Role of the Low Density Lipoprotein-related Protein Receptor in Mediation of Factor VIII Catabolism

Abstract

In the present study, we found that catabolism of coagulation factor VIII (fVIII) is mediated by the low density lipoprotein receptor-related protein (LPR), a liver multiligand endocytic receptor. In a solid phase assay, fVIII was shown to bind to LRP (K d 116 nm). The specificity was confirmed by a complete inhibition of fVIII/LRP binding by 39-kDa receptor-associated protein (RAP), an antagonist of all LRP ligands. The region of fVIII involved in its binding to LRP was localized within the A2 domain residues 484–509, based on the ability of the isolated A2 domain and the synthetic A2 domain peptide 484–509 to prevent fVIII interaction with LRP. Since vWf did not inhibit fVIII binding to LRP, we proposed that LRP receptor may internalize fVIII from its complex with vWf. Consistent with this hypothesis, mouse embryonic fibroblasts that express LRP, but not fibroblasts genetically deficient in LRP, were able to catabolize 125I-fVIII complexed with vWf, which was not internalized by the cells. These processes could be inhibited by RAP and A2 subunit of fVIII, indicating that cellular internalization and degradation were mediated by interaction of the A2 domain of fVIII with LRP. In vivo studies of125I-fVIII·vWf complex clearance in mice demonstrated that RAP completely inhibited the fast phase of the biphasic125I-fVIII clearance that is responsible for removal of 60% of fVIII from circulation. Inhibition of the RAP-sensitive phase prolonged the half-life of 125I-fVIII in circulation by 3.3-fold, indicating that LRP receptor plays an important role in fVIII clearance. In the present study, we found that catabolism of coagulation factor VIII (fVIII) is mediated by the low density lipoprotein receptor-related protein (LPR), a liver multiligand endocytic receptor. In a solid phase assay, fVIII was shown to bind to LRP (K d 116 nm). The specificity was confirmed by a complete inhibition of fVIII/LRP binding by 39-kDa receptor-associated protein (RAP), an antagonist of all LRP ligands. The region of fVIII involved in its binding to LRP was localized within the A2 domain residues 484–509, based on the ability of the isolated A2 domain and the synthetic A2 domain peptide 484–509 to prevent fVIII interaction with LRP. Since vWf did not inhibit fVIII binding to LRP, we proposed that LRP receptor may internalize fVIII from its complex with vWf. Consistent with this hypothesis, mouse embryonic fibroblasts that express LRP, but not fibroblasts genetically deficient in LRP, were able to catabolize 125I-fVIII complexed with vWf, which was not internalized by the cells. These processes could be inhibited by RAP and A2 subunit of fVIII, indicating that cellular internalization and degradation were mediated by interaction of the A2 domain of fVIII with LRP. In vivo studies of125I-fVIII·vWf complex clearance in mice demonstrated that RAP completely inhibited the fast phase of the biphasic125I-fVIII clearance that is responsible for removal of 60% of fVIII from circulation. Inhibition of the RAP-sensitive phase prolonged the half-life of 125I-fVIII in circulation by 3.3-fold, indicating that LRP receptor plays an important role in fVIII clearance. factor VIII light chain of fVIII heavy chain of fVIII von Willebrand factor low density lipoprotein receptor-related protein/α2-macroglobulin receptor receptor associated protein mouse embryonic fibroblasts, expressing LRP on their surface fibroblasts, genetically deficient in LRP bovine serum albumin monoclonal antibody The plasma glycoprotein factor VIII (fVIII)1 functions as a cofactor for factor IXa in the factor X activation enzyme complex in the intrinsic pathway of blood coagulation, and its level is decreased or the protein is nonfunctional in patients with hemophilia A. The fVIII protein consists of a homologous A and C domains and a unique B domain which are arranged in the order A1-A2-B-A3-C1-C2 (1Vehar G.A. Keyt B. Eaton D. Rodrigues H. O'Brien D.P. Rotblat F. Opperman H. Keck R. Wood W.I. Harkins R.N. Tuddenham E.G.D. Lawn R.M. Capon D.J. Nature. 1984; 312: 337-340Crossref PubMed Scopus (658) Google Scholar). It is processed to a series of Me2+-linked heterodimers produced by cleavage at the B-A3 junction (2Fay P.J. Anderson M.T. Chavin S.I. Marder V.J. Biochim. Biophys. Acta. 1986; 871: 268-278Crossref PubMed Scopus (123) Google Scholar), generating a light chain (LCh) which consists of an acidic region and A3, C1, and C2 domains and a heavy chain (HCh) which consists of the A1, A2, and B domains (Fig. 1). Transplantational studies both in animals and humans demonstrated that liver hepatocytes are the major fVIII-producing cells (3Lewis J.H. Bontempo F.A. Spero J.A. Gorenc T.J. Ragni M.V. Starzl T.E. N. Engl. J. Med. 1985; 312: 1189-1190Crossref PubMed Scopus (116) Google Scholar, 4Bontempo F.A. Lewis J.H. Gorenc T.J. Spero J.A. Ragni M.V. Scott J.P. Starzl T.E. Blood. 1987; 69: 1721-1724Crossref PubMed Google Scholar). Immediately after release into circulation, fVIII binds with a high affinity (K d < 0.5 nm (5MacGregor I.R. McLaughlin L.F. MacGregor M.C. Prowse C.V. Pepper D.S. Vox. Sang. 1995; 69: 319-327Crossref PubMed Scopus (7) Google Scholar, 6Saenko E.L. Scandella D. J. Biol. Chem. 1997; 272: 18007-18014Abstract Full Text Full Text PDF PubMed Scopus (163) Google Scholar)) to its carrier protein vWf to form a tight, noncovalent complex. The binding to vWf is required for maintenance of a normal fVIII level in circulation, since vWf stabilizes association of the LCh and HCh (7Wise R.J. Dorner A.J. Krane M. Pittman D.D. Kaufman R.J. J. Biol. Chem. 1991; 266: 21948-21955Abstract Full Text PDF PubMed Google Scholar). This prevents fVIII from binding to phospholipid membranes (8Gilbert G.E. Drinkwater D. Barter S. Clouse S.B. J. Biol. Chem. 1992; 267: 15861-15868Abstract Full Text PDF PubMed Google Scholar), activation by factor Xa (9Koppelman S.J. Koedam J.A. van Wijnen M. Stern D.M. Nawroth P.P. Sixma J.J. Bouma B.N. J. Lab. Clin. Med. 1994; 123: 585-593PubMed Google Scholar), and protein C-catalyzed inactivation (10Fay P.J. Coumans J.-V. Walker F.J. J. Biol. Chem. 1991; 266: 2172-2177Abstract Full Text PDF PubMed Google Scholar). vWf comprises a series of high molecular mass, disulfide-bonded multimers with molecular mass values as high as 2 × 107 Da (11Hoyer L.W. Shainoff J.R. Blood. 1980; 55: 1056-1059Crossref PubMed Google Scholar) and circulates in plasma at 10 μg/ml or 50 nm assuming a molecular mass of 270 kDa for vWf monomers (12Girma J.-P. Chopek M.W. Titani K. Davie E.W. Biochemistry. 1986; 25: 3156-3163Crossref PubMed Scopus (64) Google Scholar). Since the concentration of fVIII in plasma is approximately 1 nm (13Wion K. Kelly D. Summerfield J.A. Tuddenham E.G.D. Lawn R.M. Nature. 1985; 317: 726-730Crossref PubMed Scopus (220) Google Scholar), one fVIII molecule is bound per 50 vWf monomers in plasma (14Vlot A.J. Koppelman S.J. van den Berg M.H. Bouma B.N. Sixma J.J. Blood. 1995; 85: 3150-3157Crossref PubMed Google Scholar). Activation of fVIII by thrombin leads to dissociation of activated fVIII (fVIIIa) from vWf and to at least 100-fold increase of the cofactor activity. The fVIIIa is a A1/A2/A3-C1-C2 heterotrimer (15Fay P.J. Haidaris P.J. Smudzin T.M. J. Biol. Chem. 1991; 266: 8957-8962Abstract Full Text PDF PubMed Google Scholar) in which domains A1 and A3 retain the metal ion linkage (Fig. 1). The stable dimer A1/A3-C1-C2 is weakly associated with the A2 subunit through electrostatic forces (15Fay P.J. Haidaris P.J. Smudzin T.M. J. Biol. Chem. 1991; 266: 8957-8962Abstract Full Text PDF PubMed Google Scholar). Spontaneous dissociation of the A2 subunit from the heterotrimer results in non-proteolytic inactivation of fVIIIa (15Fay P.J. Haidaris P.J. Smudzin T.M. J. Biol. Chem. 1991; 266: 8957-8962Abstract Full Text PDF PubMed Google Scholar). Infusion of fVIII·vWf complex, purified plasma, or recombinant fVIII into patients with severe hemophilia A who do not have fVIII (16Fijnvandraat K. Bertorp E. Ten Cate J.W. Johnsson H. Peters M. Savidge G. Tengborn L. Spira J. Stahl C. Thromb. Haemostasis. 1997; 77: 298-302Crossref PubMed Scopus (86) Google Scholar, 17Morfini M. Longo G. Messori A. Lee M. White G. Mannucci P. the Recombinate Study GroupThromb. Haemostasis. 1992; 68: 433-435Crossref PubMed Scopus (42) Google Scholar) or in normal individuals (18Over J. Sixma J.J. Bruine M.H. Trieschnigg M.C. Vlooswijk R.A. Bieser-Visser N.H. Bouma B.N. J. Clin. Invest. 1978; 62: 223-234Crossref PubMed Scopus (73) Google Scholar) results in a similar fVIII with a half-life of the complex fVIII and vWf is for the normal half-life and level of fVIII in circulation, the associated with of fVIII·vWf complex are not proposed that the fVIII·vWf complex is from plasma a clearance receptor and the this receptor is a low density protein receptor cellular was shown to be a of removal of a of involved in coagulation or These are of thrombin with cofactor J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), S.B. D.J. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar), and with A. B. M. M. J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar, K. E.L. J. S. A. 1992; PubMed Scopus Google Scholar), D. D.D. G. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar), factor pathway S. A. 1994; PubMed Scopus Google Scholar), and factor Xa M. J.P. Blood. PubMed Google Scholar, G. J.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). LRP, a glycoprotein to receptor S. M. J. Biol. Chem. Full Text PDF PubMed Google Scholar), is a of the low density lipoprotein receptor which the low density lipoprotein and glycoprotein receptor. LRP receptor consists of the J. S. H. J. Scopus Google Scholar) binding for LRP and the The of A in binding of M. A. L. J. J. Biol. Chem. Full Text PDF PubMed Google Scholar). The of may be responsible for of LRP and its ability to as a multiligand clearance receptor. In to the acidic region in LRP, its in residues Biochim. Biophys. Acta. 1994; PubMed Scopus Google Scholar). LRP is a major endocytic receptor in the liver J. G. 1992; PubMed Scopus Google Scholar) but in and and J. 1995; PubMed Scopus Google Scholar). A 39-kDa receptor-associated protein binds to LRP with high affinity (K d nm S. M. J. Biol. Chem. Full Text PDF PubMed Google Scholar)) and binding and internalization and degradation of all Biochim. Biophys. Acta. 1994; PubMed Scopus Google Scholar, J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar), as a for LRP is involved in of a In the present we demonstrated that fVIII binds to LRP, and that LRP the internalization and degradation of fVIII in fibroblasts and plays a role in the clearance of fVIII in found that interaction of the A2 domain of fVIII with LRP is responsible for catabolism of fVIII and localized the A2 domain region that is involved in the The monoclonal within the residues and were by and and by within A2 domain residues was as E.L. M. Scandella D. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). LRP was isolated from as K. J. Biol. PubMed Scopus Google Scholar). recombinant RAP was in and purified as J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar). was purified from of E.L. M. G.E. Scandella D. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). HCh and LCh were from fVIII as E.L. Scandella D. J. Biol. Chem. 1997; 272: 18007-18014Abstract Full Text Full Text PDF PubMed Scopus (163) Google Scholar). of the A1/A3-C1-C2 dimer and A2 subunit was ion of fVIII on a P.J. Haidaris P.J. J. Biol. Chem. Full Text PDF PubMed Google Scholar). A2 present in the A1/A3-C1-C2 was by its an in to vWf, fVIII, and A2 were into of fVIII in of were to of and of and for was by on a The of fVIII and A2 were and The in the P. P.J. PubMed Scopus Google Scholar) was similar to that of fVIII and were as J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar). were with purified LRP or in 50 for at and with in were with 125I-fVIII in in the or of fVIII, or for 1 at In the vWf, 125I-fVIII was in the in the of of vWf for at This was by of bound to the were from homologous and the P.J. D. 1980; PubMed Scopus Google Scholar). A normal mouse embryonic and a mouse embryonic that is genetically deficient in LRP were from of and as T.E. J. J. 1994; PubMed Google Scholar). were at 1 × and to bovine serum for at internalization and degradation were as H. J. Biol. Chem. 1995; PubMed Scopus Google Scholar). and degradation of the fVIII and A2 was after for at in 0.5 of binding of was as the of by of the cells by and in a J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar). This was shown to release bound to surface H. J. Biol. Chem. 1995; PubMed Scopus Google Scholar), a which associated with the cells after this was as was as in the that is in The of degradation was for mediated degradation by the of degradation in cells. to the vWf, and RAP were into The complex of fVIII with vWf was by of 125I-fVIII and vWf in the or of RAP for at mice were with of the through the of were from mouse into of at the and The were and the of plasma was and for of the blood The of in the circulation was the of the at 1 after as The of clearance for RAP concentration in the and was in mice and the of animals were liver and were and by the in The of 125I-fVIII clearance from circulation was a J. G. K. K. G. PubMed Scopus (42) Google Scholar), C is the of fVIII in plasma at a 1 2 are the to fast and of fVIII 1 and C 2 are of the fast and of for the concentration of RAP was a from 1 by the The values of C 2 were for clearance by C to 1 The ability of fVIII to bind to LRP in was in the homologous binding In the assay, binding of 125I-fVIII to purified LRP, but not to was inhibited by an of fVIII (Fig. 2 The fVIII interaction with LRP were from the homologous of 125I-fVIII by fVIII, which was by a a of with d of 116 fVIII in a complex with vWf is able to bind to LRP, we the of vWf binding to LRP. In this was with vWf as to complex to its to shown in 2 the binding of fVIII to LRP was not inhibited by of to nm vWf, which is its concentration in plasma This that the complex with vWf not fVIII ability to bind to LRP. an antagonist of completely inhibited the binding of 125I-fVIII to of nm (Fig. 2 the is similar to the affinity of RAP for LRP S. M. J. Biol. Chem. Full Text PDF PubMed Google Scholar). results fVIII binding to LRP. In order to the fVIII involved in interaction with LRP, the binding 125I-fVIII and LRP was by fVIII shown in HCh and A2 domains of fVIII, but not LCh or A1/A3-C1-C2 from LRP in the The values for HCh and A2 were and The of the d for fVIII binding to LRP and for inhibition of this binding by isolated A2 subunit that the A2 domain of HCh a major for fVIII binding to LRP. the region of the A2 domain responsible for interaction with LRP, we the of monoclonal with on fVIII/LRP A that within the A2 domain residues 484–509 E.L. L.W. Scandella D. P. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar)) but not within the A2 domain residues J.R. J. Clin. Invest. 1985; PubMed Scopus Google Scholar)) is able to the fVIII/LRP The concentration of required for inhibition of binding was The low of fVIII required for inhibition of fVIII/LRP binding is with a high affinity of for fVIII P. L.W. Scott Scandella D. J. Clin. Invest. 1994; PubMed Scopus (73) Google Scholar). Since was demonstrated that a synthetic peptide of A2 domain residues 484–509 E.L. L.W. Scandella D. P. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar), we residues are involved in binding to LRP. from the synthetic peptide 484–509, but not A2 peptide inhibited fVIII binding to LRP in a indicating that the region 484–509 of the A2 domain residues for fVIII binding to LRP. In the binding of 125I-fVIII to was in the of peptide 484–509 (Fig. Since the demonstrated a interaction fVIII and LRP, and vWf did not with this we that LRP may be of the cellular internalization from its complex with vWf. this hypothesis, the cellular and degradation were on which express LRP and on fibroblasts that are genetically deficient in LRP T.E. J. J. 1994; PubMed Google Scholar). The fVIII·vWf complex was by fVIII and vWf at their plasma of 1 and 50 shown in A and but not cells LRP, were of and 125I-fVIII in the of vWf. In internalization and degradation of 125I-fVIII by but not by fibroblasts was inhibited by an antagonist of binding to LRP. The ability of RAP to the and degradation of in cells and of cells to the and degradation that LRP is a of the degradation pathway of fVIII in we the of that on fVIII from the degradation is completely inhibited by cellular mediated of fVIII in the of vWf is mediated by LRP, we internalization and degradation of complex and (Fig. from A and both internalization and degradation of isolated 125I-fVIII by fibroblasts is approximately that in the of vWf. RAP inhibited internalization and degradation of 125I-fVIII to a of complex. In fibroblasts were able to internalize and isolated This that the pathway is not the of internalization and degradation of fVIII not complexed with vWf. vWf bound to fVIII is internalized and by we internalization and degradation vWf complexed with shown in and the of internalized and by both and cells were of the of 125I-fVIII from its complex with vWf the This that vWf not fVIII in the pathway and from fVIII at the of to of the complex into Since we demonstrated that the A2 subunit of fVIII is responsible for interaction of fVIII with purified LRP in we A2 is involved in internalization and degradation of fVIII·vWf complex by cells. A and that of the A2 subunit complex inhibited internalization after and degradation after of this complex. In the A1/A3-C1-C2 which did not inhibit fVIII interaction with purified LRP in the did not have and degradation by cells (Fig. LRP is of fVIII from its complex with vWf in the of RAP on the clearance of complex was in mouse In the mouse was with approximately 1 of 125I-fVIII J. G. K. K. G. PubMed Scopus (42) Google Scholar) complexed with vWf in the or of The of fVIII was similar to that to fVIII clearance in mice S. G. A. M. 1995; PubMed Scopus Google Scholar, S. R.M. A. M. Blood. PubMed Google Scholar). shown in RAP the half-life in mouse The of fVIII clearance in the of or RAP in the that RAP concentration of is and its increase not the fVIII clearance. In the of the concentration of RAP the half-life of 125I-fVIII was prolonged by approximately by In in the of was found in the liver but not in results that are with LRP in a high in J. G. 1992; PubMed Scopus Google Scholar). 125I-fVIII bound to vWf after into of mice plasma at were to fast protein as It was found that for the of to 125I-fVIII of the was as a in the of the as be for the fVIII·vWf complex, that 125I-fVIII bound to vWf in circulation in the of clearance In the of clearance of fVIII was a to the The results are with the of fast 1 and 2 of fVIII removal from the circulation. in the of a concentration of RAP the clearance could be by a a to that of the phase in the of Since the phase of clearance was not we all to 1 C and and a 2 from the of (Fig. the are the indicating that this the fVIII clearance The by the fVIII clearance are in The of RAP both the of the to the fast phase of fVIII and C the of fVIII by that In the of a of RAP 1 decreased by and C 1 decreased to RAP completely inhibited the fast phase of fVIII clearance of complexed with vWf from plasma of in a In the present we demonstrated that LRP the internalization and degradation of fVIII by cells and to fVIII clearance in This is based on we found that fVIII binds to purified LRP in and that this binding is by an antagonist of binding to LRP. fVIII is internalized and in mouse fibroblasts expressing LRP but not in mouse fibroblasts genetically deficient in LRP. RAP the cellular and degradation of 125I-fVIII from its complex with vWf by and clearance of 125I-fVIII from the circulation in mice be by the of on the that vWf did not inhibit fVIII binding to purified LRP, we that internalization of fVIII from its complex with vWf may be a of fVIII cells that express LRP, but not fibroblasts genetically deficient in LRP, were able to internalize and 125I-fVIII from its complex with vWf. These processes were inhibited by indicating that cellular internalization and degradation were mediated by interaction of fVIII with LRP. The of the was by in studies of complex in mice which demonstrated that RAP prolonged the half-life of 125I-fVIII in the circulation by 3.3-fold, indicating that a RAP-sensitive LRP, to the plasma clearance of found that fVIII clearance is a of fast and It is to that the fast phase of the clearance is since RAP inhibited this phase but not the the phase of fVIII clearance is not and the responsible for this pathway to be fVIII clearance in in the present study, is in with results of a in which fVIII clearance in mice was by the of J. G. K. K. G. PubMed Scopus (42) Google Scholar). The of fVIII clearance was demonstrated for P.J. C. Marder V.J. N. D. Thromb. 1986; Full Text PDF Scopus Google Scholar) and humans M. Longo G. Messori A. Lee M. White G. Mannucci P. the Recombinate Study GroupThromb. Haemostasis. 1992; 68: 433-435Crossref PubMed Scopus (42) Google Scholar). on we that the fast phase of fVIII clearance in humans is that inhibition of this pathway increase the half-life of fVIII by This be important for the of hemophilia A patients who fVIII to its level in circulation. This the of the of hemophilia A patients by the of to clearance of fVIII be to a fVIII in which the is localized the region 484–509 within the A2 domain of fVIII, which is responsible for fVIII binding to purified LRP. the from fVIII and activated fVIII were for inhibition of fVIII interaction with LRP. Since the A2 domain and which A2, were able to inhibit this interaction with we that A2 may be responsible for fVIII binding to LRP. of the region within the A2 domain was from that a monoclonal antibody with an within residues 484–509 completely inhibited fVIII interaction with LRP. the inhibition of fVIII/LRP binding by the synthetic peptide to residues 484–509 that this region of the A2 domain is to be involved in fVIII binding to LRP. The region 484–509 at and and at and residues in lipoprotein M.W. J. Biol. Chem. Full Text PDF PubMed Google Scholar), 1 complex P.J. C. Marder V.J. N. D. Thromb. 1986; Full Text PDF Scopus Google Scholar), and A. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, H. M.W. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar) were shown to be for electrostatic interaction with LRP. of the residues involved in binding to LRP in the leads to a of affinity for binding to LRP and L. J. PubMed Scopus Google Scholar) or complete A. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) inhibition of internalization and degradation of the of residues within the 484–509 region of fVIII may be a for of a recombinant fVIII with a of and a in circulation. found that internalization and degradation of isolated fVIII by cells was the processes for fVIII bound to vWf. catabolism of fVIII in the of vWf is with the demonstrated half-life of fVIII in patients with severe von Willebrand plasma vWf in with hemophilia A patients who have normal of vWf M. Mannucci P. Longo G. F. N. A. Thromb. PubMed Scopus Google Scholar, S. E. 1992; PubMed Scopus Google Scholar). the half-life of fVIII in von Willebrand patients was prolonged by the of vWf in the fVIII S. E. 1992; PubMed Scopus Google Scholar). The were as of fVIII complex with vWf and release of fVIII (7Wise R.J. Dorner A.J. Krane M. Pittman D.D. Kaufman R.J. J. Biol. Chem. 1991; 266: 21948-21955Abstract Full Text PDF PubMed Google Scholar, R.J. M.V. R.J. Dorner A.J. Biol. PubMed Scopus Google Scholar). that in to the vWf may the of fVIII clearance by the pathway and fVIII clearance to In the to fVIII interaction with LRP, P. van den Berg H. van J.A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) with fVIII binds to purified LRP with the affinity similar to that in RAP completely fVIII binding to purified LRP. cells fVIII and this is inhibited by In was shown the that HCh with the recombinant of LRP, J. and N. of A which are involved in LRP binding to M. A. L. J. J. Biol. Chem. Full Text PDF PubMed Google Scholar). based on LRP, P. van den Berg H. van J.A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) that the major fVIII region involved in binding to LRP is within LCh P. van den Berg H. van J.A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), in LCh to with fVIII for binding to LRP. to be of the within the isolated LCh is from that within the This was by P. van den Berg H. van J.A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), based on their that the association and dissociation for fVIII interaction with LRP from for LCh by P. van den Berg H. van J.A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), which a that the of the binding localized within the isolated LCh are not to within fVIII that the localized within the A2 domain in the present is to be the major responsible for fVIII interaction with LRP. In the that catabolism of fVIII an important pathway of fVIII clearance from circulation. are to for of the are to for of the and