Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Botrocetin is a snake venom protein that enhances the affinity of the A1 domain of plasma von Willebrand factor (vWF) for the platelet receptor glycoprotein Ibalpha (GPIbalpha), an event that contributes to bleeding and host death. Here we describe a kinetic and crystallographic analysis of this interaction that reveals a novel mechanism of affinity enhancement. Using high-temporal-resolution microscopy, we show that botrocetin decreases the GPIbalpha off-rate two-fold in both human and mouse complexes without affecting the on-rate. The key to this behavior is that, upon binding of GPIbalpha to vWF-A1, botrocetin prebound to vWF-A1 makes no contacts initially with GPIbalpha, but subsequently slides around the A1 surface to form a new interface. This two-step mechanism and flexible coupling may prevent adverse alterations in on-rate of GPIbalpha for vWF-A1, and permit adaptation to structural differences in GPIbalpha and vWF in several prey species.
Nat Struct Mol Biol 2005 Feb
PMID:The snake venom protein botrocetin acts as a biological brace to promote dysfunctional platelet aggregation. 1566 69

Diabetes mellitus leads to endothelium dysfunction and an accelerated progression of atherosclerosis. Vascular complications of diabetes mellitus can affect not only large and medium arteries resulting in coronary heart disease and peripheral arteries diseases, but also small vessels leading to retinopathy and nephropathy. Intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), E-selectin and von Willebrand factor (vWF) are considered as markers of endothelium dysfunction. The aim of our study was to evaluate plasma levels of ICAM-1, VCAM-1, E-selectin and vWF in patients with type 2 diabetes mellitus receiving insulin therapy and who had diabetic non-proliferative retinopathy, proliferative retinopathy, or did not develop diabetic retinopathy. There were no statistically significant differences between studied groups in any of evaluated endothelium dysfunction markers. There was no statistically significant correlation between measured parameters and a period of diabetic history. None of the studied markers presented a significant correlation with a period of insulin treatment.
Int J Mol Med 2005 Mar
PMID:Endothelium dysfunction markers in patients with diabetic retinopathy. 1570 38

We have identified a new protein kinase in Dictyostelium discoideum that carries the same conserved class of "alpha-kinase" catalytic domain as reported previously in myosin heavy chain kinases (MHCKs) in this amoeba but that has a completely novel domain organization. The protein contains an N-terminal von Willebrand factor A (vWFA)-like motif and is therefore named VwkA. Manipulation of VwkA expression level via high copy number plasmids (VwkA++ cells) or gene disruption (vwkA null cells) results in an array of cellular defects, including impaired growth and multinucleation in suspension culture, impaired development, and alterations in myosin II abundance and assembly. Despite sequence similarity to MHCKs, the purified protein failed to phosphorylate myosin II in vitro. Autophosphorylation activity, however, was enhanced by calcium/calmodulin, and the enzyme can be precipitated from cellular lysates with calmodulin-agarose, suggesting that VwkA may directly bind calmodulin. VwkA is cytosolic in distribution but enriched on the membranes of the contractile vacuole and Golgi-like structures in the cell. We propose that VwkA likely acts indirectly to influence myosin II abundance and assembly behavior and possibly has broader roles than previously characterized alpha kinases in this organism, which all seem to be MHCKs.
Mol Biol Cell 2005 May
PMID:Identification and characterization of a novel alpha-kinase with a von Willebrand factor A-like motif localized to the contractile vacuole and Golgi complex in Dictyostelium discoideum. 1572 26

DAND1 (NBL1), DAND2 (CKTSF1B1 or GREM1 or GREMLIN), DAND3 (CKTSF1B2 or GREM2 or PRDC), DAND4 (CER1), DAND5 (CKTSF1B3 or GREM3 or DANTE), MUC2, MUC5AC, MUC5B, MUC6, MUC19, WISP1, WISP2, WISP3, VWF, NOV and Norrie disease (NDP or NORRIN) genes encode proteins with cysteine knot domain. Cysteine-knot superfamily proteins regulate ligand-receptor interactions for a variety of signaling pathways implicated in embryogenesis, homeostasis, and carcinogenesis. Although Ndp is unrelated to Wnt family members, Ndp is claimed to function as a ligand for Fzd4. Here, we identified and characterized rat Ndp, cow Ndp, chicken ndp and zebrafish ndp genes by using bioinformatics. Rat Ndp gene, consisting of three exons, was located within AC105563.4 genome sequence. Cow Ndp and chicken ndp complete CDS were derived from CB467544.1 EST and BX932859.2 cDNA, respectively. Zebrafish ndp gene was located within BX572627.5 genome sequence. Rat Ndp (131 aa) was a secreted protein with C-terminal cysteine knot-like (CTCK) domain. Rat Ndp showed 100, 96.9, 95.4, 87.8 and 66.4 total-amino-acid identity with mouse Ndp, cow Ndp, human NDP, chicken ndp and zebrafish ndp, respectively. Exon-intron structure of mammalian Ndp orthologs was well conserved. FOXA2, CUTL1 (CCAAT displacement protein), LMO2, CEBPA (C/EBPalpha)-binding sites and triple POU2F1 (OCT1)-binding sites were conserved among promoters of mammalian Ndp orthologs.
Int J Mol Med 2005 May
PMID:Comparative genomics on Norrie disease gene. 1580 14

The use of murine cerebrovascular cells, that is, endothelial and smooth muscle cells, has not been widely employed as a cell culture model for the investigation of cellular mechanisms involved in cerebral amyloid angiopathy (CAA). Difficulties in isolation and propagation of murine cerebrovascular cells and insufficient yields for molecular and cell culture studies have deterred investigators from using mice as a source for cerebrovascular cells in culture. To date, most of the literature has described isolation of smooth muscle cells or endothelial cells from human, canine, rat, guinea pig, or other large animals. In recent years, several transgenic mice have been established that show CAA pathology; therefore, it is necessary to re-examine the use of mouse cerebrovascular cells as an important model for cell culture studies. We have optimized the isolation procedure of (1) murine microvessels, (2) smooth muscle cells, and (3) endothelial cells to yield a sufficient population of cells for experimentation purposes. Comparisons with rat and human isolation procedures are also noted. Murine smooth muscle cells isolated using the methodology described herein exhibit the classic "hill and valley" morphology and are immunoreactive for smooth muscle cell-specific alpha-actin, whereas endothelial cells demonstrate a more "cobblestone" appearance and stain for von Willebrand factor or factor VIII-related antigen.
Methods Mol Biol 2005
PMID:Murine cerebrovascular cells as a cell culture model for cerebral amyloid angiopathy: isolation of smooth muscle and endothelial cells from mouse brain. 1598 Jun 4

The purpose of this research was to evaluate the immunohistochemical expression of the vascular endothelial growth factor (VEGF-C1) and measuring the angiogenic activity by the staining for von Willebrand factor (vWF) and CD31 in oral pyogenic granulomas and hemangiomas. The results showed that there was no statistically significant difference in the angiogenesis index between the lesions evaluated. The average microvessel density determined for MVC (microvessel count) using CD31 was 60.64 for hemangiomas and 59.64 for pyogenic granulomas, while angiogenic index determined using vWF was 64.24 and 62.20 in these lesions. The results showed that the cells highlighted by staining for vWF were more uniform than in those stained for CD31. There was no statistically significant difference between the lesions for the number of cells highlighted by staining for VEGF-C1. However, the mean number of cells highlighted in pyogenic granuloma specimens was higher (153.23) when compared to oral hemangioma specimens (115.17). The VEGF-positive cells were endothelial cells and fibroblasts in hemangiomas and macrophages and fibroblasts in pyogenic granulomas. These results effort the role of the angiogenic factors in the etiopathogenesis of the hemangiomas and pyogenic granulomas, however, it showed that microvessel quantification is not useful in the differential diagnosis of these lesions.
Exp Mol Pathol 2005 Aug
PMID:Assessment of angiogenic markers in oral hemangiomas and pyogenic granulomas. 1600 15

Certain plant-derived compounds show selective estrogen receptor modulator (SERM) activity and may therefore be an alternative to the conventional hormone replacement therapy, which prevents osteoporosis but is also associated with an increased risk of breast and endometrial cancers. In the current study, we tested the effects of the hop-derived compounds 8-prenylnaringenin, 6-prenylnaringenin, xanthohumol and isoxanthohumol (1) to modulate markers of differentiation and gene expression in osteoblasts and (2) to regulate proliferation in MCF-7 breast cancer cells. Additionally, we analyzed the ER-binding affinities of these hop compounds as well as the ER-mediation of their effects. Bone-forming activity and ER-subtype specificity were investigated by measuring alkaline phosphatase (AP) activity in hFOB/ERalpha cells and regulation of gene transcription for AP, interleukin-6, pS2 and von Willebrand factor (VWF) in U-2 OS/ERalpha and U-2 OS/ERbeta cells. Our results demonstrate that AP, pS2 and VWF mRNA levels are significantly increased by the compounds in an estrogen-like manner via both ERalpha and ERbeta, while IL-6 is down-regulated in U-2 OS/ERalpha cells. Consistently, AP enzymatic activity is up-regulated by all compounds in hFOB/ERalpha9 cells. Depending on their concentration, all compounds show proliferative effects in MCF-7 cells. Except for 8-PN the hop constituents display an ERbeta-preference. Reversal of estrogen-specific AP-induction in Ishikawa cells indicates an ER-regulated mechanism. Finally, the flavonoids display cytotoxic effects only at high concentrations (> or =10(-4)M). In summary, we have demonstrated for the first time that specific phytoestrogen compounds found in hop extracts exert estrogen-like activities on bone metabolism. Regarding a potential for use in osteoporosis-prevention therapy, the dosage of a phytoestrogen, which is taken, will play an important role concerning a desired in vivo profile.
J Steroid Biochem Mol Biol 2005 Sep
PMID:Regulation of osteoblastic phenotype and gene expression by hop-derived phytoestrogens. 1601 5

Many antithrombotic agents have only a small therapeutic window, frequently leading to bleeding problems. However, interfering with platelet adhesion through the collagen-VWF-GPIbalpha axis is expected to cause less bleeding problems. Our group developed a monoclonal antibody, 82D6A3, directed against the von Willebrand factor (VWF) A3-domain, which inhibits the VWF-interaction to fibrillar collagen. 82D6A3 has antithrombotic effects in vivo without bleeding time prolongation. To further investigate the promising features of 82D6A3, we have humanized it by variable domain resurfacing and grafting on the constant regions of a human IgG4. First, the sequence of the variable domains was determined and the murine scFv was constructed. The expressed scFv had a comparable activity as the IgG of 82D6A3, and its DNA was thus used in subsequent humanization procedures. For this, a new approach was introduced to identify non-human like framework surface residues, since the general distribution of accessible residues described for human and murine heavy and light chain variable domains showed several discrepancies with the homology modelled Fv of 82D6A3. Identification of non-human like framework residues and evaluation of their surface accessibility within the context of the homology modelled Fv of 82D6A3, revealed 10 residues that need to be humanized without influencing the conformation of the CDR loops. Indeed, the humanized scFv of 82D6A3, obtained by mutating all 10 residues to their human counterpart, was still binding with high affinity to VWF and retained the inhibitory properties of the murine scFv. Next, in order to increase its half life and to decrease its immunogenicity, the humanized variable domains were grafted on the constant regions of a human IgG4, resulting in h82D6A3 with an in vitro activity comparable to that of the murine IgG.
Mol Immunol 2006 Mar
PMID:Humanization by variable domain resurfacing and grafting on a human IgG4, using a new approach for determination of non-human like surface accessible framework residues based on homology modelling of variable domains. 1611 19

Von Willebrand disease (VWD) is a common inherited bleeding disorder caused by quantitative (types 1 and 3) and qualitative (type 2) defects in von Willebrand factor (VWF). The VWF gene is a large gene containing 52 exons; except for type 2 VWD, the majority of mutations causing VWD are not localized to specific exons. We have used denaturing high performance liquid chromatography (DHPLC) to scan the coding region of the VWF gene for sequence variations. Primers were designed to amplify all 52 exons while avoiding amplification of the VWF pseudogene. Exon-specific primers were designed with sequencing primers, allowing direct sequencing of each VWF exon. Sequence variations in 33 previously characterized von Willebrand disease (VWD) samples were all detected using DHPLC demonstrating the high sensitivity of this technique. In addition, we analyzed 42 patients or family members with VWD. Thirty-two novel sequence variations were identified (2 deletions, 2 nonsense, 15 missense, 6 silent, and 7 intronic), some with clear functional consequences. A previously described deletion in exon 18, 2435delC, was also found in two unrelated type 3 patients. This DHPLC and DNA sequencing technique will enable the full length assessment of the VWF gene necessary to detect mutations causing types 1 and 3 VWD.
Mol Genet Metab 2006 Mar
PMID:Genetic mutations in von Willebrand disease identified by DHPLC and DNA sequence analysis. 1632 53

Modification of tyrosine residues in extracellular proteins by a sulfate moity plays an important role in many ligand/receptors interactions. In the present work, we describe a unique human monoclonal antibody, termed Y1-scFv, that is specific for a sulfated epitope in the platelat receptor GPIb. The Y1-scFv single chain antibody (scFv) competes with von Willebrand factor (vWF) for binding to human platelets and thus effectively inhibits platelet aggregation. Limited proteolysis of GPIb molecule, using the endoproteases, mocarhagin and cathepsin G, revealed that a seven amino-acid epitope, Tyr-276 to Glu-282, contains the recognition site for Y1-scFv. This GPIb region contains three sulfated tyrosine residues. Binding studies of Y1-scFv to cells and to synthetic peptides in vitro indicated that of the seven residues comprising the epitope only sulfo-Tyr-276 and adjacent Asp-277 are critical for the interaction. To identify the reciprocal sequences in the antibody that recognize the sulfated epitope, we introduced mutations within the complementary-determining region of the heavy chain (CDR3H) of Y1-scFv (MRAPVI). Arginine residue in the second position was critical for the binding. Moreover, a mutant, containing two sequential arginine residues, in the second and third positions of the CDR3H (MRRPVI), showed a nine-fold increased binding to GPIb. This antibody mutant also demonstrated a significant increase in inhibition of vWF-dependent platelet aggregation and adhesion under flow. In conclusion, this unique antibody and mutants, that recognize a sulfated epitope in GP1b receptor, efficiently inhibited platelet adhesion and aggregation, making it a candidate for a new anti-thrombotic agent.
Mol Immunol 2006 Feb
PMID:Molecular characterization of a human monoclonal antibody that interacts with a sulfated tyrosine-containing epitope of the GPIb receptor and inhibits platelet functions. 1633 87


<< Previous 1 2 3 4 5 6 7 8 9 10