NSF/SNAPs and p97/p47/VCIP135 Are Sequentially Required for Cell Cycle-Dependent Reformation of the ER Network

Genes Cells. 2005 Oct;10(10):989-99. doi: 10.1111/j.1365-2443.2005.00894.x.

Abstract

The endoplasmic reticulum (ER) has a characteristic polygonal structure with hallmark three-way junctions. In a previous paper, we reconstituted the disruption of the pre-existing ER network using mitotic cytosol from HeLa cells in streptolysin O (SLO)-permeabilized CHO-HSP cells (stably expressing GFP-HSP47). In addition, we found that interphase cytosol induced reformation of the disrupted ER network into a continuous network structure. Here, we show that the reformation of the ER network is accomplished through two sequential fusion reactions. The first process is mediated by NSF/alpha and gamma-SNAPs, and involves the generation of typical membranous intermediate structures that connect the disrupted ER tubules. A subsequent fusion is mediated by p97/p47/VCIP135, which has been shown to be required for homotypic fusion events in Golgi cisternae regrowth after mitosis. In addition, we also found that both fusion processes involve the t-SNARE, syntaxin 18.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphatases / physiology
  • Animals
  • Antibodies / metabolism
  • CHO Cells
  • Cell Cycle / physiology*
  • Cricetinae
  • Cytosol / enzymology
  • Cytosol / metabolism
  • Endopeptidases / metabolism*
  • Endopeptidases / physiology
  • Endoplasmic Reticulum / physiology*
  • Golgi Apparatus / physiology
  • Green Fluorescent Proteins / metabolism
  • Membrane Fusion / physiology
  • Microscopy, Electron
  • Microscopy, Fluorescence
  • Mitosis
  • Models, Biological
  • Nuclear Proteins / metabolism
  • Nuclear Proteins / physiology
  • Qa-SNARE Proteins / metabolism
  • Recombinant Fusion Proteins / metabolism
  • SNARE Proteins / metabolism

Substances

  • Antibodies
  • Nuclear Proteins
  • Qa-SNARE Proteins
  • Recombinant Fusion Proteins
  • SNARE Proteins
  • Green Fluorescent Proteins
  • Endopeptidases
  • VCIP135 protein, rat
  • Adenosine Triphosphatases
  • p97 ATPase