A truncation mutation in TBC1D4 in a family with acanthosis nigricans and postprandial hyperinsulinemia

Satya Dash, Hiroyuki Sano, Justin J. Rochford, Robert K. Semple, Giles Yeo, Caroline S. S. Hyden, Maria A. Soos, James Clark, Andrew Rodin, Claudia Langenberg, Celine Druet, Katherine A. Fawcett, Y. C. Loraine Tung, Nicolas J. Wareham, Ines Barroso, Gustav E. Lienhard, Stephen O'Rahilly*, David B. Savage

*Corresponding author for this work

    Research output: Contribution to journalArticle

    67 Citations (Scopus)

    Abstract

    Tre-2, BUB2, CDC16, 1 domain family member 4 (TBC1D4) (AS160) is a Rab-GTPase activating protein implicated in insulin-stimulated glucose transporter 4 (GLUT4) translocation in adipocytes and myotubes. To determine whether loss-of-function mutations in TBC1D4 might impair GLUT4 translocation and cause insulin resistance in humans, we screened the coding regions of this gene in 156 severely insulinresistant patients. A female presenting at age 11 years with acanthosis nigricans and extreme postprandial hyperinsulinemia was heterozygous for a premature stop mutation (R363X) in TBC1D4. After demonstrating reduced expression of wild-type TBC1D4 protein and expression of the truncated protein in lymphocytes from the proband, we further characterized the biological effects of the truncated protein in 3T3L1 adipocytes. Prematurely truncated TBC1D4 protein tended to increase basal cell membrane GLUT4 levels (P = 0.053) and significantly reduced insulin-stimulated GLUT4 cell membrane translocation (P <0.05). When coexpressed with wild- type TBC1D4, the truncated protein dimerized with full-length TBC1D4, suggesting that the heterozygous truncated variant might interfere with its wild- type counterpart in a dominant negative fashion. Two overweight family members with the mutation also manifested normal fasting glucose and insulin levels but disproportionately elevated insulin levels following an oral glucose challenge. This family provides unique genetic evidence of TBC1D4 involvement in human insulin action.

    Original languageEnglish
    Pages (from-to)9350-9355
    Number of pages6
    JournalPNAS
    Volume106
    Issue number23
    Early online date22 May 2009
    DOIs
    Publication statusPublished - 9 Jun 2009

    Keywords

    • glucose transport
    • insulin resistance
    • AS160
    • GTPASE-activating-protein
    • GLUT4 glucose-transporter
    • beta-cell function
    • insulin-resistance
    • translocation
    • receptors
    • humans
    • AKT2
    • gap

    Cite this

    Dash, S., Sano, H., Rochford, J. J., Semple, R. K., Yeo, G., Hyden, C. S. S., ... Savage, D. B. (2009). A truncation mutation in TBC1D4 in a family with acanthosis nigricans and postprandial hyperinsulinemia. PNAS, 106(23), 9350-9355. https://doi.org/10.1073/pnas.0900909106