Related Experiment Video
Updated: Aug 16, 2026

Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers
Published on: March 8, 2012
Prothrombinase assembly on an enveloped virus: evidence that the cytomegalovirus surface contains procoagulant
1Research Department, Canadian Red Cross Society, Ottawa.
Abstract:
In contrast to quiescent cells, we currently report that purified cytomegalovirus (CMV), strain AD169, constitutively expresses phosphatidylserine (PS)-like procoagulant activity. Initial evidence for this came from the observation of a CMV-dependent decrease in factor Xa clotting times. In a purified system, the assembly of a functional complex between factor Xa and the cofactor Va to form prothrombinase was found to be dependent on the addition of CMV. The corresponding dense bodies (DB) and noninfectious enveloped particles had similar activity. Quantification of the total virion and DB phospholipid, and comparison of prothrombin conversion rates to experiments conducted using known concentrations of PS-containing vesicles showed that 8.5% and 7.2% of the CMV and DB phospholipid, respectively is procoagulant. Direct binding studies of 125I-labeled factor Xa, active site-blocked factor Xa, or the zymogen factor X, with virions or DB showed a single class of Ca(2+)-dependent sites with dissociation constants in the order of 10(-7) MOL/l. Immunogold electron microscopy confirmed the specificity of the CMV/factor Xa association. Cumulatively, these data suggest that the CMV surface contains the necessary procoagulant phospholipid for coagulation enzyme complex assembly. This may enable CMV (and possibly other enveloped viruses) to bypass an important physiologic regulatory mechanism for the production of thrombin.
More Related Videos
08:10Production of High-Titer Infectious Influenza Pseudotyped Particles with Envelope Glycoproteins from Highly Pathogenic H5N1 and Avian H7N9 Viruses
Published on: January 15, 2020
09:08Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
Related Concept Videos
What are Viruses?
Viral Structure
Protein Complex Assembly
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Introduction to Virus
Coronavirus
Inhibitors of Virion Maturation and Assembly