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Synthesis, Function, and Inactivation of Blood Coagulation Factor V.

Sørensen, Kristoffer LU (2005) In Doctoral dissertation series (Lund University, Faculty of Medicine) 2005:43.
Abstract
Blood coagulation factor V (FV) is a 330 kDa plasma glycoprotein. Activated FV (FVa) is a non-enzymatic cofactor to activated Factor X in the activation of prothrombin that occurs during coagulation.



To investigate the molecular mechanisms of the quantitative FV deficiency associated with the FV R2 haplotype (a common genetic variant in several populations), four missense mutations identified in the R2 haplotype allele were analysed by in vitro expression studies. The aparagine to glycine mutation at position 2194 was found to play a key role in the impaired secretion of the mutant FV by interfering with its transport from the endoplasmic reticulum to the Golgi complex.



FVa consists of a heavy (HC) and... (More)
Blood coagulation factor V (FV) is a 330 kDa plasma glycoprotein. Activated FV (FVa) is a non-enzymatic cofactor to activated Factor X in the activation of prothrombin that occurs during coagulation.



To investigate the molecular mechanisms of the quantitative FV deficiency associated with the FV R2 haplotype (a common genetic variant in several populations), four missense mutations identified in the R2 haplotype allele were analysed by in vitro expression studies. The aparagine to glycine mutation at position 2194 was found to play a key role in the impaired secretion of the mutant FV by interfering with its transport from the endoplasmic reticulum to the Golgi complex.



FVa consists of a heavy (HC) and a light chain (LC) associated in a divalent metal-ion dependent complex. Calcium ions bind to FVa, and we constructed a recombinant FV mutant to abolish calcium binding to a potential calcium-binding site in FVa in order to study the specific role of these residues in the expression of FVa activity. Following activation, the mutant rapidly lost FVa activity, and the HC and LC dissociated in agreement with what is expected of a FV molecule that cannot bind calcium ions.



We assessed the effect of heparin on FVa inactivation catalysed by activated protein C (APC). Heparin specifically inhibited the rapid phase of FVa inactivation (Arg506 cleavage). The inhibition was most likely caused by heparin binding to an electropositive cluster of amino acids in APC which normally interacts with a complementary electronegative region close to Arg506 in FVa. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Dr. Lane, David A., Department of Haematology, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus
organization
publishing date
type
Thesis
publication status
published
subject
keywords
activated protein C, heparin, calcium binding, R2 haplotype, Blood Coagulation, Factor V, Clinical chemistry, Klinisk kemi
in
Doctoral dissertation series (Lund University, Faculty of Medicine)
volume
2005:43
pages
181 pages
publisher
Department of Clinical Chemistry, Lund University
defense location
Jubileumsaulan, Medical Research Center, Malmö University Hospital, entrance 59.
defense date
2005-06-02 09:15
ISSN
1652-8220
ISBN
91-85439-49-5
language
English
LU publication?
yes
id
67f24d03-05fc-4caf-810b-ce99a9758109 (old id 24576)
date added to LUP
2007-06-01 07:38:04
date last changed
2016-09-19 08:44:56
@phdthesis{67f24d03-05fc-4caf-810b-ce99a9758109,
  abstract     = {Blood coagulation factor V (FV) is a 330 kDa plasma glycoprotein. Activated FV (FVa) is a non-enzymatic cofactor to activated Factor X in the activation of prothrombin that occurs during coagulation.<br/><br>
<br/><br>
To investigate the molecular mechanisms of the quantitative FV deficiency associated with the FV R2 haplotype (a common genetic variant in several populations), four missense mutations identified in the R2 haplotype allele were analysed by in vitro expression studies. The aparagine to glycine mutation at position 2194 was found to play a key role in the impaired secretion of the mutant FV by interfering with its transport from the endoplasmic reticulum to the Golgi complex.<br/><br>
<br/><br>
FVa consists of a heavy (HC) and a light chain (LC) associated in a divalent metal-ion dependent complex. Calcium ions bind to FVa, and we constructed a recombinant FV mutant to abolish calcium binding to a potential calcium-binding site in FVa in order to study the specific role of these residues in the expression of FVa activity. Following activation, the mutant rapidly lost FVa activity, and the HC and LC dissociated in agreement with what is expected of a FV molecule that cannot bind calcium ions.<br/><br>
<br/><br>
We assessed the effect of heparin on FVa inactivation catalysed by activated protein C (APC). Heparin specifically inhibited the rapid phase of FVa inactivation (Arg506 cleavage). The inhibition was most likely caused by heparin binding to an electropositive cluster of amino acids in APC which normally interacts with a complementary electronegative region close to Arg506 in FVa.},
  author       = {Sørensen, Kristoffer},
  isbn         = {91-85439-49-5},
  issn         = {1652-8220},
  keyword      = {activated protein C,heparin,calcium binding,R2 haplotype,Blood Coagulation,Factor V,Clinical chemistry,Klinisk kemi},
  language     = {eng},
  pages        = {181},
  publisher    = {Department of Clinical Chemistry, Lund University},
  school       = {Lund University},
  series       = {Doctoral dissertation series (Lund University, Faculty of Medicine)},
  title        = {Synthesis, Function, and Inactivation of Blood Coagulation Factor V.},
  volume       = {2005:43},
  year         = {2005},
}