scholarly journals A high-affinity receptor for urokinase plasminogen activator on human keratinocytes: characterization and potential modulation during migration.

1990 ◽  
Vol 1 (11) ◽  
pp. 843-852 ◽  
Author(s):  
H McNeill ◽  
P J Jensen
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Plasminogen Activator ◽  
Binding Sites ◽  
Human Keratinocytes ◽  
Urokinase Plasminogen Activator ◽  
Receptor Expression ◽  
Epithelial Migration ◽  
High Affinity ◽  
Upa Receptor

Low passage cultures of normal human keratinocytes produce several components of the plasminogen activator/plasmin proteolytic cascade, including urokinase plasminogen activator (uPA), tissue plasminogen activator (tPA), and two specific inhibitors. Studies here presented demonstrate that these cells also contain a high-affinity (Kd = 3 x 10(-10) M) plasma membrane-binding site for uPA. High molecular weight uPA, either as the single-chain precursor or two-chain activated form, bound to the receptor; however, low molecular weight (33 kD) uPA, tPA, or epidermal growth factor did not compete for binding, demonstrating specificity. Acid treatment, which removed endogenous uPA from the receptor, was required to detect maximal binding (45,000 sites per cell). To investigate the possibility that the uPA receptor on keratinocytes may be involved in epithelial migration during wound repair, cultures were wounded and allowed to migrate into the wounded site. Binding sites for uPA were localized by autoradiographic analysis of 125I-uPA binding as well as by immunocytochemical studies using anti-uPA IgG. With both techniques uPA binding sites were detected selectively on the plasma membrane of cells at the leading edge of the migrating epithelial sheet. This localization pattern suggests that uPA receptor expression on keratinocytes may be coupled to cell migration during cutaneous wounding.

scholarly journals Interleukin 2 high-affinity receptor expression requires two distinct binding proteins.

1987 ◽  
Vol 165 (1) ◽  
pp. 223-238 ◽  
Author(s):  
K Teshigawara ◽  
H M Wang ◽  
K Kato ◽  
K A Smith
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Binding Sites ◽  
Binding Proteins ◽  
Lymphoblastic Leukemia ◽  
Interleukin 2 ◽  
Leukemia Cell ◽  
Receptor Expression ◽  
High Affinity ◽  
Antigen Protein

A cell line established from a patient with acute lymphoblastic leukemia was found to express IL-2 binding sites with a novel, intermediate affinity compared with the characteristic high-affinity IL-2-receptors and low-affinity IL-2 binding sites described previously. Clones were isolated from this cell line that displayed solely this new IL-2-binding protein, and were found to be unreactive with anti-Tac, the mAb that competes with IL-2 for binding. Moreover, these same cloned cells did not express mRNA detectable by hybridization with radiolabeled cDNA encoding the Tac protein. In contrast, the original cell line and similar clones expressed low levels of Tac mRNA and cell surface Tac antigen, both of which could be augmented by exposure to medium conditioned by adult T leukemia cell lines. Particularly noteworthy, induction of Tac antigen expression was paralleled by an increase in the number of high-affinity IL-2-R detectable. Since the expression of the Tac antigen protein by itself makes only for low-affinity IL-2 binding, these data prompted a reevaluation of the structural composition of high-affinity IL-2-R. Analysis of the IL-2-binding proteins expressed by leukemic cell lines lacking high-affinity receptors revealed only a single protein, larger than the Tac antigen protein (Mr = 75,000 vs. 55,000). In contrast, clones induced to express high-affinity receptors had clearly both of these IL-2-binding proteins. Moreover, when IL-2 binding to normal T cells was performed under conditions that favored the proportion of high-affinity receptors occupied, two distinct proteins identical to those already identified on the leukemic cells could be crosslinked covalently to radiolabeled IL-2. The interpretations derived from these varied, assembled data, point to two IL-2-binding proteins, both of which are required for high-affinity IL-2 binding.

scholarly journals The molecular-weight-dependence of the anti-coagulant activity of heparin

1978 ◽  
Vol 175 (2) ◽  
pp. 691-701 ◽  
Author(s):  
T C Laurent ◽  
A Tengblad ◽  
L Thunberg ◽  
M Höök ◽  
U Lindahl
Keyword(s):  
Molecular Weight ◽  
Binding Sites ◽  
Random Distribution ◽  
Degree Of Polymerization ◽  
Molecular Weight Range ◽  
High Affinity ◽  
Predicted Probability ◽  
Coagulant Activity ◽  
The Relationship ◽  
Molecular Weight Fractions

It is proposed that the anti-coagulant activity of heparin is related to the probability of finding, in a random distribution of different disaccharides, a dodecasaccharide with the sequence required for binding to antithrombin. It is shown that this probability is a function of the degree of polymerization of heparin. The hypothesis has been been tested with a series of narrow-molecular-weight-range fractions ranging from 5,600 to 36,000. The fractions having mol.wts. below 18,000 (comprising 85% of the original preparation) followed the predicted probability relationship as expressed by the proportion of molecules capable of binding to antithrombin. The probability that any randomly chosen dodecasaccharide sequence in heparin should bind to antithrombin was calculated to 0.022. The fraction with mol.wt. 36,000 contained proteoglycan link-region fragments, which may explain the deviation of the high-molecular-weight fractions from the hypothetical relationship. The relationship between anti-coagulant activity and molecular weight cannot be explained solely on the basis of availability of binding sites for antithrombin. The activity of high-affinity heparin (i.e. molecules containing high-affinity binding sites for antithrombin), determined either by a whole-blood clotting procedure or by thrombin inactivation in the presence of antithrombin, thus remained dependent on molecular weight. Possible explanations of this finding are discussed. One explanation could be a requirement for binding of thrombin to the heparin chain adjacent to antithrombin.

scholarly journals bcl-2Induction of Urokinase Plasminogen Activator Receptor Expression in Human Cancer Cells through Sp1 Activation

2003 ◽  
Vol 279 (8) ◽  
pp. 6737-6745 ◽  
Author(s):  
Daniela Trisciuoglio ◽  
Angela Iervolino ◽  
Antonio Candiloro ◽  
Gabriella Fibbi ◽  
Maurizio Fanciulli ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Plasminogen Activator ◽  
Human Cancer ◽  
Urokinase Plasminogen Activator ◽  
Receptor Expression ◽  
Urokinase Plasminogen Activator Receptor ◽  
Human Cancer Cells ◽  
Plasminogen Activator Receptor

scholarly journals Human high molecular weight kininogen binds to human umbilical vein endothelial cells via its heavy and light chains

Blood ◽  
1993 ◽  
Vol 81 (5) ◽  
pp. 1306-1311 ◽  
Author(s):  
SR Reddigari ◽  
P Kuna ◽  
G Miragliotta ◽  
Y Shibayama ◽  
K Nishikawa ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Endothelial Cells ◽  
Light Chain ◽  
Binding Sites ◽  
Umbilical Vein ◽  
Light Chains ◽  
Dependent Manner ◽  
High Molecular Weight Kininogen ◽  
High Affinity ◽  
Umbilical Vein Endothelial Cells

Abstract High molecular weight kininogen (HK) is a multifunctional plasma glycoprotein that occupies a critical position in pathways that link inflammation and coagulation. Excision of the vasoactive peptide bradykinin by plasma kallikrein results in kinin-free HK that consists of a 65-Kd N-terminal heavy chain (HK-HC) linked to the C-terminal 45- Kd light chain (HK-LC) by a disulfide bridge. HK-HC is an inhibitor of SH-proteases and HK-LC contains the binding sites for coagulation cofactors prekallikrein and factor XI. HK has previously been shown to bind specifically to human umbilical vein endothelial cells (HUVEC) in a zinc(2+)-dependent manner by a single class of high-affinity binding sites. We have further characterized that interaction in order to determine the cell-binding regions of HK. Competition binding experiments have indicated that either HK-LC or HK-HC was able to inhibit the binding of labeled HK with a 50% inhibitory concentration (IC50) of 77 nmol/L and 89 nmol/L, respectively. Cleaved two-chain HK (HKa) had an IC50 of 73 nmol/L, whereas uncleaved HK had an IC50 of 335 nmol/L. Direct binding experiments have indicated that HUVEC bind both purified [125I]HK-HC and [125I]HK-LC in a zinc(2+)-dependent manner and that HK-LC did not displace bound HK-HC. The light chain of low molecular weight kininogen or prekallikrein-binding region of HK did not inhibit the binding of HK to HUVEC. Our results, therefore, indicate that (1) HK is capable of binding to endothelial cells via both heavy and light chain moieties, (2) HKa has a higher affinity to HUVEC, and (3) purified heavy and light chains are capable of directly binding to HUVEC. The data are consistent with the presence of a single high-affinity site for HK on endothelial cells within which are subsites that bind to heavy and light chains.

scholarly journals Regulation of plasminogen activator in 3T3 cells: effect of phorbol myristate acetate on subcellular distribution and molecular weight.

1981 ◽  
Vol 90 (3) ◽  
pp. 727-731 ◽  
Author(s):  
S Jaken ◽  
P H Black
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Plasminogen Activator ◽  
Phorbol Myristate Acetate ◽  
Subcellular Distribution ◽  
Tumor Promoter ◽  
3T3 Cells ◽  
Myristate Acetate ◽  
Extracellular Release ◽  
Swiss 3T3

The tumor promoter, phorbol myristate acetate (PMA), stimulates plasminogen activator production and extracellular release in confluent Swiss 3T3 cells. Coordinated with the increased extracellular release is a redistribution of the activity into plasma membrane-enriched fractions and a shift in the predominant molecular weight species from 75,000 to 49,000 daltons. The evidence suggests that PMA induces the formation of the 49,000 dalton species which is preferentially located in plasma membrane-enriched fractions.

scholarly journals Competition between plasminogen and tissue plasminogen activator for cellular binding sites

Blood ◽  
1993 ◽  
Vol 82 (8) ◽  
pp. 2433-2441 ◽  
Author(s):  
J Felez ◽  
CJ Chanquia ◽  
P Fabregas ◽  
EF Plow ◽  
LA Miles
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Proteolytic Activity ◽  
Binding Sites ◽  
Cell Types ◽  
Receptor Expression ◽  
Plasminogen Activation ◽  
Single Chain ◽  
Cellular Receptors ◽  
Tissue Plasminogen

Cellular receptors for plasminogen and tissue plasminogen activator (t- PA) regulate plasminogen activation and cell-associated proteolytic activity. The characteristics of the interactions of both ligands with monocytes and monocytoid cell lines bear certain similarities, including affinity (kd approximately 1 mumol/L) capacity and susceptibility to carboxypeptidase treatment. Therefore, we have undertaken the present study to determine directly whether t-PA and plasminogen share common binding sites on cells. We found that recombinant human single-chain t-PA (rt-PA) could inhibit the binding of 125I-plasminogen to the cells and, conversely, plasminogen could inhibit 125I-rt-PA binding. This relationship was observed with 9 cell types, including both adherent cells and cells in suspension. In addition, under several conditions of cell treatment, plasminogen and t- PA receptor expression was modulated in parallel. Furthermore, molecules that have been implicated as candidate plasminogen receptors, gangliosides, and an alpha-enolase--related molecule, also interacted with t-PA. These results suggest that at least a component of the binding sites for plasminogen is shared with t-PA. Occupancy of these sites by either or both ligand(s) should result in arming the cells with the proteolytic activity of plasmin.

Sign in / Sign up

Export Citation Format

Share Document