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Functional analysis of the EGF-like domain mutations Pro55Ser and Pro55Leu, which cause mild hemophilia B.

Knobe, Karin LU ; Persson, Kristina LU ; Sjörin, Elsy LU ; Villoutreix, B O; Stenflo, Johan LU and Ljung, Rolf LU (2003) In Journal of Thrombosis and Haemostasis 1(4). p.782-790
Abstract
We studied the functional role of two mutations, Pro55Ser and Pro55Leu, located in the N-terminal Epidermal Growth Factor-like domain (EGF1) of coagulation factor (F) IX. Both mutations cause mild hemophilia B with habitual FIX coagulant activities of 10-12% and FIX antigen levels of 50%. We found that activation by FVIIa/TF and FXIa was normal for FIXPro55Ser, but resulted in proteolysis of FIXPro55Leu at Arg318-Ser319 with a concomitant loss of amidolytic activity, suggesting intramolecular communication between EGF1 and the serine protease domain in FIX. This was further supported by experiments using an anti-EGF1 monoclonal antibody. Activation of FX by FIXaPro55Ser was impaired in both the presence and the absence of phospholipid or... (More)
We studied the functional role of two mutations, Pro55Ser and Pro55Leu, located in the N-terminal Epidermal Growth Factor-like domain (EGF1) of coagulation factor (F) IX. Both mutations cause mild hemophilia B with habitual FIX coagulant activities of 10-12% and FIX antigen levels of 50%. We found that activation by FVIIa/TF and FXIa was normal for FIXPro55Ser, but resulted in proteolysis of FIXPro55Leu at Arg318-Ser319 with a concomitant loss of amidolytic activity, suggesting intramolecular communication between EGF1 and the serine protease domain in FIX. This was further supported by experiments using an anti-EGF1 monoclonal antibody. Activation of FX by FIXaPro55Ser was impaired in both the presence and the absence of phospholipid or FVIIIa, indicating that Pro55 is not directly involved in binding to FVIIIa. We also studied the effect of the two Pro55 mutations on Ca2+ affinity and found only small changes. Thus, the Pro55Ser mutation causes hemophilia primarily through to an impaired ability to activate FX whereas at least in vitro the Pro55Leu defect interferes with the activation of FIX. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Journal of Thrombosis and Haemostasis
volume
1
issue
4
pages
782 - 790
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • wos:000183062100029
  • pmid:12871416
  • scopus:0142166257
ISSN
1538-7933
DOI
language
English
LU publication?
yes
id
bbf44149-f40c-4d1f-8b12-b2b3d5650770 (old id 116792)
date added to LUP
2007-07-24 16:06:19
date last changed
2018-06-07 12:17:36
@article{bbf44149-f40c-4d1f-8b12-b2b3d5650770,
  abstract     = {We studied the functional role of two mutations, Pro55Ser and Pro55Leu, located in the N-terminal Epidermal Growth Factor-like domain (EGF1) of coagulation factor (F) IX. Both mutations cause mild hemophilia B with habitual FIX coagulant activities of 10-12% and FIX antigen levels of 50%. We found that activation by FVIIa/TF and FXIa was normal for FIXPro55Ser, but resulted in proteolysis of FIXPro55Leu at Arg318-Ser319 with a concomitant loss of amidolytic activity, suggesting intramolecular communication between EGF1 and the serine protease domain in FIX. This was further supported by experiments using an anti-EGF1 monoclonal antibody. Activation of FX by FIXaPro55Ser was impaired in both the presence and the absence of phospholipid or FVIIIa, indicating that Pro55 is not directly involved in binding to FVIIIa. We also studied the effect of the two Pro55 mutations on Ca2+ affinity and found only small changes. Thus, the Pro55Ser mutation causes hemophilia primarily through to an impaired ability to activate FX whereas at least in vitro the Pro55Leu defect interferes with the activation of FIX.},
  author       = {Knobe, Karin and Persson, Kristina and Sjörin, Elsy and Villoutreix, B O and Stenflo, Johan and Ljung, Rolf},
  issn         = {1538-7933},
  language     = {eng},
  number       = {4},
  pages        = {782--790},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Journal of Thrombosis and Haemostasis},
  title        = {Functional analysis of the EGF-like domain mutations Pro55Ser and Pro55Leu, which cause mild hemophilia B.},
  url          = {http://dx.doi.org/},
  volume       = {1},
  year         = {2003},
}