A requirement for WT Ras Isoforms in mutant KRas-driven signaling and transformation
This study demonstrates that the WT copies of H, N and KRas play unique roles in the context of mutant KRas-driven tumors. (Source: BJ Disease)
Source: BJ Disease - March 18, 2013 Category: Biochemistry Authors: C Bentley, S S Jurinka, N M Kljavin, S Vartanian, S R Ramani, L C Gonzalez, K Yu, Z Modrusan, P Du, R Bourgon, R M Neve, D Stokoe Tags: BJ Signal Source Type: research
FSL-61 is a 6-nitroquinolone fluorogenic probe for one-electron reductases in hypoxic cells
This study thus demonstrates the utility of FSL-61 for rapid and non-destructive interrogation of the activity of one-electron reductases in hypoxic cells at the single cell level. (Source: BJ Disease)
Source: BJ Disease - March 12, 2013 Category: Biochemistry Authors: J Su, C P Guise, W R Wilson Tags: BJ ChemBio Source Type: research
Structure-function analysis of full-length midkine reveals novel residues important for heparin-binding and zebrafish embryogenesis
Midkine is a heparin-binding di-domain growth factor, implicated in many biological processes as diverse as angiogenesis, neurogenesis and tumorigenesis. Elevated midkine levels reflect poor prognosis for many carcinomas, yet the molecular and cellular mechanisms orchestrating its activity remain unclear. Presently, the individual structures of isolated half domains of human midkine are known and its functionally active C-half domain remains a popular therapeutic target. Here, we determined the structure of full length zebrafish midkine and show that it interacts with fondaparinux (a synthetic, highly sulfated pentasacchar...
Source: BJ Disease - February 18, 2013 Category: Biochemistry Authors: J Lim, S Yao, M Graf, C Winkler, D Yang Tags: BJ Structure Source Type: research
Production of a human neutralizing monoclonal antibody and its crystal structure in complex with the ectodomain 3 of the interleukin-13 receptor {alpha}1
We describe the crystal structures of the Fab fragment of antibody 10G5H6 alone and in complex with the ectodomain 3 (D3) of the IL-13Rα1. Although the structure showed significant domain swapping within a D3 dimer we showed that Arg230, Phe233, Tyr250, Gln252 and Leu293 in each D3 monomer and Ser32, Asn102, and Trp103 in 10G5H6 Fab are the key interacting residues at the interface of the D3:10G5H6 Fab complex. One of the most striking contacts is the insertion of the ligand-contacting residue Leu293 of D3 into a deep pocket on the surface of 10G5H6 Fab and this appears to be a central determinant of the high bindin...
Source: BJ Disease - February 6, 2013 Category: Biochemistry Authors: N T Redpath, Y Xu, N J Wilson, A E Andrews, L J Fabri, M Baca, H Braley, P Lu, C Ireland, R E Ernst, A Woods, G Forrest, Z An, D M Zaller, W R Strohl, C S Luo, P E Czabotar, T PJ Garrett, D J Hilton, A D Nash, J Zhang, N A Nicola Tags: BJ Structure Source Type: research
The CUL3-KLHL3 E3 ligase complex mutated in Gordon's hypertension syndrome interacts with and ubiquitylates WNK isoforms; disease-causing mutations in KLHL3 and WNK4 disrupt interaction.
The WNK [with no lysine (K) kinase]-SPAK/OSR1 signalling pathway plays an important role in controlling mammalian blood pressure by modulating the activity of ion co-transporters in the kidney. Recent studies have identified hypertension Gordon’s syndrome patients with mutations in either Cullin-3 (CUL3) or the BTB-protein Kelch-like 3 (KLHL3). CUL3 assembles with BTB proteins to form Cullin-RING E3 ubiquitin ligase complexes. To explore how a CUL3:KLHL3 complex might operate, we immunoprecipitated KLHL3 and found that it associated strongly with WNK isoforms and CUL3, but not with other components of the pathway (S...
Source: BJ Disease - February 6, 2013 Category: Biochemistry Authors: A Ohta, F Schumacher, Y Mehellou, C Johnson, A Knebel, T J Macartney, N T Wood, D R Alessi, T Kurz Tags: BJ Signal Source Type: research
AdE-1, a new inotropic Na{+} channel toxin from Aiptasia diaphana is similar to, yet distinct from, known anemone Na{+} channel toxins
Heart failure is of the most prevalent causes of death in the western world. Sea anemone contains a myriad of short peptide neurotoxins affecting many pharmacological targets, several of which possess cardiotonic activity. Here we describe the isolation and characterization of AdE-1, a novel cardiotonic peptide from the sea anemone Aiptasia diaphana, which differs from other cnidarian toxins. While AdE-1 has the same cysteine residue arrangement as sea anemone type 1 and 2 Na+ channel toxins, its sequence contains many substitutions in conserved and essential sites and its overall homology to toxins identified to da...
Source: BJ Disease - January 28, 2013 Category: Biochemistry Authors: N Nesher, E Shapira, D Sher, Y Moran, L Tsveyer, A Turchetti-Maia, M Horowitz, B Hochner, E Zlotkin Tags: BJ ChemBio Source Type: research
Polyamine production is downstream and upstream of oncogenic PI3K signalling and contributes to tumour cell growth
PI3K signaling pathways regulate a large array of cell biological functions in normal and cancer cells. Here we investigated the involvement of PI3K in modulating small molecule metabolism. A LC-MS screen in colorectal cancer cell lines isogenic for oncogenic PIK3CA mutations revealed an association between PI3K activation and the levels of polyamine pathway metabolites, including 5-methylthioadenosine, putrescine and spermidine. Pharmacological inhibition confirmed that the PI3K pathway controls polyamine production. Despite inducing a decrease in PKB/Akt phosphorylation, spermidine promoted cell survival and opposed the ...
Source: BJ Disease - January 18, 2013 Category: Biochemistry Authors: V Rajeeve, W Pearce, M Cascante, B Vanhaesebroeck, P R Cutillas Tags: BJ Disease Source Type: research
Structure of Plasmodium falciparum Thrombospondin-Related Anonymous Protein (TRAP) A domain highlights distinct features in apicomplexan von Willebrand Factor A homologues
Thrombospondin-related anonymous protein (TRAP), localized in the micronemes and on the surface of sporozoites of infamous malaria parasite Plasmodium, is a key molecule upon infection of mammalian host hepatocytes and invasion of mosquito salivary glands. TRAP contains two adhesive domains responsible for host cell recognition and invasion, and is known to be essential for infectivity. Here we report high resolution crystal structures of the A domain of Plasmodium falciparum TRAP with and without bound Mg2+. The structure reveals a von Willebrand factor A (vWA)-like fold and a functional metal ion-dependent adhesio...
Source: BJ Disease - January 15, 2013 Category: Biochemistry Authors: T Pihlajamaa, T Kajander, J Knuuti, K Horkka, A Sharma, P Permi Tags: BJ Structure Source Type: research
Allosteric inhibition of VIM metallo-{beta}-lactamases by a camelid nanobody
Metallo-β-lactamase (MβL) enzymes are usually produced by multiresistant Gram-negative bacterial strains and have spread worldwide. An approach based on phage display was employed to select single-domain antibody fragments (VHHs also called Nanobodies) that would inhibit the clinically relevant VIM-4 MβL. Out of more than 50 selected nanobodies, only the NbVIM_38 nanobody inhibited VIM-4. The paratope, inhibition mechanism and epitope of NbVIM_38 nanobody were then characterised.
An alanine scan of the NbVIM_38 paratope showed that its binding was driven by hydrophobic amino acids. The inhibitory conc...
Source: BJ Disease - January 7, 2013 Category: Biochemistry Authors: J Sebastien Sohier, C Laurent, A Chevigné, E Pardon, V Srinivasan, U Wernery, J Steyaert, M Galleni Tags: BJ Structure Source Type: research
para-sulfonato-calix[n]arenes inhibit staphylococcal bicomponent leukotoxins by supramolecular interactions
This study characterized leukotoxin inhibition by selected para-sulfonato-calix[n]arenes (SCn): SC4, SC6 and SC8. These chemicals have no toxic effects on human erythrocytes or neutrophils, and some are able to inhibit both activity and cell lysis by leukotoxins in a dose-dependent manner. Depending on leukotoxins and SCn, flow cytometry revealed IC50 values between 6–22 µM for Ca2+-activation and between 2–50 µM for cell lysis. SCn were observed to affect membrane binding of class S proteins responsible for cell specificity. Electrospray Mass Spectrometry and Surface Plasmon Resonance es...
Source: BJ Disease - January 3, 2013 Category: Biochemistry Authors: B Laventie, C Potrich, C Atmanène, M Saleh, O Joubert, G Viero, C Bachmeyer, V Antonini, I Mancini, S Cianferani-Sanglier, D Keller, D A. Colin, T Bourcier, G Anderluh, A van Dorsselaer, M Dalla Serra, G Prévost Tags: BJ ChemBio Source Type: research
