A GPI-anchored co-receptor for tissue factor pathway inhibitor controls its intracellular trafficking and cell surface expression

S. A. Maroney, A. C. Cunningham, J. Ferrel, R. Hu, S. Haberichter, C. M. Mansbach, R. A. Brodsky, D. J. Dietzen, Alan E. Mast

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


Background: Tissue factor pathway inhibitor (TFPI) lacks a membrane attachment signal but it remains associated with the endothelial surface via its association with an, as yet, unidentified glycosyl phosphatidylinositol (GPI)-anchored coreceptor. Objectives/methods: Cellular trafficking of TFPI within aerolysin-resistant ECV304 and EA.hy926 cells, which do not express GPI-anchored proteins on their surface, was compared with their wild-type counterparts. Results and conclusions: Although aerolysin-resistant cells produce normal amounts of TFPI mRNA, TFPI is not expressed on the cell surface and total cellular TFPI is greatly decreased compared with wild-type cells. Additionally, normal, not increased, amounts of TFPI are secreted into conditioned media indicating that TFPI is degraded within the aerolysin-resistant cells. Confocal microscopy and studies using metabolic inhibitors demonstrate that aerolysin-resistant cells produce TFPI and transport it into the Golgi with subsequent degradation in lysosomes. The experimental results provide no evidence that cell surface FPI originates from secreted TFPI that binds back to aGPI-anchored protein. Instead, the data suggest that TFPI tightly, but reversibly, binds to a GPI anchored co-receptor in the ER/Golgi. The co-receptor then acts as a molecular chaperone for TFPI by trafficking it to the cell surface of wild-type cells or to lysosomes of aerolysin-resistant cells. TFPI that escapes co-receptor binding is secreted through the same pathway in both wild-type and aerolysin-resistant cells. The data provide a framework for understanding how TFPI is expressed on endothelium.

Original languageEnglish (US)
Pages (from-to)1114-1124
Number of pages11
JournalJournal of Thrombosis and Haemostasis
Issue number5
StatePublished - May 2006


  • Aerolysin
  • Endothelial cells
  • GPI-anchor
  • Tissue factor pathway inhibitor

ASJC Scopus subject areas

  • Hematology


Dive into the research topics of 'A GPI-anchored co-receptor for tissue factor pathway inhibitor controls its intracellular trafficking and cell surface expression'. Together they form a unique fingerprint.

Cite this