The high molecular weight form of endothelial cell von Willebrand factor is released by the regulated pathway

Br J Haematol. 1991 Oct;79(2):239-45. doi: 10.1111/j.1365-2141.1991.tb04528.x.


We have previously reported that two forms of von Willebrand factor (vWf) exist in cultured human umbilical vein endothelial cells: a high molecular weight (HMW) form that is released and can be proteolytically cleaved into a series of plasma-like multimers, and a non-secreted low molecular weight (LMW) form. In this study, the mode of vWf release and the relationship between the two forms were examined. As determined by two-dimensional analysis as well as by immunoreactivity with an antibody to the propolypeptide, the LMW form of endothelial cell vWf consisted of a 260 kD pro-vWf polypeptide, while the HMW form consisted of a 225 kD mature polypeptide. Only the 260 kD polypeptide was susceptible to digestion with endoglycosidase H. Release of the HMW form into the culture media was accompanied by a decrease in cellular vWf. Treatment of endothelial cells with cycloheximide or tunicamycin caused a decrease in the LMW form but did not affect the secretion of the HMW form. These results suggest that two pools of vWf exist in endothelial cells--a LMW form of pro-vWf in the endoplasmic reticulum and a HMW form of mature vWf in the storage compartment. Released vWf derives only from the storage pool.

Publication types

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

MeSH terms

  • Cells, Cultured
  • Cycloheximide / pharmacology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Humans
  • Macromolecular Substances
  • Molecular Weight
  • Peptides / analysis
  • Tunicamycin / pharmacology
  • von Willebrand Factor / chemistry
  • von Willebrand Factor / metabolism*


  • Macromolecular Substances
  • Peptides
  • von Willebrand Factor
  • Tunicamycin
  • Cycloheximide