Insulin-like growth factor II peptide fusion enables uptake and lysosomal delivery of {alpha}-N-acetylglucosaminidase to mucopolysaccharidosis type IIIB fibroblasts
Enzyme replacement therapy for mucopolysaccharidosis type IIIB (MPS IIIB; Sanfilippo B syndrome) has been hindered by inadequate mannose 6-phosphorylation and cellular uptake of recombinantly produced human α-N-acetyl-glucosamindase (rhNAGLU). We expressed and characterized a modified, recombinant human NAGLU fused to the receptor binding motif of insulin-like growth factor-II (rhNAGLU-IGF-II) to enhance its ability to enter cells using the cation-independent mannose 6-phosphate receptor, which is also the receptor for IGF-II (at a different binding site). RhNAGLU-IGF-II was stably expressed in Chinese hamster ovary...
Source: BJ Disease - November 25, 2013 Category: Biochemistry Authors: S Kan, L A. Troitskaya, C S. Sinow, K Haitz, A K. Todd, A Di Stefano, S Q. Le, P I. Dickson, B L. Tippin Tags: BJ Disease Source Type: research
Site Restricted Plasminogen Activation Mediated by Group A Streptococcal Streptokinase Variants
Streptokinase (SK) is a secreted plasminogen activator and virulence factor of group A streptococcus (GAS). Among GAS isolates, SK gene sequences are polymorphic and are grouped into two sequence clusters (cluster type-1 and cluster type-2) with cluster type-2 being further classified into sub-clusters (type-2a and type-2b). Here we examine the role of bacterial and host-derived cofactors in SK mediated plasminogen activation. All SK variants, apart from type-2b, can form an activator complex with Glu-plasminogen (Glu-Plg). Specific ligand-binding induced conformational changes in Glu-Plg mediated by fibrinogen, plasminoge...
Source: BJ Disease - November 22, 2013 Category: Biochemistry Authors: S M. Cook, A Skora, M J. Walker, M L. Sanderson-Smith, J D. McArthur Tags: BJ Disease Source Type: research
Structural insights into the small G protein Arl13B and implications for Joubert syndrome
Ciliopathies are human diseases arising from defects in primary or motile cilia. The small G
protein Arl13B localizes to microtubule doublets of the ciliary axoneme and is mutated in
Joubert Syndrome. Its GDP-GTP mechanistic cycle and the impact of patient mutations
remain elusive. Here, we applied high resolution structural and biochemical approaches to
study Arl13B. The crystal structure of Chlamydomonas rheinhardtii Arl13B comprising Gdomain
and part of its unique C-terminus and biochemical experiments reveal the lack of
intrinsic hydrolysis and the absence of a catalytic residue in the active site. The structure
shows ...
Source: BJ Disease - October 30, 2013 Category: Biochemistry Authors: M Miertzschke, C Koerner, M Spoerner, A Wittinghofer Tags: BJ Biomolecules Source Type: research
A novel DYRK1B inhibitor, AZ191, demonstrates that DYRK1B acts independently of GSK3{beta} to phosphorylate cyclin D1 at threonine-286, not threonine-288
The dual-specificity tyrosine phosphorylation-regulated kinase, DYRK1B, is amplified in certain cancers and may be an oncogene; however, our knowledge of DYRK1B has been limited by the lack of selective inhibitors. Here we describe AZ191, a potent small molecule inhibitor that selectively inhibits DYRK1B in vitro and in cells. Cyclin D1 (CCND1), a key regulator of the mammalian G1-S phase transition, is phosphorylated on threonine-286 (T286) by GSK3β to promote its degradation. DYRK1B has also been proposed to promote CCND1 turnover but was reported to phosphorylate T288 rather than T286. Using in vitro kinase assay...
Source: BJ Disease - October 17, 2013 Category: Biochemistry Authors: A L. Ashford, D Oxley, J Kettle, K Hudson, S Guichard, S J. Cook, P A. Lochhead Tags: BJ Signal Source Type: research
Native oligomerization determines the mode of action and biological activities of human cathelicidin LL-37
LL-37 is a multifunctional component of innate immunity, with a membrane-directed antimicrobial activity and receptor-mediated pleiotropic effects on host cells. Sequence variations in its primate orthologues suggest two types of functional features have evolved; human LL-37-like peptides form amphipathic helical structures and self-assemble under physiological conditions, while rhesus RL-37-like ones only adopt this structure in the presence of bacterial membranes. The first type of peptide has a lower and more medium-sensitive antimicrobial activity than the second, but an increased capacity to stimulate host cells. Olig...
Source: BJ Disease - October 14, 2013 Category: Biochemistry Authors: D Xhindoli, S Pacor, F Guida, N Antcheva, A Tossi Tags: BJ Biomolecules Source Type: research
Extended interaction network of Procollagen C-Proteinase Enhancer-1 in the extracellular matrix
Procollagen C-proteinase enhancer 1 (PCPE-1) is an extracellular matrix glycoprotein that can stimulate procollagen processing by procollagen C-proteinases such as bone morphogenetic protein-1 (BMP-1). PCPE-1 interacts with several proteins in addition to procollagens and BMP-1 suggesting it could be involved in other biological processes than collagen maturation. We thus searched for additional partners of PCPE-1 in the extracellular matrix, which could provide new insights into its biological roles. We identified seventeen new partners of PCPE-1 by surface plasmon resonance imaging (SPRi). PCPE-1 forms a transient comple...
Source: BJ Disease - October 14, 2013 Category: Biochemistry Authors: R Salza, F Peysselon, E Chautard, C Faye, L Moschcovich, T Weiss, L Perrin-Cocon, V Lotteau, E Kessler, S Ricard-Blum Tags: BJ Biomolecules Source Type: research
The smoking-associated oxidant hypothiocyanous acid induces endothelial nitric oxide synthase dysfunction
In this study it is shown that exposure of isolated eNOS to HOSCN or MPO/H2O2/SCN–, decreased active dimeric eNOS levels, and increased inactive monomer and zinc release, compared to controls, HOCl or MPO/H2O2/Cl– treated samples. eNOS activity was increasingly compromised by MPO/H2O2/Cl– with increasing SCN– concentrations. Exposure of human coronary artery endothelial cell (HCAEC) lysates to pre-formed HOSCN, or MPO/H2O2/Cl- with increasing SCN–, increased eNOS monomerization and zinc release, and decreased activity. Intact HCAECs exposed to HOCl and HOSCN had decreased eNOS activity an...
Source: BJ Disease - October 10, 2013 Category: Biochemistry Authors: J Talib, J Kwan, A Suryo Rahmanto, P K Witting, M J Davies Tags: BJ Energy Source Type: research
TNF induces the expression of the sialyltransferase ST3Gal IV in human bronchial mucosa via MSK1/2 protein kinases and increases FliD/sialyl-Lewisx mediated adhesion of Pseudomonas aeruginosa.
We have previously shown that the pro-inflammatory cytokine TNF (tumour necrosis factor) could drive sLex (sialyl-Lewisx) biosynthesis through the up-regulation of the BX transcript isoform of ST3GAL4 sialyltransferase gene in lung epithelial cells and human bronchial mucosa. Here, we show that the TNF-induced up-regulation of ST3GAL4 BX transcript is mediated by the mitogen and stress activated protein kinases MSK1/2 through Erk (extracellular signal-regulated kinase) and p38 MAPK (mitogen-activated protein kinase) pathways, and increases sLex expression on high molecular weight glycoproteins in the inflamed airway epithe...
Source: BJ Disease - October 8, 2013 Category: Biochemistry Authors: F Colomb, O Vidal, M Bobowski, M Krzewinski-Recchi, A Harduin-Lepers, E Mensier, S Jaillard, J Lafitte, P Delannoy, S Groux-Degroote Tags: BJ Signal Source Type: research
A symptomatic Fabry disease mouse model generated by inducing globotriaosylceramide synthesis
In this study, we generated a symptomatic mouse model (G3Stg/GLAko) by crossbreeding GLAko mice with transgenic mice expressing human Gb3 synthase. G3Stg/GLAko mice had high Gb3 levels in major organs, and their serum Gb3 level at 5-25 weeks of age was 6-10 times higher than that in GLAko mice of the same age. G3Stg/GLAko mice showed progressive renal impairment, with albuminuria at 3 weeks of age, decreased urine osmolality at 5 weeks, polyuria at 10 weeks, and increased blood urea nitrogen at 15 weeks. The urine volume and urinary albumin concentration were significantly reduced in the G3Stg/GLAko mice when human recombi...
Source: BJ Disease - October 7, 2013 Category: Biochemistry Authors: A Taguchi, H Maruyama, M Nameta, T Yamamoto, J Matsuda, A B Kulkarni, H Yoshioka, S Ishii Tags: BJ Disease Source Type: research
Cardioprotective 3{'},4{'}-dihydroxyflavonol attenuation of JNK and p38MAPK signalling involves CaMKII inhibition
3’,4’-dihydroxyflavonol (DiOHF) is cardioprotective against ischemia/reperfusion (I/R) injury. The biological activities of flavonols are associated with kinase modulation to alter cell signalling. We thus investigated the effects of DiOHF on the activation of mitogen-activated protein kinases that regulate the cardiac stress response. In an ovine model of I/R, JNK, p38MAPK, ERK and AKT were activated, and NP202, a pro-drug of DiOHF, reduced infarct size and inhibited JNK and p38MAPK activation while ERK and AKT phosphorylation were unaltered. Similarly, in cultured myoblasts, DiOHF pretreatment preserved via...
Source: BJ Disease - September 16, 2013 Category: Biochemistry Authors: N R. Lim, C J. Thomas, L S. Silva, Y Y. Yeap, S Yap, J R. Bell, L M. D. Delbridge, M A. Bogoyevitch, O L. Woodman, S J. Williams, C N. May, D C. H. Ng Tags: BJ Signal Source Type: research
Differential contribution of isoaspartate post-translational modifications to the fibrillization and toxic properties of amyloid-{beta} and the asparagine 23 Iowa mutation
Mutations within amyloid-β (Aβ), especially those clustered at residues 21-23, are linked to early onset Alzheimer’s disease (AD) and primarily associated with cerebral amyloid angiopathy. The Iowa variant, a substitution of aspartic acid for asparagine at position 23 (D23N), associates with widespread vascular amyloid and abundant diffuse pre-amyloid lesions significantly exceeding the incidence of mature plaques. Brain Iowa deposits consist primarily of a mixture of mutated and non-mutated Aβ species exhibiting partial aspartate isomerization at positions 1, 7, and 23. The present work analyze...
Source: BJ Disease - September 13, 2013 Category: Biochemistry Authors: S Fossati, K Todd, K Sotolongo, J Ghiso, A Rostagno Tags: BJ Disease Source Type: research
HEXIM1 downregulates Hypoxia Inducible Factor-1 alpha protein stability
We have previously reported on the inhibition of Hypoxia Inducible Factor alpha (HIF-1α) regulated pathways by Hexamethylene-bis-acetamide-inducible (HMBA) protein 1 (HEXIM1). Disruption of HEXIM1 activity in a knock-in mouse model expressing a mutant HEXIM1 protein resulted in increased susceptibility to the development of mammary tumors, partly by upregulation of vascular endothelial growth factor (VEGF) expression, HIF-1α expression, and aberrant vascularization. We now report on the mechanistic basis for HEXIM1 regulation of HIF-1α. We observed direct interaction between HIF-1α and HEXIM1 an...
Source: BJ Disease - September 10, 2013 Category: Biochemistry Authors: I Yeh, N Ogba, H Bensigner, S M. Welford, M M. Montano Tags: BJ Signal Source Type: research
The air-water interface determines the outcome of seeding during amyloidogenesis
Amyloid formation is a hallmark of protein misfolding diseases (e.g. type II diabetes mellitus). The energetically unfavourable nucleation step of amyloidogenesis can be accelerated by seeding, during which pre-formed aggregates act as templates for monomer recruitment. Hydrophobic-hydrophilic interfaces (e.g. air-water interface, AWI) can also catalyse amyloidogenesis due to the surfactant properties of amyloidogenic polypeptides.
Using Thioflavin T fluorescence and electron microscopy, we demonstrate that the outcome of seeding on human islet amyloid polypeptide amyloidogenesis is dependent upon whether the AWI is pres...
Source: BJ Disease - September 10, 2013 Category: Biochemistry Authors: B J Trigg, C Lee, D J Vaux, L Jean Tags: BJ Biomolecules Source Type: research
Calmodulin Modulates the Termination Threshold for Cardiac Ryanodine Receptor Mediated Ca2{+} Release
Cardiac ryanodine receptor (RyR2)-mediated Ca2+ release in cardiomyocytes terminates when the sarcoplasmic reticulum Ca2+ content depletes to a threshold level, known as the termination threshold. Despite its importance, little is known about the mechanism that regulates the termination threshold. Calmodulin (CaM) by inhibiting RyR2 has been implicated in Ca2+ release termination, but whether CaM modulates the termination threshold is unknown. To this end, we monitored the endoplasmic reticulum Ca2+ dynamics in RyR2-expressig HEK293 cells transfected with CaM wild type (WT) or mutants. We found ...
Source: BJ Disease - August 30, 2013 Category: Biochemistry Authors: X Tian, Y Tang, Y Liu, R Wang, S Chen Tags: BJ Biomolecules Source Type: research
Autophagy impairment aggravates the inhibitory effects of high glucose on osteoblast viability and function
In this study, we explored the putative protective role of autophagy in osteoblastic cells exposed to high glucose (HG) medium. HG was found to increase protein oxidation and triggered autophagy by a mechanism dependent on reactive oxygen species overproduction in osteoblastic MC3T3-E1 cells. MC3T3-E1 cell survival was impaired by HG and worsened by chemical or genetic inhibition of autophagy. These findings were mimicked by H2O2-induced oxidative stress in these cells. Autophagy impairment led to both defective mitochondrial morphology and decreased bioenergetic machinery, and inhibited further osteoblast differentiation ...
Source: BJ Disease - August 27, 2013 Category: Biochemistry Authors: A Bartolomé, A López-Herradón, S Portal-Núñez, A García-Aguilar, P Esbrit, M Benito, C Guillén Tags: BJ Disease Source Type: research
