scholarly journals Interaction of high-molecular-weight kininogen with endothelial cell binding proteins suPAR, gC1qR and cytokeratin 1 determined by Surface Plasmon Resonance (BiaCore)

2011 ◽  
Vol 105 (06) ◽  
pp. 1053-1059 ◽  
Author(s):  
Berhane Ghebrehiwet ◽  
Kusumam Joseph ◽  
Alice Kao ◽  
Khalil Bdeir ◽  
Douglas Cines ◽  
...  

SummaryThe physiologic activation of the plasma kallikrein-kinin system requires the assembly of its constituents on a cell membrane. High-molecular-weight kininogen (HK) and cleaved HK (HKa) both interact with at least three endothelial cell binding proteins: urokinase plasminogen activator receptor (uPAR), globular C1q receptor (gC1qR,) and cytokeratin 1 (CK1). The affinity of HK and HKa for endothelial cells are KD=7–52 nM. The contribution of each protein is unknown. We examined the direct binding of HK and HKa to the soluble extracellular form of uPAR (suPAR), gC1qR and CK1 using surface plasmon resonance. Each binding protein linked to a CM-5 chip and the association, dissociation and KD (equilibrium constant) were measured. The interaction of HK and HKa with each binding protein was zinc-dependent. The affinity for HK and HKa was gC1qR>CK1>suPAR, indicating that gC1qR is dominant for binding. The affinity for HKa compared to HK was the same for gC1qR, 2.6-fold tighter for CK1 but 53-fold tighter for suPAR. Complex between binding proteins was only observed between gC1qR and CK1 indicating that a binary CK1-gC1qR complex can form independently of kininogen. Although suPAR has the weakest affinity of the three binding proteins, it is the only one that distinguished between HK and HKa. This finding indicates that uPAR may be a key membrane binding protein for differential binding and signalling between the cleaved and uncleaved forms of kininogen. The role of CK1 and gC1qR may be to initially bind HK to the membrane surface before productive cleavage to HKa.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2666-2666
Author(s):  
Ricardo G. Espinola ◽  
Robin A. Pixley ◽  
Berhane Ghebrehiwet ◽  
Kusumam Joseph ◽  
Alice Kuo ◽  
...  

Abstract The physiologic activation of the plasma kallikrein kinin system (KKS) requires the assembly of these proteins on the cell membrane. High molecular weight kininogen (HK) binds to endothelial cells through an interaction with a multiprotein receptor complex that consist of: urokinase plasminogen activator receptor (uPAR), globular C1q receptor (gC1qR) and cytokeratin 1 (CK1). The affinity of HK and cleaved HK (Hka) for endothelial cells is KD=7–52 nM but the affinity for each of the three binding proteins is unknown. We first examined the direct binding of HK and Hka to the soluble receptor form of uPAR (suPAR), gC1qR and CK1 using surface plasmon resonance (BiaCore). We linked suPAR, gC1qR and CK1 (800–1100 pg/mm2) by amine coupling to a CM-5 chip and perfused HK and Hka at a concentration ranging from 50 to 400 nM in the presence or absence of 10 μM ZnCl2. A Langmuir binding model with local fit (stoichiometry of 1:1) was used to analyse kon (association rate constant), koff (dissociation rate constant) and KD (equilibrium dissociation constant) for HK and Hka. HK Hka KD kon koff KD kon koff Immobilized Protein nM M-1s-1 x104 s-1 x10-4 nM M-1s-1 x104 s-1 x10-4 gC1qR 0.8±0.7 12.3±5.0 0.8±0.5 0.7±0.5 24.4±10.9 1.4±0.5 CK1 15.1±1.0 3.6±0.3 5.4±0.7 6.3±1.9 5.8±0.3 3.6±0.9 suPAR 2313.5±1465.3 1.0±0.7 164.8±22.2 43.6±16.6 21.3±11.9 78.5±10.6 The binding of HK and Hka to the three receptors was zinc dependent. The affinity for HK and Hka was gC1qR>CK1>suPAR. The high affinity for gC1qR and CK1 was similar for HK and Hka and was due to a very slow koff. The affinity for Hka compared to HK was 2.5-fold tighter for CK1 but 50-fold tighter for suPAR. A reversed immobiization was then performed. We immobilized HK, Hka and LK (800 pg/mm2) and suPAR, gC1qR and CK1 were flowed over the chip at a concentration ranging from 50 to 700 nM. Only gC1qR bound to immobilized HK and Hka, with a KD of 6.31± 2.8 pM for HK and 2.86±1.5 pM for Hka while the other 2 receptors did not bind. Receptor integrity was shown by preincubating HK or Hka with the pure receptors and observing competition with the immobilized receptors. Among the HK/Hka receptors, complex formation was only observed between gC1qR and immobiized CK1 with or without Hka indicating that a CK1-gC1qR complex can form independently of kininogen. This study indicates that although suPAR has the weakest affinity of the three receptors it is the only one that distinguishes between HK and Hka. Only one binary complex was revealed by this technique between CK1 and gC1qR. These results lay the foundation for anlayzing the affinity of these receptors in a cellular environment.


Blood ◽  
2000 ◽  
Vol 95 (2) ◽  
pp. 543-550 ◽  
Author(s):  
Robert W. Colman ◽  
Bradford A. Jameson ◽  
Yingzhang Lin ◽  
Donald Johnson ◽  
Shaker A. Mousa

We have demonstrated that high molecular weight kininogen (HK) binds specifically on endothelial cells to domain 2/3 of the urokinase receptor (uPAR). Inhibition by vitronectin suggests that kallikrein-cleaved HK (HKa) is antiadhesive. Plasma kallikrein bound to HK cleaves prourokinase to urokinase, initiating cell-associated fibrinolysis. We postulated that HK cell binding domains would inhibit angiogenesis. We found that recombinant domain 5 (D5) inhibited endothelial cell migration toward vitronectin 85% at 0.27 μM with an IC50 (concentration to yield 50% inhibition) = 0.12 μM. A D5 peptide, G486-K502, showed an IC50 = 0.2 μM, but a 25-mer peptide from a D3 cell binding domain only inhibited migration 10% at 139 μM (IC50 > 50 μM). D6 exhibited weaker inhibitory activity (IC50 = 0.50 μM). D5 also potently inhibited endothelial cell proliferation with an IC50 = 30 nM, while D3 and D6 were inactive. Using deletion mutants of D5, we localized the smallest region for full activity to H441-D474. To further map the active region, we created a molecular homology model of D5 and designed a series of peptides displaying surface loops. Peptide 440-455 was the most potent (IC50 = 100 nM) in inhibiting proliferation but did not inhibit migration. D5 inhibited angiogenesis stimulated by fibroblast growth factor FGF2 (97%) in a chicken chorioallantoic membrane assay at 270 nM, and peptide 400-455 was also inhibitory (79%). HK D5 (for which we suggest the designation, “kininostatin”) is a potent inhibitor of endothelial cell migration and proliferation in vitro and of angiogenesis in vivo.


2004 ◽  
Vol 91 (01) ◽  
pp. 61-70 ◽  
Author(s):  
Baby Tholanikunnel ◽  
Berhane Ghebrehiwet ◽  
Allen Kaplan ◽  
Kusumam Joseph

SummaryCell surface proteins reported to participate in the binding and activation of the plasma kinin-forming cascade includes gC1qR, cytokeratin 1 and u-PAR. Each of these proteins binds high molecular weight kininogen (HK) as well as Factor XII. The studies on the interaction of these proteins, using dot-blot analysis, revealed that cytokeratin 1 binds to both gC1qR and u-PAR while gC1qR and u-PAR do not bind to each other. The binding properties of these proteins were further analyzed by gel filtration. When biotinylated cytokeratin 1 was incubated with either gC1qR or u-PAR and gel filtered, a new, higher molecular weight peak containing biotin was observed indicating complex formation. The protein shift was also similar to the biotin shift. Further, immunoprecipitation of solubilized endothelial cell plasma membrane proteins with anti-gC1qR recovered both gC1qR and cytokeratin 1, but not u-PAR. Immunoprecipitation with anti-u-PAR recovered only u-PAR and cytokeratin 1. By competitive ELISA, gC1qR inhibits u-PAR from binding to cytokeratin 1; u-PAR inhibits gC1qR binding to a lesser extent and requires a 10-fold molar excess. Our data suggest that formation of HK (and Factor XII) binding sites along endothelial cell membranes consists of bimolecular complexes of gC1qR-cytokeratin 1 and u-PAR-cytokeratin 1, with gC1qR binding being favored.


2011 ◽  
Vol 94 (4) ◽  
pp. 1217-1226 ◽  
Author(s):  
Pathik Vyas ◽  
Anthony A O'kane ◽  
E Ager ◽  
S Crooks ◽  
C Elliott ◽  
...  

Abstract A collaborative study was conducted on an inhibition-based protein-binding assay using the Biacore Q™ biosensor instrument and the Biacore Qflex™ Kit Vitamin B12 PI. The samples studied included infant formula, cereals, premixes, vitamin tablets, dietary supplements, and baby food. The collaborative study, which involved 11 laboratories, demonstrated that the assay showed an RSDr of 1.59–27.8 and HorRat values for reproducibility of 0.34–1.89 in samples with levels ranging from ppm to ppb. The assay studied is a label-free protein binding-based assay that uses the principle of surface plasmon resonance (SPR) to measure the interaction between vitamin B12 and a specifc binding protein. A Biacore Q biosensor uses this principle to detect binding directly at the surface of a sensor chip with a hydrophilic gold-dextran surface. The instrument passes a mixture of prepared sample extract and binding protein solution across a covalently immobilized vitamin B12 chip surface, and the response is given as free-binding protein as the mixture binds to the immobilized surface. This technique uses the specifcity and robustness of the protein-ligand interaction to allow minimal sample preparation and a wide range of matrixes to be analyzed rapidly. The reagents and accessories needed to perform this assay are provided as the ready-to-use format “Qflex Kit Vitamin B12 PI.” The method is intended for routine use in the quantitative determination of vitamin B12 (as cyanocobalamin) in a wide range of food products, dietary vitamin supplements, and multivitamin premixes.


1987 ◽  
Author(s):  
Freek van Iwaarden ◽  
G Philip ◽  
de Groot ◽  
Bonno N Bouma

The presence of High Molecular Weight kininogen (HMWK) was demonstrated in cultured human endothelial cells (EC) by immunofluorescence techniques. Using an enzyme linked immunosorbent assay a concentration of 58 ng HMWK/10 cells was determined. Immunoprecipitation studies performed with lysed metabolically labelled endothelial cells and mono-specific antisera directed against HMWK suggested that HMWK is not synthesized by the endothelial cells. Endothelial cells cultured in the presence of HMWK-depleted serum did not contain HMWK. This, suggests that endothelial cells can internalize HMWK. Using 125I-HMWK it was demonstrated that cultured endothelial cells bind HMWK in a time-dependent, specific and saturable.way. The cells were found to internalize 125I-HMWK, since I-HMWK was detected in solubilized endothelial cells after the cell bound 125I-HMWK had been eluted with dextran sulphate.The binding of I-HMWK required the presence of zinc ions. Optimal binding of 125I-HMWK was observed at 50 μM Zn++ . Calcium ions inhibited the Zn++ dependent binding of 125I-HMWK |25EC. In the presence of 3 mM CaCl2 the total binding of 125I-HMWK was significantly decreased, and a .concentration of 200 μM Zn++ was Required for the binding of 125I-HMWK to thecells. Higher,. Ca concentrations did not further decrease the binding of 125I-HMWK. Analysis of tl^e binding data by the ligand computer program indicated 3.2 x 10 binding sites per cell for HMWK with a Kd of 35 nM at 50 μM ZnCl2 and 1 mM CaCl2. Specify binding of HMWK did also occur at physiological plasma Zn++ concentrations. Half maximal binding was observed at HMWK concentrations of ± 105 nM at 10 μM ZnCl2 and 45 nM at 25 μM ZnCl2. The HMWK binding sites were saturatecT at HMWK concentrations of 130 nM with 1.6 x 10 molecules of HMWK bound per cell and at 80 nM with 2.8 x 10 molecules of HMWK bound per cell at 10 and 25 pM ZnCl2 respectively. These results suggest that at physiological zinc, calcium and HMWK concentrations the HMWK binding sites on the endothelial cell are saturated. The presence of HMWK on the endothelial cell surface may play a role in the initiation of the intrinsic coagulation pathway. M ZnCl2 and 45 nM at 25 μM ZnCl2. The HMWK binding sites were saturatecT at HMWK concentrations of 130 nM with 1.6 x 10 molecules of HMWK bound per cell and at 80 nM with 2.8 x 10 molecules of HMWK bound per cell at 10 and 25 μM ZnCl2 respectively. These results suggest that at physiological zinc, calcium and HMWK concentrations the HMWK binding sites on the endothelial cell are saturated. The presence of HMWK on the endothelial cell surface may play a role in the initiation of the intrinsic coagulation pathway. M ZnCl2 and 45 nM at 25 μM ZnCl2. The HMWK binding sites were saturatecT at HMWK concentrations of 130 nM with 1.6 x 10 molecules of HMWK bound per cell and at 80 nM with 2.8 x 10 molecules of HMWK bound per cell at 10 and 25 μM ZnCl2 respectively. These results suggest that at physiological zinc, calcium and HMWK concentrations the HMWK binding sites on the endothelial cell are saturated. The presence of HMWK on the endothelial cell surface may play a role in the initiation of the intrinsic coagulation pathway. M ZnCl2 and 45 nM at 25 μM ZnCl2. The HMWK binding sites were saturatecT at HMWK concentrations of 130 nM with 1.6 x 10 molecules of HMWK bound per cell and at 80 nM with 2.8 x 10 molecules of HMWK bound per cell at 10 and 25 μM ZnCl2 respectively. These results suggest that at physiological zinc, calcium and HMWK concentrations the HMWK binding sites on the endothelial cell are saturated. The presence of HMWK on the endothelial cell surface may play a role in the initiation of the intrinsic coagulation pathway.M ZnCl2 and 45 nM at 25 μM ZnCl2. The HMWK binding sites were saturatecT at HMWK concentrations of 130 nM with 1.6 x 16 molecules of HMWK bound per cell and at 80 nM with 2.8 x 106 molecules of HMWK bound per cell at 10 and 25 μM ZnCl2 respectively. These results suggest that at physiological zinc, calcium and HMWK concentrations the HMWK binding sites on the endothelial cell are saturated. The presence of HMWK on the endothelial cell surface may play a role in the initiation of the intrinsic coagulation pathway.


2004 ◽  
Vol 19 (7) ◽  
pp. 653-660 ◽  
Author(s):  
Helen V Hsieh ◽  
Zachary A Pfeiffer ◽  
Terry J Amiss ◽  
Douglas B Sherman ◽  
J.Bruce Pitner

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