scholarly journals Clathrin assembly involves a light chain-binding region.

1987 ◽  
Vol 105 (5) ◽  
pp. 2011-2019 ◽  
Author(s):  
G S Blank ◽  
F M Brodsky
Keyword(s):  
Monoclonal Antibodies ◽  
Binding Site ◽  
Heavy Chain ◽  
Light Chain ◽  
Intermediate Filament ◽  
Binding Sites ◽  
Light Chains ◽  
Binding Region ◽  
Intermediate Filament Proteins ◽  
Interaction Site

Two regions on the clathrin heavy chain that are involved in triskelion interactions during assembly have been localized on the triskelion structure. These regions were previously identified with anti-heavy chain monoclonal antibodies X19 and X35, which disrupt clathrin assembly (Blank, G. S., and F. M. Brodsky, 1986, EMBO (Eur. Mol. Biol. Organ.) J., 5:2087-2095). Antibody-binding sites were determined based on their reactivity with truncated triskelions, and were mapped to an 8-kD region in the middle of the proximal portion of the triskelion arm (X19) and a 6-kD region at the triskelion elbow (X35). The elbow site implicated in triskelion assembly was also shown to be included within a heavy chain region involved in binding the light chains and to constitute part of the light chain-binding site. We postulate that this region of the heavy chain binds to the interaction site identified on the light chains that has homology to intermediate filament proteins (Brodsky, F. M., C. J. Galloway, G. S. Blank, A. P. Jackson, H.-F. Seow, K. Drickamer, and P. Parham, 1987, Nature (Lond.), 326:203-205). These findings suggest the existence of a heavy chain site, near the triskelion elbow, which is involved in both intramolecular and intermolecular interactions during clathrin assembly.

scholarly journals Affinity labelling of the binding site of rabbit antibody. Evidence for the involvement of the hypervariable regions of the heavy chain

1974 ◽  
Vol 139 (1) ◽  
pp. 135-149 ◽  
Author(s):  
Christopher E. Fisher ◽  
Elizabeth M. Press
Keyword(s):  
Binding Site ◽  
Heavy Chain ◽  
Binding Sites ◽  
Light Chains ◽  
Rabbit Antibody ◽  
Heavy Chains ◽  
Group 4 ◽  
Hypervariable Regions ◽  
Affinity Labelling ◽  
Antibody Complex

The binding sites of rabbit antibodies with affinity for the haptenic group 4-azido-2-nitrophenyl-lysine have been specifically labelled by photolysis of the hapten–antibody complex. The extent of covalent labelling was 0.5–0.9mol of hapten bound/mol of antibody and, by using an immunoadsorbent, antibody with 1.3mol of hapten/mol was obtained. The antibody was specifically labelled in the binding site and the ratio of labelling of heavy and light chains was in the range 3.3–5.0. The labelled heavy chains were cleaved by CNBr treatment and after reduction and alkylation of the intrachain bonds, were digested with trypsin. Evidence is presented that two regions of the heavy chain, positions 29–34 and 95–114, together contain about 80% of the label on the heavy chain; these two regions respectively include two of the hypervariable regions of rabbit heavy chain.

Factor VIII Procoagulant Protein Interacts with Phospholipid Vesicles Via its 80 kDa Light Chain

1988 ◽  
Vol 60 (03) ◽  
pp. 442-446 ◽  
Author(s):  
G Kemball-Cook ◽  
S J Edwards ◽  
K Sewerin ◽  
L O Anderson ◽  
T W Barrowcliffe
Keyword(s):  
Factor Viii ◽  
Binding Site ◽  
Light Chain ◽  
Binding Sites ◽  
Light Chains ◽  
Phospholipid Vesicles ◽  
Polyacrylamide Gels ◽  
Phospholipid Binding

SummaryIn a previous report, we detailed the fractionation of polyclonal human anti-Factor VIII :C into a component directed exclusively against the phospholipid-binding site on Factor VIII (PL-site antibody) and another directed at other sites (non-PL-site antibody). The location on the F.VIII molecule of its PL-binding site has now been studied by two different methods using this fractionated 125I-labelled anti-F.VIII: C Fab’.The first method was modified from that of Weinstein et al. (Proc Natl Acad Sci USA 1981; 78: 5137-41), involving electrophoresis of F.VIII peptide-125I-Fab‘ A/F.VIII immunocomplexes in SDS-polyacrylamide gels. PL-site antibody reacted with F.VIII peptides of apparent Mr approximately 80 kDa and sometimes 160 kDa in plasma and concentrate, but not with larger peptides. Non-PL-site antibody, however, reacted with a range of peptides of apparent Mr 90 kDa to 280 kDa. In addition, when purified F.VIII containing heavy and light chains (HC + LC), and isolated LC peptides were analysed, PL-site antibody bound to LC peptides whereas non-PL-site antibody did not.The second method used the antibody pools in immunoradiometric assays (IRMA’s) of purified F.VIII peptides. Both labels measured similar amounts of F.VIII: Ag in a sample of purified F.VIII containing both HC and LC; on assaying an HC preparation, however, PL-site label measured only 2% of F.VIII: Ag found by non-PL-site label, indicating that PL-binding sites are absent in HC preparations.These results indicate that F.VIII binds to PL via its 80 kDa light chain.

scholarly journals Monoclonal antibodies against seven sites on the head and tail of Dictyostelium myosin.

1985 ◽  
Vol 100 (4) ◽  
pp. 1016-1023 ◽  
Author(s):  
G Peltz ◽  
J A Spudich ◽  
P Parham
Keyword(s):  
Monoclonal Antibodies ◽  
Atpase Activity ◽  
Heavy Chain ◽  
Light Chain ◽  
Binding Sites ◽  
Myosin Molecule ◽  
Dictyostelium Myosin ◽  
Antigenic Sites ◽  
Myosin Filaments ◽  
A Site

Ten monoclonal antibodies (My1-10) against Dictyostelium discoideum myosin were prepared and characterized. Nine bound to the 210-kD heavy chain and one (My8) bound to the 18-kD light chain. They defined six topographically distinct antigenic sites of the heavy chain. Five binding sites (the My1, My5, My10 site, and the My2, My3, My4, and My9 sites) are located on the rod portion of the myosin molecule. The position of the sixth site (the My6 and My7 site) is less certain, but it appears to be near the junction of the globular heads and the rod. Three of the antibodies (My2, My3, and My6) bound to myosin filaments in solution and could be sedimented in stoichiometric amounts with the filamentous myosin. In contrast, My4, which recognized a site on the rod, inhibited the polymerization of monomeric myosin into filaments. A single antibody (My6) affected the actin-activated ATPase of myosin. The nature of the effect depended on the valency of the antibody and the myosin. Bivalent IgG and F(ab')2 fragments of My6 inhibited the actin-activated ATPase of filamentous myosin by 50% whereas univalent Fab' fragments increased the activity by 50%. The actin-activated ATPase activity of the soluble chymotryptic fragment of myosin was increased 80-90% by both F(ab')2 and Fab' of My6.

scholarly journals Bradykinin regulates the expression of kininogen binding sites on endothelial cells

Blood ◽  
1993 ◽  
Vol 81 (11) ◽  
pp. 2936-2946 ◽  
Author(s):  
JM Zini ◽  
AH Schmaier ◽  
DB Cines
Keyword(s):  
Molecular Weight ◽  
Endothelial Cells ◽  
Binding Site ◽  
Heavy Chain ◽  
Light Chain ◽  
Binding Sites ◽  
Umbilical Vein ◽  
Single Class ◽  
Protein Kinase C Inhibitors ◽  
Molar Excess

The vasoactive compound bradykinin (BK) is liberated by proteolytic cleavage from high molecular weight kininogen (HK) and low molecular weight kininogen (LK). Expression of kininogens on cell surface receptors may affect the delivery of BK at sites of inflammation. Therefore, we investigated whether BK itself alters the expression of binding sites for its parent molecules, HK and LK, on the surface of cultured human umbilical vein endothelial cells (HUVEC). 125I-LK and 125I-HK each bind to a single class of sites on HUVEC in reactions that are saturable, reversible, and zinc-dependent (Bmax = 9.7 +/- 0.2 x 10(5) sites/cell; kd = 43.3 +/- 8 nmol/L; n = 5 and Bmax = 10.3 +/- 0.4 x 10(5) sites/cell; kd = 40.3 +/- 0.9 nmol/L; n = 3 for LK and HK, respectively). HK and LK compete for the same binding site (Ki = 19.4 +/- 5 nmol/L HK v 125I-LK; Ki = 24.5 +/- 4 nmol/L LK v 125I-HK, n = 3). Moreover, 50-fold molar excess light chain of HK inhibits 125I-LK binding 51% and 50-fold molar excess LK and the heavy chain of HK inhibit 125I-light chain of HK binding 92% and 76%, respectively. Preincubation of HUVEC with BK produces a transient, concentration- dependent increase in the binding of HK and LK, reaching a maximum 3 to 4 hours after addition of BK (46% increase over control for HK; 57% increase over control for LK; P < .005 for each ligand). Des-Arg9- bradykinin, a B1 receptor agonist, increases kininogen binding to the same extent as BK; the upregulation of kininogen binding sites by BK is partially blocked by a B1 but not by a B2 receptor antagonist. The protein kinase C inhibitors (PKC), sphingosine and H7, completely block the induction of HK receptors by BK. Phorbol 12-myristate 13-acetate (PMA), which also activates PKC, stimulates the binding of HK and the purified light chain of HK to HUVEC as well. However, unlike HK and its light chain, binding of LK and the heavy chain of HK are increased by PMA only in the presence of added calcium ion. These studies show that BK upregulates a common binding site for HK, LK, and each chain of HK on HUVEC. Induction of kininogen receptors on endothelial cells by BK may modulate the generation of this vasoactive compound at sites of vascular injury.

scholarly journals Study of Basic Local Alignment Search Tool (BLAST) and Multiple Sequence Alignment (Clustal- X) of Monoclonal mice/human antibodies

2021 ◽  
Author(s):  
IVAN VITO FERRARI ◽  
Paolo PATRIZIO
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Sequence Alignment ◽  
Heavy Chain ◽  
Light Chain ◽  
Light Chains ◽  
Local Alignment ◽  
Multiple Sequence ◽  
Heavy Chains ◽  
Search Tool

In this work, we have focused on the study of the Basic Local Alignment Search Tool (BLAST) and Multiple Sequence Alignment (Clustal- X) of different monoclonal mice antibodies to understand better the multiple alignments of sequences. Our strategy was to compare the light chains of multiple monoclonal antibodies to each other, calculating their identity percentage and in which amino acid portion. (See below figure 2) Subsequently, the same survey of heavy chains was carried out with the same methodology. (See below figure 3) Finally, sequence alignment between the light chain of one antibody and the heavy chain of another antibody was studied to understand what happens if chains are exchanged between antibodies. (See below figure 4) From our results of BLAST estimation alignment, we have reported that the Light Chains (Ls) of Monoclonal Antibodies in Comparison have a sequence Homology of about 60-80% and they have a part identical in sequence zone in range 100-210 residues amino acids, except ID PDB 4ISV, which it turns out to have a 40% lower homology than the others antibodies. As far as, the heavy chains (Hs) of Monoclonal Antibodies are concerned, however they tend to have a less homology of sequences, compared to lights chains consideration, equal to 60%-70% and they have an identical part in the sequence zone between 150-210 residues amino acids; with the exception of ID PDB 3I9G-3W9D antibodies that have an equal homology at 50%. ( See supporting part) Summing up: about 70-80% identity among 2 light chains of 2 antibodies, 60-70% identity between 2 heavy chains of 2 antibodies, 30% identity between the two chains of a antibody and 30% if you compare the light chain of one antibody with the heavy chain of another antibody.

scholarly journals The calpactin light chain is tightly linked to the cytoskeletal form of calpactin I: studies using monoclonal antibodies to calpactin subunits.

1987 ◽  
Vol 105 (5) ◽  
pp. 2111-2121 ◽  
Author(s):  
L Zokas ◽  
J R Glenney
Keyword(s):  
Monoclonal Antibodies ◽  
Heavy Chain ◽  
Light Chain ◽  
Human Fibroblasts ◽  
Cytoskeletal Proteins ◽  
Light Chains ◽  
Western Blots ◽  
Cultured Fibroblasts ◽  
Rous Sarcoma ◽  
Sarcoma Virus

Calpactins are a family of related Ca++-regulated cytoskeletal proteins. To analyze the expression and cytoskeletal association of calpactins we raised monoclonal antibodies with specificity for the heavy or light chains of calpactin I or to calpactin II. Comparison of the tissue distribution of calpactin I heavy and light chains by Western blots revealed that these subunits are coordinately expressed. Both soluble and cytoskeletal forms of the heavy chain of calpactin I were detected in human fibroblasts whereas only a soluble pool of calpactin II was found. These two forms of the calpactin I heavy chain differed both in their state of association with the light chain and in their rate of turnover. Both the soluble pool of the calpactin I heavy chain and calpactin II turned over three to four times faster than the cytoskeletal pool of heavy and light chains. Immunofluorescence microscopy revealed that the calpactin I light chain was present exclusively in the cytoskeleton whereas the calpactin I heavy chain distribution was more diffuse. No difference in the amount of light chain or the cytoskeletal attachment of phosphorylated calpactin I heavy chain was found in Rous sarcoma virus-transformed chick embryo fibroblasts compared with their normal counterpart. The antibody to the light chain of calpactin I was microinjected into cultured fibroblasts and kidney epithelial cells. In many cases antibody clustering was observed with the concomitant aggregation of the associated calpactin I heavy chain. The distribution of fodrin and calpactin II in injected cells remained unchanged. These results are consistent with the existence of two functionally distinct pools of calpactin I which differ in their association with the cytoskeleton.

scholarly journals Binding of Integrin α6β4 to Plectin Prevents Plectin Association with F-Actin but Does Not Interfere with Intermediate Filament Binding

1999 ◽  
Vol 147 (2) ◽  
pp. 417-434 ◽  
Author(s):  
Dirk Geerts ◽  
Lionel Fontao ◽  
Mirjam G. Nievers ◽  
Roel Q.J. Schaapveld ◽  
Patricia E. Purkis ◽  
...  
Keyword(s):  
Binding Site ◽  
Intermediate Filament ◽  
Binding Sites ◽  
Cytoplasmic Domain ◽  
Actin Binding ◽  
Yeast Two Hybrid ◽  
Dot Blot ◽  
Intermediate Filament Proteins ◽  
Two Hybrid

Hemidesmosomes are stable adhesion complexes in basal epithelial cells that provide a link between the intermediate filament network and the extracellular matrix. We have investigated the recruitment of plectin into hemidesmosomes by the α6β4 integrin and have shown that the cytoplasmic domain of the β4 subunit associates with an NH2-terminal fragment of plectin that contains the actin-binding domain (ABD). When expressed in immortalized plectin-deficient keratinocytes from human patients with epidermol- ysis bullosa (EB) simplex with muscular dystrophy (MD-EBS), this fragment is colocalized with α6β4 in basal hemidesmosome-like clusters or associated with F-actin in stress fibers or focal contacts. We used a yeast two-hybrid binding assay in combination with an in vitro dot blot overlay assay to demonstrate that β4 interacts directly with plectin, and identified a major plectin-binding site on the second fibronectin type III repeat of the β4 cytoplasmic domain. Mapping of the β4 and actin-binding sites on plectin showed that the binding sites overlap and are both located in the plectin ABD. Using an in vitro competition assay, we could show that β4 can compete out the plectin ABD fragment from its association with F-actin. The ability of β4 to prevent binding of F-actin to plectin explains why F-actin has never been found in association with hemidesmosomes, and provides a molecular mechanism for a switch in plectin localization from actin filaments to basal intermediate filament–anchoring hemidesmosomes when β4 is expressed. Finally, by mapping of the COOH-terminally located binding site for several different intermediate filament proteins on plectin using yeast two-hybrid assays and cell transfection experiments with MD-EBS keratinocytes, we confirm that plectin interacts with different cytoskeletal networks.

Are IgM Hevylite® Immunoglobulin Heavy Chain/Light Chain Analysis a Useful Tool to Differentiate IgM MGUS From Waldenström Macroglobulinemia?

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 5097-5097
Author(s):  
Ilda Murillo ◽  
Marcio M Andrade ◽  
Anel Montes ◽  
Jose M Grasa ◽  
Pilar Giraldo
Keyword(s):  
Binding Site ◽  
Heavy Chain ◽  
Light Chain ◽  
Prognostic Value ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
B Cell Lymphoma ◽  
Immunoglobulin Heavy Chain ◽  
Light Chains ◽  
Low Grade

Abstract Abstract 5097 Background: Monoclonal IgM is the biomarker that characterize to Waldenstrom's macroglobulinemia (WM), a rare low grade B-cell lymphoma derived of the lymphoplasmacytic cell, even serum IgM component also is presented in MGUS. Recently new determinations of heavy chain/light chain immunoglobulins pairs (HLC) have been developed as biomarkers to apply to every day clinical practice. The diagnostic and prognostic potential of these biomarkers is under investigation. The aim of this study is to present our experience in the use of free light chain assay (sFLC) and HLC as biomarkers at diagnostic in order to discriminate between MGUS and WM, and to evaluate their potential prognostic value during disease course. Patients and Methods: A total of 43 patients (pts) were detected as having a serum monoclonal IgM in the Hematology Department of MSUH. Pts were classified as MGUS or WM according to the morphological, immunophenotype characteristics of lymphoplasmacitic bone marrow cells and CT-scan data. Pts were examined every 3–6 months following our clinical protocol in order to detect progression or transformation. Serum samples were collected prior and during treatment and were kept frozen at −70°C since collection and incorporate to our regional Biobank. Analysis of IgM were performed with the sFLC, (Freelite® test, the Binding Site, Birmingham, UK) and the HLC (Hevylite® immunoassay the Binding Site). Freelite® test is a nephelometric measurement of kappa and lambda light chains that circulate not bound to immunoglobulin heavy chain. Hevylite® immunoassay is based on specific polyclonal antibodies that recognize epitopes spanning the junction of the heavy and light chains of the individual immunoglobulin isotypes, it measures specifically IgMkappa and IgMlambda, separately. A normal range of IgM Hevylite assay was produced from normal (blood donor) sera, median (CI 95%) were: IgMkappa, 0. 634 g/L (0. 29–1. 82); IgMlambda, 0. 42g/L (0. 17–0. 94); HLC ratio (HLCR), 1. 6 (0. 95–2. 3). For ease of comparison IgM HLCR was expressed as the involved monoclonal immunoglobulin (iHLC)/uninvolved polyclonal immunoglobulin (uHLC). Results: The study included a series of 25 WM, 18 IgM-MGUS (included 2 IgM-cryoglobulinemia), 36 at diagnosis and 7 at relapse/refractory. The median age was 67. 1 years (13–85); IgM HLCR was 114. 68 (1. 02 – 353) in WM symptomatic, 71. 55 (1. 02 – 286. 43) in WM asymptomatic and 9. 5 (0. 45 – 50. 74) in IgM MGUS (p=0. 003). HLCR was higher in WM patients requiring treatment (n=13) at diagnosis than in pts (n=30) not requiring treatment (113 v 15. 77 p=0. 019) and also HLCR was significantly higher at relapse/refractory (n=9) than in pts (n=34) not relapse (113 v 17. 17 p=0. 012) uHLC was significantly higher in IgM-MGUS than WM to IgMkappa (n=28) and IgMlambda (n=15) iHLC: 0. 37 g/L (0. 11–1. 25) v 0. 1 g/L (0. 02–4. 03), p=0. 022; and 0. 69 g/L (0. 08–4. 09) v 0. 32 g/L (0. 22–0. 63), p=0. 05 respectively. sFLC level was 64 mg/L (10. 88–993) in WM and 31. 7 mg/L (6. 08–141) in IgM MGUS (p=0. 05). sFLC level was higher in WM requiring treatment at diagnosis than in pts not requiring treatment (73. 7 v 36. 85 p=0. 039). sFLC level was not significative in relapse/refractory (p=0. 168), it was not separate between WM asymptomatic and WM symptomatic (p=0. 092). There was a good correlation between HLCR and sFLC ratio (r=0. 3, p=0. 044) but not with sFLC level, HLCR, sFLC level and sFLC ratio did not predict for overall survival (OS) and progression free survival (PFS) in our study. Mean estimated OS was 78. 3 months (95% CI: 53. 67–102. 94) and PFS 69. 7 months (95% CI: 47. 28–92. 13). Conclusion: It seems that HLCR and sFLC could be good biomarkers to differentiate between IgM-MGUS and WM at diagnostic. High levels of HLC and sFLC were also seen in pts requiring treatment. HLCR discriminates WM symptomatic/asymptomatic and progressing pts uHLC levels were significantly higher in IgM-MGUS than WM pts showing that IgM-MGUS have a more robust immune system. Further studies are needed to evaluate their prognostic value. This work has been partially sponsored by a grant from FEHHA Disclosures: No relevant conflicts of interest to declare.

scholarly journals Bradykinin regulates the expression of kininogen binding sites on endothelial cells

Blood ◽  
1993 ◽  
Vol 81 (11) ◽  
pp. 2936-2946 ◽  
Author(s):  
JM Zini ◽  
AH Schmaier ◽  
DB Cines
Keyword(s):  
Molecular Weight ◽  
Endothelial Cells ◽  
Binding Site ◽  
Heavy Chain ◽  
Light Chain ◽  
Binding Sites ◽  
Umbilical Vein ◽  
Single Class ◽  
Protein Kinase C Inhibitors ◽  
Molar Excess

Abstract The vasoactive compound bradykinin (BK) is liberated by proteolytic cleavage from high molecular weight kininogen (HK) and low molecular weight kininogen (LK). Expression of kininogens on cell surface receptors may affect the delivery of BK at sites of inflammation. Therefore, we investigated whether BK itself alters the expression of binding sites for its parent molecules, HK and LK, on the surface of cultured human umbilical vein endothelial cells (HUVEC). 125I-LK and 125I-HK each bind to a single class of sites on HUVEC in reactions that are saturable, reversible, and zinc-dependent (Bmax = 9.7 +/- 0.2 x 10(5) sites/cell; kd = 43.3 +/- 8 nmol/L; n = 5 and Bmax = 10.3 +/- 0.4 x 10(5) sites/cell; kd = 40.3 +/- 0.9 nmol/L; n = 3 for LK and HK, respectively). HK and LK compete for the same binding site (Ki = 19.4 +/- 5 nmol/L HK v 125I-LK; Ki = 24.5 +/- 4 nmol/L LK v 125I-HK, n = 3). Moreover, 50-fold molar excess light chain of HK inhibits 125I-LK binding 51% and 50-fold molar excess LK and the heavy chain of HK inhibit 125I-light chain of HK binding 92% and 76%, respectively. Preincubation of HUVEC with BK produces a transient, concentration- dependent increase in the binding of HK and LK, reaching a maximum 3 to 4 hours after addition of BK (46% increase over control for HK; 57% increase over control for LK; P < .005 for each ligand). Des-Arg9- bradykinin, a B1 receptor agonist, increases kininogen binding to the same extent as BK; the upregulation of kininogen binding sites by BK is partially blocked by a B1 but not by a B2 receptor antagonist. The protein kinase C inhibitors (PKC), sphingosine and H7, completely block the induction of HK receptors by BK. Phorbol 12-myristate 13-acetate (PMA), which also activates PKC, stimulates the binding of HK and the purified light chain of HK to HUVEC as well. However, unlike HK and its light chain, binding of LK and the heavy chain of HK are increased by PMA only in the presence of added calcium ion. These studies show that BK upregulates a common binding site for HK, LK, and each chain of HK on HUVEC. Induction of kininogen receptors on endothelial cells by BK may modulate the generation of this vasoactive compound at sites of vascular injury.

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