title: Dengue virus nonstructural protein NS1 binds to prothrombin/thrombin and inhibits prothrombin activation.
abstract: OBJECTIVE
  Dengue virus (DENV) infection may result in severe dengue hemorrhage fever (DHF). However the mechanisms to cause hemorrhage during DENV infection are not fully understood. The sera level of secreted DENV nonstructural protein 1 (NS1) is correlated with the development of DHF. However, whether secreted NS1 can interfere with coagulation and contribute to the hemorrhage in DHF is unknown. Since thrombin plays a very important role in the activation of coagulation, we investigated whether NS1 can bind to thrombin and affect its formation or activity.
  
  
  RESULTS
  We first demonstrated that NS1 could bind to thrombin and formed NS1/thrombin complex in dengue patients' sera by enzyme-linked immunosorbent assay (ELISA). The ability of NS1 binding to prothrombin or thrombin was further confirmed using recombinant NS1 (rNS1) by ELISA, co-immunoprecipitation, and rNS1-affinity column purification. Even though the binding of rNS1 to thrombin showed no effect on thrombin activity, rNS1 could inhibit prothrombin activation and prolong activated partial thromboplastin time (APTT) of human platelet poor plasma.
  
  
  CONCLUSIONS
  These results suggest secreted DENV NS1 may bind to prothrombin and inhibit it activation, which in turn, may contribute to the APTT prolongation and hemorrhage in DHF patients.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan, ROC.
authors.forename: Shi-Wei
authors.initials: SW
authors.lastname: Lin
authors.forename: Yung-Chun
authors.initials: YC
authors.lastname: Chuang
authors.forename: Yee-Shin
authors.initials: YS
authors.lastname: Lin
authors.forename: Huan-Yao
authors.initials: HY
authors.lastname: Lei
authors.forename: Hsiao-Sheng
authors.initials: HS
authors.lastname: Liu
authors.forename: Trai-Ming
authors.initials: TM
authors.lastname: Yeh
mesh_terms: D000595:Amino Acid Sequence; D003715:Dengue / Q000378:metabolism; D003716:Dengue Virus / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000097:blood; D010314:Partial Thromboplastin Time; D011485:Protein Binding; D011516:Prothrombin / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D019595:Severe Dengue / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism*; D013918:Thrombin Time; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D046912:Multiprotein Complexes; C079340:NS1 protein, Dengue virus type 2; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; D011516:Prothrombin; D013917:Thrombin