Manjunath Goolyam Basavaraj, PhD
Novel strategies to enhance factor X (FX) activation through improved
factor VIIIa (FVIIIa) cofactor activity and stability
In order to design better treatment strategies for hemophilia, it is essential to understand the molecular interactions responsible for the assembly and function of intrinsic tenase complex. We recently discovered that exosite (secondary binding site) interactions play a predominant role in determining the affinity of FX for the Intrinsic tenase complex. By mapping FX binding exosite region, and understanding molecular mechanisms responsible for the exposure of exosite region in FVIIIa, it might be possible to enhance FXa formation.
Evidence suggest that FX binding exosite is most likely present within the a1-acidic region of FVIIIa (residues 337-372). By mapping exosite region residues and introducing gain-of-function mutation(s) it could be possible to achieve improved FVIIIa cofactor activity (Aim-1). Next, we hypothesize that cleavage at R372 in FVIII possibly expose FX binding exosite within the a1-acidic región of FVIIIa. However, this cleavage also results in spontaneous dissociation of A2-a2 subunit and rapid loss of FVIIIa cofactor activity. By blocking R372 cleavage and placing a linker between A1-a1 and A2-a2 subunits it is possible to explore the role of R372 cleavage on exposure of FX binding exosite, intrinsic tenase function and FVIIIa stability (Aim-2).
Dr. Manjunath Goolyam Basavaraj is currently a postdoctoral fellow at the Children's Hospital of Philadelphia Research Institute. He received his B.Sc. and M.Sc. degrees in Biochemistry from Sri Krishnadewaraya University, India, and his Ph.D. in Medical Biology from University of Tromsø, Norway. His Ph.D. thesis work focused on role of monocyte tissue factor and tissue factor pathway inhibitor in the pathophysiology of arterial and venous thrombosis. In December 2012, he joined the laboratory of Dr. Sriram Krishnaswamy in the Department of Pediatrics, Division of Hematology at the Children's Hospital of Philadelphia, a leading investigator in the biochemistry and enzymology of blood coagulation. Dr. Manjunath's research interests include- 1) Understanding molecular mechanisms responsible for highly regulated sequential activation of clotting factors during blood coagulation to develop better treatment strategies for bleeding disorders, and to discover potential antithrombotic drug targets, 2) Molecular basis for factor IX activation by tissue factor/factor VIIa complex, 3) Novel strategies to increase recombinant factor VIII and factor IX expression for therapy.
The Children's Hospital of Philadelphia,
Abramson Research Center,
3615 Civic Center Boulevard,
Philadelphia, PA 19104, USA.