The microtubule-dependent formation of a tubulovesicular network with characteristics of the ER from cultured cell extracts

Cell. 1988 Jul 1;54(1):27-35. doi: 10.1016/0092-8674(88)90176-6.


The formation of a dynamic tubulovesicular membrane network that resembles the endoplasmic reticulum (ER) has been observed in extracts of cultured chick embryo fibroblasts (CEF cells) using video-enhanced differential interference contrast microscopy. Initially, membranes in the CEF extracts appeared amorphous and aggregated, but with time, membrane tubules moved out along stationary microtubules. The membrane tubules formed new branches on intersecting microtubules and fused with other branches to form a network of interconnected polygons. The tubulovesicular network was solubilized by detergent and took on a beaded morphology in a hypotonic buffer. Formation of the tubulovesicular network required ATP and microtubules. The network did not contain elements of the plasma membrane, Golgi apparatus, or mitochondria but could be labeled with ER markers. We suggest that the tubulovesicular network contains components from the ER and is formed by membrane associated motors moving upon microtubules in a process we call microtubule-dependent tethering.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / physiology
  • Animals
  • Cells, Cultured
  • Chick Embryo
  • Endoplasmic Reticulum / ultrastructure*
  • Fibroblasts
  • Fluorescent Antibody Technique
  • Freeze Etching
  • Freeze Fracturing
  • Microscopy, Electron
  • Microscopy, Interference
  • Microtubules / ultrastructure*
  • Models, Biological
  • Osmolar Concentration


  • Adenosine Triphosphate