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Effects of factor Xa and protein S on the individual activated protein C-mediated cleavages of coagulation factor Va.

Norström, Eva LU ; Tran, Sinh LU ; Steen, Mårten LU and Dahlbäck, Björn LU (2006) In Journal of Biological Chemistry 281(42). p.31486-31494
Abstract
Activated protein C inhibits the procoagulant function of activated factor V (FVa) through proteolytic cleavages at Arg-306, Arg-506, and Arg-679. The cleavage at Arg-506 is kinetically favored but protected by factor Xa (FXa). Protein S has been suggested to annihilate the inhibitory effect of FXa, a proposal that has been challenged. To elucidate the effects of FXa and protein S on the individual cleavage sites of FVa, we used recombinant FVa:Q306/Q679 and FVa: Q506/Q679 variants, which can only be cleaved at Arg-506 and Arg-306, respectively. In the presence of active site blocked FXa (FXa-1.5-dansyl-GluGly-Arg), the FVa inactivation was followed over time, and apparent second order rate constants were calculated. Consistent with... (More)
Activated protein C inhibits the procoagulant function of activated factor V (FVa) through proteolytic cleavages at Arg-306, Arg-506, and Arg-679. The cleavage at Arg-506 is kinetically favored but protected by factor Xa (FXa). Protein S has been suggested to annihilate the inhibitory effect of FXa, a proposal that has been challenged. To elucidate the effects of FXa and protein S on the individual cleavage sites of FVa, we used recombinant FVa:Q306/Q679 and FVa: Q506/Q679 variants, which can only be cleaved at Arg-506 and Arg-306, respectively. In the presence of active site blocked FXa (FXa-1.5-dansyl-GluGly-Arg), the FVa inactivation was followed over time, and apparent second order rate constants were calculated. Consistent with results on record, we observed that FXa-1.5-dansylGlu-Gly- Arg decreased the Arg-506 cleavage by 20-fold, with a half-maximum inhibition of similar to 2 nM. Interestingly and in contrast to the inhibitory effect of FXa on the 506 cleavage, FXa stimulated the Arg-306 cleavage. Protein S counteracted the inhibition by FXa of the Arg-506 cleavage, whereas protein S and FXa yielded additive stimulatory effect of the cleavage at Arg-306. This suggests that FXa and protein S interact with distinct sites on FVa, which is consistent with the observed lack of inhibitory effect on FXa binding to FVa by protein S. We propose that the apparent annihilation of the FXa protection of the Arg-506 cleavage by protein S is due to an enhanced rate of Arg-506 cleavage of FVa not bound to FXa, resulting in depletion of free FVa and dissociation of FXa-FVa complexes. (Less)
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; ; and
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type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
281
issue
42
pages
31486 - 31494
publisher
ASBMB
external identifiers
  • wos:000241235300033
  • scopus:33845974902
ISSN
1083-351X
DOI
10.1074/jbc.M606441200
language
English
LU publication?
yes
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9a916881-ea45-4c83-937d-096c0872aed8 (old id 159867)
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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=16935856&dopt=Abstract
date added to LUP
2016-04-01 12:19:17
date last changed
2021-02-17 07:22:03
@article{9a916881-ea45-4c83-937d-096c0872aed8,
  abstract     = {Activated protein C inhibits the procoagulant function of activated factor V (FVa) through proteolytic cleavages at Arg-306, Arg-506, and Arg-679. The cleavage at Arg-506 is kinetically favored but protected by factor Xa (FXa). Protein S has been suggested to annihilate the inhibitory effect of FXa, a proposal that has been challenged. To elucidate the effects of FXa and protein S on the individual cleavage sites of FVa, we used recombinant FVa:Q306/Q679 and FVa: Q506/Q679 variants, which can only be cleaved at Arg-506 and Arg-306, respectively. In the presence of active site blocked FXa (FXa-1.5-dansyl-GluGly-Arg), the FVa inactivation was followed over time, and apparent second order rate constants were calculated. Consistent with results on record, we observed that FXa-1.5-dansylGlu-Gly- Arg decreased the Arg-506 cleavage by 20-fold, with a half-maximum inhibition of similar to 2 nM. Interestingly and in contrast to the inhibitory effect of FXa on the 506 cleavage, FXa stimulated the Arg-306 cleavage. Protein S counteracted the inhibition by FXa of the Arg-506 cleavage, whereas protein S and FXa yielded additive stimulatory effect of the cleavage at Arg-306. This suggests that FXa and protein S interact with distinct sites on FVa, which is consistent with the observed lack of inhibitory effect on FXa binding to FVa by protein S. We propose that the apparent annihilation of the FXa protection of the Arg-506 cleavage by protein S is due to an enhanced rate of Arg-506 cleavage of FVa not bound to FXa, resulting in depletion of free FVa and dissociation of FXa-FVa complexes.},
  author       = {Norström, Eva and Tran, Sinh and Steen, Mårten and Dahlbäck, Björn},
  issn         = {1083-351X},
  language     = {eng},
  number       = {42},
  pages        = {31486--31494},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Effects of factor Xa and protein S on the individual activated protein C-mediated cleavages of coagulation factor Va.},
  url          = {https://lup.lub.lu.se/search/files/2875128/625539.pdf},
  doi          = {10.1074/jbc.M606441200},
  volume       = {281},
  year         = {2006},
}