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Evidence That Factor VIII Forms a Bivalent Complex with the Low Density Lipoprotein (LDL) Receptor-related Protein 1 (LRP1): IDENTIFICATION OF CLUSTER IV ON LRP1 AS THE MAJOR BINDING SITE.

ABSTRACT: Hemophilia A is a bleeding disorder caused by a deficiency in coagulation factor VIII (fVIII) that affects 1 in 5,000 males. Current prophylactic replacement therapy, although effective, is difficult to maintain due to the cost and frequency of injections. Hepatic clearance of fVIII is mediated by the LDL receptor-related protein 1 (LRP1), a member of the LDL receptor family. Although it is well established that fVIII binds LRP1, the molecular details of this interaction are unclear as most of the studies have been performed using fragments of fVIII and LRP1. In the current investigation, we examine the binding of intact fVIII to full-length LRP1 to gain insight into the molecular interaction. Chemical modification studies confirm the requirement for lysine residues in the interaction of fVIII with LRP1. Examination of the ionic strength dependence of the interaction of fVIII with LRP1 resulted in a Debye-Hückel plot with a slope of 1.8 ± 0.5, suggesting the involvement of two critical charged residues in the interaction of fVIII with LRP1. Kinetic studies utilizing surface plasmon resonance techniques reveal that the high affinity of fVIII for LRP1 results from avidity effects mediated by the interactions of two sites in fVIII with complementary sites on LRP1 to form a bivalent fVIII·LRP1 complex. Furthermore, although fVIII bound avidly to soluble forms of clusters II and IV from LRP1, only soluble cluster IV competed with the binding of fVIII to full-length LRP1, revealing that cluster IV represents the major fVIII binding site in LRP1.

SUBMITTER: Young PA

PROVIDER: S-EPMC5207074 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Evidence That Factor VIII Forms a Bivalent Complex with the Low Density Lipoprotein (LDL) Receptor-related Protein 1 (LRP1): IDENTIFICATION OF CLUSTER IV ON LRP1 AS THE MAJOR BINDING SITE.

Young Patricia A PA Migliorini Mary M Strickland Dudley K DK

The Journal of biological chemistry 20161029 50

Hemophilia A is a bleeding disorder caused by a deficiency in coagulation factor VIII (fVIII) that affects 1 in 5,000 males. Current prophylactic replacement therapy, although effective, is difficult to maintain due to the cost and frequency of injections. Hepatic clearance of fVIII is mediated by the LDL receptor-related protein 1 (LRP1), a member of the LDL receptor family. Although it is well established that fVIII binds LRP1, the molecular details of this interaction are unclear as most of t ...[more]

PMID: 27794518

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Project description:Low-density lipoprotein cholesterol (LDL-C) is the traditional measure of risk attributable to LDL. Non-high-density lipoprotein cholesterol (NHDL-C), apolipoprotein B (apoB), and LDL particle number (LDL-P) are alternative measures of LDL-related risk. However, the clinical utility of these measures may only become apparent among individuals for whom levels are inconsistent (discordant) with LDL-C.LDL-C was measured directly, NHDL-C was calculated, apoB was measured with immunoassay, and LDL-P was measured with nuclear magnetic resonance spectroscopy among 27 533 healthy women (median follow-up 17.2 years; 1070 incident coronary events). Participants were grouped by median LDL-C (121 mg/dL) and each of NHDL-C, apoB, and LDL-P. Discordance was defined as LDL-C greater than or equal to the median and the alternative measure less than the median, or vice versa. Despite high LDL-C correlations with NHDL-C, apoB, and LDL-P (r=0.910, 0.785, and 0.692; all P<0.0001), prevalence of LDL-C discordance as defined by median cut points was 11.6%, 18.9%, and 24.3% for NHDL-C, apoB, and LDL-P, respectively. Among women with LDL-C less than the median, coronary risk was underestimated for women with discordant (greater than or equal to the median) NHDL-C (age-adjusted hazard ratio, 2.92; 95% confidence interval, 2.33-3.67), apoB (2.48, 2.01-3.07), or LDL-P (2.32, 1.88-2.85) compared with women with concordant levels. Conversely, among women with LDL-C greater than or equal to the median, risk was overestimated for women with discordant (less than the median) NHDL-C (0.40, 0.29-0.57), apoB (0.34, 0.26-0.46), or LDL-P (0.42, 0.33-0.53). After multivariable adjustment for potentially mediating factors, including HDL cholesterol and triglycerides, coronary risk remained underestimated or overestimated by ?20% to 50% for women with discordant levels.For women with discordant LDL-related measures, coronary risk may be underestimated or overestimated when LDL-C alone is used.http://www.clinicaltrials.gov. Unique identifier: NCT00000479.

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Dataset Information

Evidence That Factor VIII Forms a Bivalent Complex with the Low Density Lipoprotein (LDL) Receptor-related Protein 1 (LRP1): IDENTIFICATION OF CLUSTER IV ON LRP1 AS THE MAJOR BINDING SITE.

Publications

Evidence That Factor VIII Forms a Bivalent Complex with the Low Density Lipoprotein (LDL) Receptor-related Protein 1 (LRP1): IDENTIFICATION OF CLUSTER IV ON LRP1 AS THE MAJOR BINDING SITE.

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