Sorting of GLUT4 into its insulin-sensitive store requires the Sec1/Munc18 protein mVps45

Jennifer Roccisana, Jessica B. A. Sadler, Nia J. Bryant, Gwyn W. Gould

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Insulin stimulates glucose transport in fat and muscle cells by regulating delivery of the facilitative glucose transporter, glucose transporter isoform 4 (GLUT4), to the plasma membrane. In the absence of insulin, GLUT4 is sequestered away from the general recycling endosomal pathway into specialized vesicles, referred to as GLUT4-storage vesicles. Understanding the sorting of GLUT4 into this store is a major challenge. Here we examine the role of the Sec1/Munc18 protein mVps45 in GLUT4 trafficking. We show that mVps45 is up-regulated upon differentiation of 3T3-L1 fibroblasts into adipocytes and is expressed at stoichiometric levels with its cognate target-soluble N-ethylmaleimide-sensitive factor attachment protein receptor, syntaxin 16. Depletion of mVps45 in 3T3-L1 adipocytes results in decreased GLUT4 levels and impaired insulin-stimulated glucose transport. Using subcellular fractionation and an in vitro assay for GLUT4-storage vesicle formation, we show that mVps45 is required to correctly traffic GLUT4 into this compartment. Collectively our data reveal a crucial role for mVps45 in the delivery of GLUT4 into its specialized, insulin-regulated compartment.

Original languageEnglish
Pages (from-to)2389-2397
Number of pages9
JournalMolecular Biology of the Cell
Volume24
Issue number15
DOIs
Publication statusPublished - 1 Aug 2013

Keywords

  • GLUT4
  • insulin
  • glucose transport

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