ptFVa ( Pseudonaja Textilis Venom-Derived Factor Va) Retains Structural Integrity Following Proteolysis by Activated Protein C

Arteriosclerosis Thrombosis and Vascular Biology, vol. 41, pp. 2263–2276

Abstract

OBJECTIVE: The Australian snake venom ptFV (Pseudonaja textilis venom-derived factor V) variant retains cofactor function despite APC (activated protein C)-dependent proteolysis. Here, we aimed to unravel the mechanistic principles by determining the role of the absent Arg306 cleavage site that is required for the inactivation of FVa (mammalian factor Va). APPROACH AND RESULTS: Our findings show that in contrast to human FVa, APC-catalyzed proteolysis of ptFVa at Arg306 and Lys507 does not abrogate ptFVa cofactor function. Remarkably, the structural integrity of APC-proteolyzed ptFVa is maintained indicating that stable noncovalent interactions prevent A2-domain dissociation. Using Molecular Dynamics simulations, we uncovered key regions located in the A1 and A2 domain that may be at the basis of this remarkable characteristic. CONCLUSIONS: Taken together, we report a completely novel role for uniquely adapted regions in ptFVa that prevent A2 domain dissociation. As such, these results challenge our current understanding by which strict regulatory mechanisms control FVa activity.

Authors 6

1. Mark Schreuder Aachen Division of Thrombosis and Hemostasis Einthoven Laboratory for Vascular and Regenerative Medicine Einthoven Laboratory for Vascular and Regenerative Medicine

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.)

   Mark Schreuder https://orcid.org/0000-0003-2196-0943 Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.)

2. Xiaosong Liu

   Maastricht University

   Affiliation as printed

   Maastricht University, Department of Biochemistry, the Netherlands (X.L.)

3. Ka Lei Cheung Aachen Division of Thrombosis and Hemostasis Einthoven Laboratory for Vascular and Regenerative Medicine Ka Lei Cheung Division of Thrombosis and Hemostasis

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.)

   Ka Lei Cheung Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.)

4. Pieter H. Reitsma Aachen Division of Thrombosis and Hemostasis Einthoven Laboratory for Vascular and Regenerative Medicine Pieter H. Reitsma Division of Thrombosis and Hemostasis

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.)

   VarmX B.V, Leiden, the Netherlands (P.H.R.)

   Pieter H. Reitsma Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.). VarmX B.V, Leiden, the Netherlands (P.H.R.)

5. Gerry A. F. Nicolaes

   ORCID

   Affiliation as printed

   Gerry A.F. Nicolaes https://orcid.org/0000-0002-2482-0412

6. Mettine H.A. Bos Aachen Division of Thrombosis and Hemostasis Einthoven Laboratory for Vascular and Regenerative Medicine

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, the Netherlands (M.S., K.L.C., P.H.R., M.H.A.B.)