scholarly journals Infectivity and Arthritis Induction ofBorrelia japonicaon SCID Mice and Immune Competent Mice: Possible Role of Galactosylceramide Binding Activity on Initiation of Infection

1998 ◽  
Vol 42 (3) ◽  
pp. 171-175 ◽  
Author(s):  
Kazuhide Kaneda ◽  
Toshiyuki Masuzawa ◽  
Markus M. Simon ◽  
Emiko Isogai ◽  
Hiroshi Isogai ◽  
...  
Keyword(s):  
Binding Activity ◽  
Scid Mice ◽  
Arthritis Induction

scholarly journals Gastric Hyperplasia and Increased Proliferative Responses of Lymphocytes in Mice Lacking the COOH-terminal Ankyrin Domain of NF-κB2

1997 ◽  
Vol 186 (7) ◽  
pp. 999-1014 ◽  
Author(s):  
Hideaki Ishikawa ◽  
Daniel Carrasco ◽  
Estefania Claudio ◽  
Rolf-Peter Ryseck ◽  
Rodrigo Bravo
Keyword(s):  
T Cells ◽  
Lymphocyte Proliferation ◽  
Cytokine Production ◽  
Cell Types ◽  
Homozygous Deletion ◽  
Binding Activity ◽  
Activated T Cells ◽  
Physiological Relevance

The nfkb2 gene encodes the p100 precursor which produces the p52 protein after proteolytic cleavage of its COOH-terminal domain. Although the p52 product can act as an alternative subunit of NF-κB, the p100 precursor is believed to function as an inhibitor of Rel/NF-κB activity by cytoplasmic retention of Rel/NF-κB complexes, like other members of the IκB family. However, the physiological relevance of the p100 precursor as an IκB molecule has not been understood. To assess the role of the precursor in vivo, we generated, by gene targeting, mice lacking p100 but still containing a functional p52 protein. Mice with a homozygous deletion of the COOH-terminal ankyrin repeats of NF-κB2 (p100−/−) had marked gastric hyperplasia, resulting in early postnatal death. p100−/− animals also presented histopathological alterations of hematopoietic tissues, enlarged lymph nodes, increased lymphocyte proliferation in response to several stimuli, and enhanced cytokine production in activated T cells. Dramatic induction of nuclear κB–binding activity composed of p52-containing complexes was found in all tissues examined and also in stimulated lymphocytes. Thus, the p100 precursor is essential for the proper regulation of p52-containing Rel/NF-κB complexes in various cell types and its absence cannot be efficiently compensated for by other IκB proteins.

scholarly journals Colchicine-binding protein of the liver. Its characterization and relation to microtubules.

1975 ◽  
Vol 66 (3) ◽  
pp. 609-620 ◽  
Author(s):  
C Patzelt ◽  
A Singh ◽  
Y L Marchand ◽  
L Orci ◽  
B Jeanrenaud
Keyword(s):  
High Speed ◽  
Specific Binding ◽  
Electrophoretic Analysis ◽  
Binding Activity ◽  
Low Concentrations ◽  
Electrophoretic Behavior ◽  
High Affinity Binding Site ◽  
High Concentrations

Colchicine-binding activity of mouse liver high-speed supernate has been investigated. It has been found to be time and temperature dependent. Two binding activities with different affinities for colchicine seem to be present in this high-speed supernate, of which only the high-affinity binding site (half maximal binding at 5 x 10(-6) M colchicine) can be attributed to microtubular protein by comparison with purified tubulin. Vinblastine interacted with this binding activity by precipitating it when used at high concentrations (2 x 10(-3) M), and by stabilizing it at low concentrations (10(-5) M). Lumicolchicine was found not to compete with colchicine. The colchicine-binding activity was purified from liver and compared with that of microtubular protein from brain. The specific binding activity of the resulting preparation, its electrophoretic behavior, and the electron microscope appearance of the paracrystals obtained upon its precipitation with vinblastine permitted its identification as microtubular protein (tubulin). Electrophoretic analysis of the proteins from liver supernate that were precipitated by vinblastine indicated that this drug was not specific for liver tubulin. Preincubation of liver supernate with 5 mM EGTA resulted in a time-dependent decrease of colchicine-binding activity, which was partly reversed by the addition of Ca++. However, an in vitro formation of microtubules upon lowering the Ca++ concentration could not be detected. Finally, a method was developed enabling that portion of microtubular protein which was present as free tubulin to be measured and to be compared with the total amount of this protein in the tissue. This procedure permitted demonstration of the fact that, under normal conditions, only about 40% of the tubulin of the liver was assemled as microtubules. It is suggested that, in the liver, rapid polymerization and depolymerization of microtubules occur and may be an important facet of the functional role of the microtubular system.

scholarly journals Partial characterization of a binding site for von Willebrand factor on glycocalicin

Blood ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 19-26 ◽  
Author(s):  
AD Michelson ◽  
J Loscalzo ◽  
B Melnick ◽  
BS Coller ◽  
RI Handin
Keyword(s):  
Binding Site ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Binding Activity ◽  
Proteolytic Fragment ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Beta Galactosidase

The binding of von Willebrand factor (vWF) to platelet membrane glycoprotein Ib (GpIb) facilitates platelet adhesion to vascular subendothelium. In this study, we provide evidence that the vWF binding site is on glycocalicin (GC), a proteolytic fragment of GpIb, and we examine the role of the carbohydrate portion of GC on that binding. The binding to platelets of 6D1, a monoclonal antibody that recognizes an epitope on GpIb and blocks ristocetin-induced vWF binding to platelets, was inhibited by purified GC. In addition, purified GC inhibited ristocetin-dependent binding of 125I-labeled vWF to platelets. Since GC contains 60% carbohydrate by weight, we assessed the role of carbohydrate sequences on its interaction with antibody 6D1 and vWF. Based on the known sequence of the major oligosaccharide chain of GC--N- acetyl neuraminic acid, galactose, N-acetyl glucosamine, N-acetyl galactosamine--we treated GC sequentially with neuraminidase, beta- galactosidase, and beta-N-acetylglucosaminidase. Removal of sialic acid and galactose residues did not affect GC binding. Removal of N-acetyl glucosamine residues did not affect GC binding to 6D1 but did decrease the ability of GC to inhibit vWF binding to platelets, increasing the concentration needed to inhibit binding by 50% (IC50) 40-fold. This suggests that a portion of the oligosaccharide chains on GC contributes to the vWF binding activity of this molecule.

scholarly journals ROLE OF SERIN/ THREONINE KINASE INHIBITOR IN THERAPY NON-ALCOHOLIC STEATOHEPATITIS AND ALCOHOLIC HEPATITIS

2019 ◽  
Vol 6 (3) ◽  
pp. 101-109
Author(s):  
Novriantika Lestari
Keyword(s):  
Signal Transduction ◽  
Liver Fibrosis ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Binding Activity ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Receptor Binding Activity ◽  
Marked Accumulation

Liver fibrosis is a reversible response to a wound healing with marked accumulation of extracellular matrix which caused by injury to the liver. Liver fibrosis can be caused by various factors including alcohol and non-alcohol steatohepatitis. The process of fibrosis serves to localize the inflammation during chronic exposure. The hepatic stem cell (HSC) has a key role in the pathogenesis of liver fibrosis. The HSC activation is characterized by increased profibrogenic mediators including members of the TGF-? superfamily. In order to enable signal transduction, the mediator needs to bind to its receptors. The serine/ threonine kinase receptor is a receptor that binds to the TGF-? superfamily ligand, including TGF-?, BMP, activin and other mediators. The ligand receptor-binding activity will stimulate signal transduction that will translocate into the nucleus and phosphorylate various transcription factors that play a role in cell proliferation, differentiation, or apoptosis. There is currently no standard therapy for liver fibrosis. Based on the central role of the serine/ threonine kinase receptor in the pathogenesis of liver fibrosis, it is thought that the use of serine/ threonine kinase inhibitors is a promising therapy.

scholarly journals The Two ADF-H Domains of Twinfilin Play Functionally Distinct Roles in Interactions with Actin Monomers

2002 ◽  
Vol 13 (11) ◽  
pp. 3811-3821 ◽  
Author(s):  
Pauli J. Ojala ◽  
Ville O. Paavilainen ◽  
Maria K. Vartiainen ◽  
Roman Tuma ◽  
Alan G. Weeds ◽  
...  
Keyword(s):  
Binding Site ◽  
Binding Activity ◽  
Size Exclusion ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Monomer ◽  
Wild Type ◽  
Native Page ◽  
Exclusion Chromatography

Twinfilin is a ubiquitous and abundant actin monomer–binding protein that is composed of two ADF-H domains. To elucidate the role of twinfilin in actin dynamics, we examined the interactions of mouse twinfilin and its isolated ADF-H domains with G-actin. Wild-type twinfilin binds ADP-G-actin with higher affinity (K D = 0.05 μM) than ATP-G-actin (K D = 0.47 μM) under physiological ionic conditions and forms a relatively stable (k off = 1.8 s−1) complex with ADP-G-actin. Data from native PAGE and size exclusion chromatography coupled with light scattering suggest that twinfilin competes with ADF/cofilin for the high-affinity binding site on actin monomers, although at higher concentrations, twinfilin, cofilin, and actin may also form a ternary complex. By systematic deletion analysis, we show that the actin-binding activity is located entirely in the two ADF-H domains of twinfilin. Individually, these domains compete for the same binding site on actin, but the C-terminal ADF-H domain, which has >10-fold higher affinity for ADP-G-actin, is almost entirely responsible for the ability of twinfilin to increase the amount of monomeric actin in cosedimentation assays. Isolated ADF-H domains associate with ADP-G-actin with rapid second-order kinetics, whereas the association of wild-type twinfilin with G-actin exhibits kinetics consistent with a two-step binding process. These data suggest that the association with an actin monomer induces a first-order conformational change within the twinfilin molecule. On the basis of these results, we propose a kinetic model for the role of twinfilin in actin dynamics and its possible function in cells.

Sex-dependent liver colonization of human melanoma in SCID mice—role of host defense mechanisms

2012 ◽  
Vol 30 (4) ◽  
pp. 497-506 ◽  
Author(s):  
Judit Dobos ◽  
Anita Mohos ◽  
József Tóvári ◽  
Erzsébet Rásó ◽  
Tamás Lőrincz ◽  
...  
Keyword(s):  
Host Defense ◽  
Defense Mechanisms ◽  
Human Melanoma ◽  
Scid Mice

Differential specificity for binding of retinoblastoma binding protein 2 to RB, p107, and TATA-binding protein

1994 ◽  
Vol 14 (11) ◽  
pp. 7256-7264
Author(s):  
Y W Kim ◽  
G A Otterson ◽  
R A Kratzke ◽  
A B Coxon ◽  
F J Kaye
Keyword(s):  
Binding Site ◽  
Binding Protein ◽  
Tata Binding Protein ◽  
Binding Activity ◽  
Reversible Binding ◽  
Complex Interactions ◽  
Differential Binding ◽  
Cellular Transcription

The growth suppressor activities of the RB and p107 products are believed to be mediated by the reversible binding of a heterogeneous family of cellular proteins to a conserved T/E1A pocket domain that is present within both proteins. To study the functional role of these interactions, we examined the properties of cellular retinoblastoma binding protein 2 (RBP2) binding to RB, p107, and the related TATA-binding protein (TBP) product. We observed that although RBP2 bound exclusively to the T/E1A pocket of p107, it could interact with RB through independent T/E1A and non-T/E1A domains and with TBP only through the non-T/E1A domain. Consistent with this observation, we found that a mutation within the Leu-X-Cys-X-Glu motif of RBP2 resulted in loss of ability to precipitate p107, while RB- and TBP-binding activities were retained. We located the non-T/E1A binding site of RBP2 on a 15-kDa fragment that is independent from the Leu-X-Cys-X-Glu motif and encodes binding activity for RB and TBP but does not interact with p107. Despite the presence of a non-T/E1A binding site, however, recombinant RBP2 retained the ability to preferentially precipitate active hypophosphorylated RB from whole-cell lysates. In addition, we found that cotransfection of RBP2 can reverse in vivo RB-mediated suppression of E2F activity. These findings confirm the differential binding specificities of the related RB, p107, and TBP proteins and support the presence of multifunctional domains on the nuclear RBP2 product which may allow complex interactions with the cellular transcription machinery.

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