|
|
Blood, 1 October 2008, Vol. 112, No. 7, pp. 2795-2802.
Prepublished online as a Blood First Edition Paper on June 27, 2008; DOI 10.1182/blood-2008-02-138941.
 Previous Article | Next Article 
Submitted February 19, 2008
Accepted June 13, 2008
A phosphatidylserine binding site in factor Va C1 domain regulates both assembly and activity of the prothrombinase complex
Rinku Majumder, Mary Ann Quinn-Allen, William H Kane, and Barry R Lentz*
Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Medicine, Duke University, Durham, North Carolina, United States
* Corresponding author; email: uncbrl{at}med.unc.edu.
Tightly associated factor Va (FVa) and factor Xa (FXa) serve as the essential prothrombin-activating complex that assembles on phosphatidylserine (PS)-containing platelet membranes during blood coagulation. We have previously shown 1] that a soluble form of PS (C6PS) triggers assembly of a fully active FVa-FXa complex in solution and 2] that two molecules of C6PS bind to FVa light chain with one occupying a site in the C2 domain. We expressed human factor Va (rFVa) with mutations in either the C1-domain, (Y1956,L1957)A, the C2 domain, (W2063,W2064)A or both C-domains, (Y1956,L1957,W2063,W2064)A. Mutations in the C1 and C1-C2-domains of rFVa reduced the rate of activation of prothrombin to thrombin by FXa in the presence of 400 µM C6PS by 14,000-15,000 fold relative to either wild type or C2-mutant factor rFVa. The Kd's of FXa binding with rFVa (wild type, C2 mutant, C1 mutant, and C1C2 mutant) were 3, 4, 564, 624 nM respectively. Equilibrium dialysis experiments detected binding of 4, 3 and 2 molecules of C6PS to wild-type rFVa, C1-mutated, and C1C2-mutated rFVa, respectively. Since FVa heavy chain binds two molecules of C6PS, we conclude that both C2 and C1 domains bind one C6PS, with binding to the C1 domain regulating prothrombinase complex assembly.
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
M. H. A. Bos, M. Boltz, L. St. Pierre, P. P. Masci, J. de Jersey, M. F. Lavin, and R. M. Camire
Venom factor V from the common brown snake escapes hemostatic regulation through procoagulant adaptations
Blood,
July 16, 2009;
114(3):
686 - 692.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Oslakovic, M. J. Krisinger, A. Andersson, M. Jauhiainen, C. Ehnholm, and B. Dahlback
Anionic Phospholipids Lose Their Procoagulant Properties When Incorporated into High Density Lipoproteins
J. Biol. Chem.,
February 27, 2009;
284(9):
5896 - 5904.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
