Mapping of R-SNARE function at distinct intracellular GLUT4 trafficking steps in adipocytes

J Cell Biol. 2008 Jan 28;180(2):375-87. doi: 10.1083/jcb.200709108.

Abstract

The functional trafficking steps used by soluble NSF attachment protein receptor (SNARE) proteins have been difficult to establish because of substantial overlap in subcellular localization and because in vitro SNARE-dependent binding and fusion reactions can be promiscuous. Therefore, to functionally identify the site of action of the vesicle-associated membrane protein (VAMP) family of R-SNAREs, we have taken advantage of the temporal requirements of adipocyte biosynthetic sorting of a dual-tagged GLUT4 reporter (myc-GLUT4-GFP) coupled with small interfering RNA gene silencing. Using this approach, we confirm the requirement of VAMP2 and VAMP7 for insulin and osmotic shock trafficking from the vesicle storage sites, respectively, and fusion with the plasma membrane. Moreover, we identify a requirement for VAMP4 for the initial biosynthetic entry of GLUT4 from the Golgi apparatus into the insulin-responsive vesicle compartment, VAMP8, for plasma membrane endocytosis and VAMP2 for sorting to the specialized insulin-responsive compartment after plasma membrane endocytosis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adipocytes / metabolism*
  • Animals
  • Cell Line
  • Endocytosis
  • Glucose Transporter Type 4 / metabolism*
  • Insulin / metabolism
  • Mice
  • Osmotic Pressure
  • Protein Transport
  • R-SNARE Proteins / genetics
  • R-SNARE Proteins / metabolism*
  • RNA, Small Interfering

Substances

  • Glucose Transporter Type 4
  • Insulin
  • R-SNARE Proteins
  • RNA, Small Interfering