[HTML][HTML] Phosphatidylethanolamine-phosphatidylserine binding synergy of seven coagulation factors revealed using Nanodisc arrays on silicon photonic sensors

SM Medfisch, EM Muehl, JH Morrissey, RC Bailey - Scientific Reports, 2020 - nature.com
SM Medfisch, EM Muehl, JH Morrissey, RC Bailey
Scientific Reports, 2020nature.com
Blood coagulation is regulated through protein–protein and protein–lipid interactions that
occur at the sub-endothelium following vascular damage. Soluble clotting proteins bind to
membrane components in a phosphatidylserine (PS) dependent manner to assemble multi-
protein complexes that regulate clot formation; however, PS is of limited abundance
physiologically. In this manuscript, we investigate synergy between PS and
phosphatidylethanolamine (PE)—a lipid of much higher abundance naturally. Using a label …
Abstract
Blood coagulation is regulated through protein–protein and protein–lipid interactions that occur at the sub-endothelium following vascular damage. Soluble clotting proteins bind to membrane components in a phosphatidylserine (PS) dependent manner to assemble multi-protein complexes that regulate clot formation; however, PS is of limited abundance physiologically. In this manuscript, we investigate synergy between PS and phosphatidylethanolamine (PE)—a lipid of much higher abundance naturally. Using a label-free, silicon photonic technology, we constructed arrays of Nanodiscs having variable lipid composition and probed the binding interactions of seven different clotting factors with GLA domains that have never been studied in tandem experiments before. The factors studied were prothrombin, activated factor VII, factor IX, factor X, activated protein C, protein S, and protein Z. Equilibrium dissociation constants (Kd) for each coagulation factor binding to Nanodiscs with unique compositions of PE and PS were determined. While all factors showed greater binding affinities in the presence of PS and PE, the most dramatic improvements in binding were observed when PS quantities were lowest. This demonstrates that synergy is effective in promoting coagulation factor binding under physiological lipid compositions, as opposed to the artificially high PS content probed in most in vitro activity studies.
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