Role of syntaxin 18 in the organization of endoplasmic reticulum subdomains

J Cell Sci. 2009 May 15;122(Pt 10):1680-90. doi: 10.1242/jcs.036103. Epub 2009 Apr 28.

Abstract

The presence of subdomains in the endoplasmic reticulum (ER) enables this organelle to perform a variety of functions, yet the mechanisms underlying their organization are poorly understood. In the present study, we show that syntaxin 18, a SNAP (soluble NSF attachment protein) receptor localized in the ER, is important for the organization of two ER subdomains, smooth/rough ER membranes and ER exit sites. Knockdown of syntaxin 18 caused a global change in ER membrane architecture, leading to the segregation of the smooth and rough ER. Furthermore, the organization of ER exit sites was markedly changed concomitantly with dispersion of the ER-Golgi intermediate compartment and the Golgi complex. These morphological changes in the ER were substantially recovered by treatment of syntaxin-18-depleted cells with brefeldin A, a reagent that stimulates retrograde membrane flow to the ER. These results suggest that syntaxin 18 has an important role in ER subdomain organization by mediating the fusion of retrograde membrane carriers with the ER membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brefeldin A / pharmacology
  • Coat Protein Complex I / metabolism
  • Endoplasmic Reticulum, Rough / drug effects
  • Endoplasmic Reticulum, Rough / metabolism*
  • Endoplasmic Reticulum, Rough / ultrastructure
  • Endoplasmic Reticulum, Smooth / drug effects
  • Endoplasmic Reticulum, Smooth / metabolism*
  • Endoplasmic Reticulum, Smooth / ultrastructure
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • HeLa Cells
  • Humans
  • Mannose-Binding Lectins / metabolism
  • Membrane Fusion*
  • Membrane Glycoproteins / metabolism
  • Membrane Proteins / metabolism
  • Protein Transport
  • Qa-SNARE Proteins / genetics
  • Qa-SNARE Proteins / metabolism*
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Transfection
  • Viral Envelope Proteins / metabolism

Substances

  • Coat Protein Complex I
  • G protein, vesicular stomatitis virus
  • LMAN1 protein, human
  • Mannose-Binding Lectins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Qa-SNARE Proteins
  • RNA, Small Interfering
  • Recombinant Fusion Proteins
  • Viral Envelope Proteins
  • Brefeldin A