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    Rinku Majumder, PhD (she/her/hers)

    Professor
    Department of Interdisciplinary Oncology, LSUHSC
    New Orleans, Louisiana, United States

    Rinku Majumder, Ph.D, Professor of Biochemistry, LSU Health Science Center, New Orleans, LA,USA
    My research focuses on the anticoagulant Protein S (PS). PS is a vitamin K-dependent plasma glycoprotein. PS deficiency is one of several known risk factors for thrombophilia and PS deficiency can increase the risk of blood clots such as Deep Vein Thrombosis (DVT) and Pulmonary Embolism(PE). In severe cases of PS deficiency, soon after birth, infants develop a life-threatening blood clotting disorder called purpura fulminans. Despite 30 years of study of this important anticoagulant, the exact role of PS is still unknown. We identified a novel role of Protein S in regulating the clotting factors IXa and VIIIa independently of Activated Protein C (APC). Our publication in ATVB (cover page figure in October issue, 2012) demonstrated that regulation of thrombin generation via IXa/VIIIa is inhibited by Protein S. We were successful in identifying the amino acid residues in the HBE domain of FIXa which are responsible in binding PS. We identified a double mutant K132AR170A which was unable to bind to PS and produced a higher rate of fibrin formation than wild type FIXa in Hemophilia B mice. Recently, I began studying the regulation of PS regulation by obesity and use of contraceptive agents (OCA). Our Preliminary data showed that obesity and OCA reduce PS level drastically, leading to a dramatic increase in the risk of thrombosis. Currently, we are determining the molecular and biochemical mechanism for OCA- and obesity-induced suppression of PS level. Our paper in Blood (2018,132 (4): 452–455. ) showed for the first time that hypoxia downregulates PS expression. We plan to test, by various means, the hypothesis that the transcription factor HIF1α, which is active in obesity, and the estrogen receptor, which responds to estrogen, interact cooperatively with the PS to inhibit transcription.

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