557-562
    Number of pages6
    JournalBiochemical Journal
    Volume357
    Issue number2
    Publication statusPublished - Jul 2001

    Keywords

    • Glucose-6-phosphatase system
    • Hexose phosphate transport system
    • von Gierke's disease
    • Endoplasmic reticulum
    • Glucose-6-phosphate translocase

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