Tissue factor encryption/de-encryption is not altered in the absence of the cytoplasmic domain

Thromb Haemost. 2000 Oct;84(4):657-63.


Since the cytoplasmic domain of tissue factor (TF) appears to have a role in TF function beyond coagulation, experiments were conducted to determine whether the cytoplasmic domain also has a role in regulating procoagulant activity of TF present in the cell membrane. TF encryption was quantitated in human YU-SITI, U87-MG, and mouse 3T3 cells which were transfected for expression of human tissue factor or a construct lacking the cytoplasmic domain (TF(CD)). Comparison of intact cells (encrypted) with fully disrupted cells (de-encrypted) showed that TF and TF(CD) were equally encrypted with respect to function in fX activation. Moreover, cells expressing TF and TF(CD) were indistinguishable in their procoagulant responses to A23187-calcium and varied concentrations of nonionic detergents. TF in membrane vesicles spontaneously shed by U87-MG cells was largely, but incompletely, de-encrypted, and the degree of de-encryption was independent of the cytoplasmic domain. We conclude that the predominant mechanism(s) for encrypting TF procoagulant activity is independent of the cytoplasmic domain.

Publication types

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

MeSH terms

  • Animals
  • Cell Line
  • Humans
  • Mice
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Structure-Activity Relationship
  • Thromboplastin / chemistry*
  • Thromboplastin / genetics
  • Thromboplastin / metabolism*
  • Transfection


  • Recombinant Proteins
  • Thromboplastin