TY  - JOUR
AB  - Advanced glycation end products (AGEs) are non-enzymatic post-translational modifications of amino acids and are associated with diabetic complications. One proposed pathomechanism is the impaired processing of AGE-modified proteins or peptides including prohormones. Two approaches were applied to investigate whether substrate modification with AGEs affects the processing of substrates like prohormones to the active hormones. First, we employed solid-phase peptide synthesis to generate unmodified as well as AGE-modified protease substrates. Activity of proteases towards these substrates was quantified. Second, we tested the effect of AGE-modified proinsulin on the processing to insulin. Proteases showed the expected activity towards the unmodified peptide substrates containing arginine or lysine at the C-terminal cleavage site. Indeed, modification with Nε-carboxymethyllysine (CML) or methylglyoxal-hydroimidazolone 1 (MG-H1) affected all proteases tested. Cysteine cathepsins displayed a reduction in activity by ∼50% towards CML and MG-H1 modified substrates. The specific proteases trypsin, proprotein convertases subtilisin-kexins (PCSKs) type proteases, and carboxypeptidase E (CPE) were completely inactive towards modified substrates. Proinsulin incubation with methylglyoxal at physiological concentrations for 24 h resulted in the formation of MG-modified proinsulin. The formation of insulin was reduced by up to 80% in a concentration-dependent manner. Here, we demonstrate the inhibitory effect of substrate-AGE modifications on proteases. The finding that PCSKs and CPE, which are essential for prohormone processing, are inactive towards modified substrates could point to a yet unrecognized pathomechanism resulting from AGE modification relevant for the etiopathogenesis of diabetes and the development of obesity.
AU  - Brings, S.*
AU  - Mier, W.*
AU  - Beijer, B.*
AU  - Kliemank, E.*
AU  - Herzig, S.
AU  - Szendroedi, J.
AU  - Nawroth, P.P.*
AU  - Fleming, T.
C1  - 69064
C2  - 55195
CY  - 1st Flr, 10 Queen Street Place, London, England
SP  - 33-44
TI  - Non-cross-linking advanced glycation end products affect prohormone processing.
JO  - Biochem. J.
VL  - 481
IS  - 1
PB  - Portland Press Ltd
PY  - 2024
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Adipose tissue is a central regulator of metabolism and an important pharmacological target to treat the metabolic consequences of obesity, such as insulin resistance and dyslipidemia. Among the various cellular compartments, the adipocyte cell surface is especially appealing as a drug target as it contains various proteins that when activated or inhibited promote adipocyte health, change its endocrine function and eventually maintain or restore whole-body insulin sensitivity. In addition, cell surface proteins are readily accessible by various drug classes. However, targeting individual cell surface proteins in adipocytes has been difficult due to important functions of these proteins outside adipose tissue, raising various safety concerns. Thus, one of the biggest challenges is the lack of adipose selective surface proteins and/or targeting reagents. Here, we discuss several receptor families with an important function in adipogenesis and mature adipocytes to highlight the complexity at the cell surface and illustrate the problems with identifying adipose selective proteins. We then discuss that, while no unique adipocyte surface protein might exist, how splicing, posttranslational modifications as well as protein/protein interactions can create enormous diversity at the cell surface that vastly expands the space of potentially unique epitopes and how these selective epitopes can be identified and targeted.
AU  - Onogi, Y.
AU  - Khalil, A.
AU  - Ussar, S.
C1  - 59644
C2  - 48949
SP  - 2509-2541
TI  - Identification and characterization of adipose surface epitopes.
JO  - Biochem. J.
VL  - 477
IS  - 13
PY  - 2020
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Loss of function mutations in the PTEN-induced kinase 1 (PINK1) kinase are causal for autosomal recessive Parkinson's disease (PD) whilst gain of function mutations in the LRRK2 kinase cause autosomal dominant PD. PINK1 indirectly regulates the phosphorylation of a subset of Rab GTPases at a conserved Serine111 (Ser111) residue within the SF3 motif. Using genetic code expansion technologies, we have produced stoichiometric Ser111-phosphorylated Rab8A revealing impaired interactions with its cognate guanine nucleotide exchange factor and GTPase activating protein. In a screen for Rab8A kinases we identify TAK1 and MST3 kinases that can efficiently phosphorylate the Switch II residue Threonine72 (Thr72) in a similar manner as LRRK2 in vitro. Strikingly, we demonstrate that Ser111 phosphorylation negatively regulates the ability of LRRK2 but not MST3 or TAK1 to phosphorylate Thr72 of recombinant nucleotide-bound Rab8A in vitro and demonstrate an interplay of PINK1- and LRRK2-mediated phosphorylation of Rab8A in transfected HEK293 cells. Finally, we present the crystal structure of Ser111- phosphorylated Rab8A and nuclear magnetic resonance structure of Ser111-phosphorylated Rab1B. The structures reveal that the phosphorylated SF3 motif does not induce any major changes, but may interfere with effector-Switch II interactions through intramolecular H-bond formation and/or charge effects with Arg79. Overall, we demonstrate antagonistic regulation between PINK1-dependent Ser111 phosphorylation and LRRK2-mediated Thr72 phosphorylation of Rab8A indicating a potential cross-talk between PINK1-regulated mitochondria' homeostasis and LRRK2 signalling that requires further investigation in vivo.
AU  - Vieweg, S.*
AU  - Mulholland, K.*
AU  - Bräuning, B.*
AU  - Kachariya, N.*
AU  - Lai, Y.C.*
AU  - Toth, R.*
AU  - Singh, P.K.*
AU  - Volpi, I.*
AU  - Sattler, M.
AU  - Groll, M.*
AU  - Itzen, A.*
AU  - Muqit, M.M.K.*
C1  - 59156
C2  - 48719
CY  - 5th Flr, 90 High Holborn, London Wc1v 6lj, England
SP  - 1651-1668
TI  - PINK1-dependent phosphorylation of Serine111 within the SF3 motif of Rab GTPases impairs effector interactions and LRRK2-mediated phosphorylation at Threonine72.
JO  - Biochem. J.
VL  - 477
IS  - 9
PB  - Portland Press Ltd
PY  - 2020
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Activation of AMP-activated protein kinase (AMPK) in endothelial cells regulates energy homeostasis, stress protection and angiogenesis, but the underlying mechanisms are incompletely understood. Using a label-free phosphoproteomic analysis, we identified glutamine:fructose-6-phosphate amidotransferase 1 (GFAT1) as an AMPK substrate. GFAT1 is the rate-limiting enzyme in the hexosamine biosynthesis pathway (HBP) and as such controls the modification of proteins by O-linked β-N-acetylglucosamine (O-GlcNAc). In the present study, we tested the hypothesis that AMPK controls O-GlcNAc levels and function of endothelial cells via GFAT1 phosphorylation using biochemical, pharmacological, genetic and in vitro angiogenesis approaches. Activation of AMPK in primary human endothelial cells by 5-aminoimidazole-4-carboxamide riboside (AICAR) or by vascular endothelial growth factor (VEGF) led to GFAT1 phosphorylation at serine 243. This effect was not seen when AMPK was down-regulated by siRNA. Upon AMPK activation, diminished GFAT activity and reduced O-GlcNAc levels were observed in endothelial cells containing wild-type (WT)-GFAT1 but not in cells expressing non-phosphorylatable S243A-GFAT1. Pharmacological inhibition or siRNA-mediated down-regulation of GFAT1 potentiated VEGF-induced sprouting, indicating that GFAT1 acts as a negative regulator of angiogenesis. In cells expressing S243A-GFAT1, VEGF-induced sprouting was reduced, suggesting that VEGF relieves the inhibitory action of GFAT1/HBP on angiogenesis via AMPK-mediated GFAT1 phosphorylation. Activation of GFAT1/HBP by high glucose led to impairment of vascular sprouting, whereas GFAT1 inhibition improved sprouting even if glucose level was high. Our findings provide novel mechanistic insights into the role of HBP in angiogenesis. They suggest that targeting AMPK in endothelium might help to ameliorate hyperglycaemia-induced vascular dysfunction associated with metabolic disorders.
AU  - Zibrova, D.*
AU  - Vandermoere, F.*
AU  - Göransson, O.*
AU  - Peggie, M.*
AU  - Mariño, K.V.*
AU  - Knierim, A.*
AU  - Spengler, K.*
AU  - Weigert, C.
AU  - Viollet, B.*
AU  - Morrice, N.A.*
AU  - Sakamoto, K.*
AU  - Heller, R.*
C1  - 52819
C2  - 44182
SP  - 983-1001
TI  - GFAT1 phosphorylation by AMPK promotes VEGF-induced angiogenesis.
JO  - Biochem. J.
VL  - 474
IS  - 6
PY  - 2017
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Inherited and de novo mutations in the CARD14 gene promote the development of psoriasis, an inflammatory disease of the skin. CARD14 is a member of the CARMA protein family that includes the structurally related CARD11 adaptor that mediates NF-κB activation by antigen receptors. We investigated the mechanism by which CARD14 mutation in psoriasis activates NF-κB. In contrast to wild type CARD14, CARD14(E138A)and CARD14(G117S)psoriasis mutants interacted constitutively with BCL10 and MALT1, and triggered BCL10 and MALT1 dependent activation of NF-κB in keratinocytes. These alterations disrupted the inhibitory effect of the CARD14 linker region on NF-κB activation by facilitating BCL10 binding. Therefore, psoriasis mutations activated CARD14 by a mechanism analogous to oncogenic CARD11 mutations in non-Hodgkin B cell lymphomas. CARD14(E138A)also stimulated MALT1 paracaspase activity and activated both ERK1/2 and p38α MAP kinases. Inhibition of MALT1 with mepazine reduced CARD14(E138A)-induced expression of specific psoriasis-associated transcripts in keratinocytes. Our results establish the mechanism whereby gain-of-function CARD14 variants, which induce psoriatic disease in affected individuals, activate pro-inflammatory signaling.
AU  - Howes, A.*
AU  - O'Sullivan, P.A.*
AU  - Breyer, F.*
AU  - Ghose, A.*
AU  - Cao, L.*
AU  - Krappmann, D.
AU  - Bowcock, A.M.*
AU  - Ley, S.C.*
C1  - 48391
C2  - 41023
CY  - London
SP  - 1759-1768
TI  - Psoriasis mutations disrupt CARD14 autoinhibition promoting BCL10-MALT1-dependent NF-κB activation.
JO  - Biochem. J.
VL  - 473
IS  - 12
PB  - Portland Press Ltd
PY  - 2016
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - It has been well established that excessive levels of glucose and palmitate lower glucose-stimulated insulin secretion (GSIS) by pancreatic beta cells. This beta cell 'glucolipotoxicity' is possibly mediated by mitochondrial dysfunction, but involvement of bioenergetic failure in the pathological mechanism is subject of ongoing debate. We show here that increased palmitate levels impair GSIS before altering mitochondrial function. We demonstrate that GSIS defects arise from increased insulin release under basal conditions in addition to decreased insulin secretion under glucose-stimulatory conditions. Real-time respiratory analysis of intact mouse pancreatic islets reveals that mitochondrial ATP synthesis is not involved in the mechanism by which basal insulin is elevated. Equally, mitochondrial lipid oxidation and production of reactive oxygen species do not contribute to increased basal insulin secretion. Palmitate does not affect KCl-induced insulin release at a basal or stimulatory glucose level, but elevated basal insulin release is attenuated by palmitoleate and associates with increased intracellular calcium. These findings deepen our understanding of beta cell glucolipotoxicity and reveal that palmitate-induced GSIS impairment is disconnected from mitochondrial dysfunction, a notion that is important when targeting beta cells for the treatment of diabetes and when assessing islet function in human transplants.
AU  - Barlow, J.*
AU  - Hirschberg Jensen, V.*
AU  - Jastroch, M.
AU  - Affourtit, C.*
C1  - 47460
C2  - 40569
TI  - Palmitate-induced impairment of glucose-stimulated insulin secretion precedes mitochondrial dysfunction in mouse pancreatic islets.
JO  - Biochem. J.
PY  - 2015
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - The Jumonji domain-containing protein 6 (Jmjd6) is a member of the superfamily of non-haem iron(II) and 2-oxoglutarate (2OG)-dependent oxygenases; it plays an important developmental role in higher animals. Jmjd6 was initially assigned a role as the phosphatidylserine receptor responsible for engulfment of apoptotic cells but this now seems unlikely. Jmjd6 has been shown to be a nuclear localized protein with a JmjC domain comprising a distorted double-stranded β-helical structure characteristic of the 2OG-dependent oxygenases. Jmjd6 was subsequently assigned a role in catalysing N-methyl-arginine residue demethylation on the N-terminus of the human histones H3 and H4; however, this function is also subject to conflicting reports. Jmjd6 does catalyse 2OG-dependent C-5 hydroxylation of lysine residues in mRNA splicing-regulatory proteins and histones; there is also accumulating evidence that Jmjd6 plays a role in splicing (potentially in an iron- and oxygen-dependent manner) as well as in other processes regulating gene expression, including transcriptional pause release. Moreover, a link with tumour progression has been suggested. In the present review we look at biochemical, structural and cellular work on Jmjd6, highlighting areas of controversy and consensus.
AU  - Böttger, A.*
AU  - Islam, M.S.*
AU  - Chowdhury, R.*
AU  - Schofield, C.J.*
AU  - Wolf, A.
C1  - 44914
C2  - 37121
CY  - London
SP  - 191-202
TI  - The oxygenase Jmjd6-a case study in conflicting assignments.
JO  - Biochem. J.
VL  - 468
IS  - 2
PB  - Portland Press Ltd
PY  - 2015
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Jmjd6 is an Fe(II) and 2-oxoglutarate (2OG) dependent oxygenase that catalyses hydroxylation of lysine residues in proteins involved in pre-mRNA splicing. Jmjd6 plays an essential role in vertebrate embryonic development and has been shown to modulate alternative splicing in response to hypoxic stress. Here we show that an alternatively spliced version of Jmjd6 lacking the polyS domain localises to the nucleolus, predominantly in the fibrillar centre. PolyS domain deleted Jmjd6 also interacts with nucleolar proteins. Furthermore, co-immunoprecipitation experiments and fluorescent 2-hybrid (F2H) assays demonstrate that Jmjd6 homo-oligomerisation occurs in cells. In correlation with the observed variations in the subnuclear distribution of Jmjd6 the structure of Jmjd6 oligomers in vitro changes in the absence of the polyS domain, possibly reflecting the role of the polyS domain in nuclear/nucleolar shuttling of Jmjd6.
AU  - Wolf, A.
AU  - Mantri, M.*
AU  - Heim, A.*
AU  - Müller, U.*
AU  - Fichter, E.*
AU  - Mackeen, M.M.*
AU  - Schermelleh, L.*
AU  - Dadie, G.*
AU  - Leonhardt, H.*
AU  - Vénien-Bryan, C.*
AU  - Kessler, B.M.*
AU  - Schofield, C.J.*
AU  - Böttger, A.*
C1  - 25792
C2  - 31925
SP  - 357-370
TI  - The poly-serine domain of the lysyl-5 hydroxylase Jmjd6 mediates subnuclear localization.
JO  - Biochem. J.
VL  - 453
IS  - 3
PB  - Portland Press
PY  - 2013
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Bile acids from duodenogastric reflux promote inflammation and increase the risk for gastro-oesophageal cancers. FXR (farnesoid X receptor/NR1H4) is a transcription factor regulated by bile acids such as CDCA (chenodeoxycholic acid). FXR protects the liver and the intestinal tract against bile acid overload; however, a functional role for FXR in the stomach has not been described. We detected FXR expression in the normal human stomach and in GC (gastric cancer). FXR mRNA and protein were also present in the human GC cell lines MKN45 and SNU5, but not in the AGS cell line. Transfection of FXR into AGS cells protected against TNFα (tumour necrosis factor α)-induced cell damage. We identified K13 (keratin 13), an anti-apoptotic protein of desmosomes, as a novel CDCA-regulated FXR-target gene. FXR bound to a conserved regulatory element in the proximal human K13 promoter. Gastric expression of K13 mRNA was increased in an FXR-dependent manner by a chow diet enriched with 1% (w/w) CDCA and by indomethacin (35 mg/kg of body weight intraperitoneal) in C57BL/6 mice. FXR-deficient mice were more susceptible to indomethacin-induced gastric ulceration than their WT (wild-type) littermates. These results suggest that FXR increases the resistance of human and murine gastric epithelial cells to inflammation-mediated damage and may thus participate in the development of GC.
AU  - Lian, F.*
AU  - Xing, X.*
AU  - Yuan, G.*
AU  - Schäfer, C.*
AU  - Rauser, S.
AU  - Walch, A.K.
AU  - Röcken, C.*
AU  - Ebeling, M.*
AU  - Wright, M.B.*
AU  - Schmid, R.M.*
AU  - Ebert, M.P.*
AU  - Burgermeister, E.*
C1  - 6356
C2  - 29155
SP  - 315-323
TI  - Farnesoid X receptor protects human and murine gastric epithelial cells against inflammation-induced damage.
JO  - Biochem. J.
VL  - 438
IS  - 2
PB  - Portland Press
PY  - 2011
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - STAF [Sec (selenocysteine) tRNA gene transcription activating factor] is a transcription activating factor for a number of RNA Pol III- and RNA Pol II-dependent genes including the Trsp [Sec tRNA gene], which in turn controls the expression of all selenoproteins. Here, the role of STAF in regulating expression of Sec tRNA and selenoproteins was examined. We generated transgenic mice expressing the Trsp transgene lacking the STAF-binding site and made these mice dependent on the transgene for survival by removing the wild-type Trsp. The level of Sec tRNA was unaffected or slightly elevated in heart and testis, but reduced similar to 60% in liver and kidney, similar to 70% in lung and spleen and similar to 80% in brain and muscle compared with the corresponding organs in control mice. Moreover, the ratio of the two isoforms of Sec tRNA that differ by methylation at position 34 (Um34) was altered significantly, and the Um34-containing form was substantially reduced in all tissues examined. Selenoprotein expression in these animals was most affected in tissues in which the Sec tRNA levels were most severely reduced. Importantly, mice had a neurological phenotype strikingly similar to that of mice in which the selenoprotein P gene had been removed and their life span was substantially reduced. The results indicate that STAF influences selenoprotein expression by enhancing Trsp synthesis in an organ-specific manner and by controlling Sec tRNA modification in each tissue examined.
AU  - Carlson, B.A.*
AU  - Schweizer, U.*
AU  - Perella, C.*
AU  - Shrimali, R.K.*
AU  - Feigenbaum, L.*
AU  - Shen, L.*
AU  - Speransky, S.*
AU  - Floß, T.
AU  - Jeong, S.J.*
AU  - Watts, J.*
AU  - Hoffmann, V.*
AU  - Combs, G.F.*
AU  - Gladyshev, V.N.*
AU  - Hatfield, D.L.*
C1  - 5729
C2  - 28268
CY  - London
SP  - 61-71
TI  - The selenocysteine tRNA STAF-binding region is essential for adequate selenocysteine tRNA status, selenoprotein expression and early age survival of mice.
JO  - Biochem. J.
VL  - 418
IS  - 1
PB  - Portland Press Ldt.
PY  - 2009
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - GCPs (glycoproteases) are members of the HSP70 (beat-shock protein 70)/actin ATPase superfamily that are highly conserved in taxonomically diverse species from bacteria to man, suggesting an essential physiological role. Although originally identified and annotated as putative endopeptidases, a proteolytic activity could not be confirmed for these proteins. Our survey of genome databases revealed that all eukaryotic organisms contain two GCP genes [called GCP1 and GCP2/Kae1 (kinase-associated endopeptidase 1)], whereas prokaryotes have only one, either of the GCP1-(Bacteria) or the GMIKae1- (Archaea) type. GCP2/Kae1 is essential for telomere elongation and transcription of essential genes, although little is known about the localization, expression and physiological role of GCP1. In the present study on GCP1-type proteins from eukaryotic organisms we demonstrated that GCP1 is a mitochondrial protein in Homo sapiens [called here GCPI/OSGEPL1 (O-sialoglycoprotein endopeptidase)] and Arabidopsis thaliana, which is located/anchored to the mitochondrial inner membrane. Analysis of mRNA and protein levels revealed that the expression of GCP1/OSGEPL1 in A. thaliana and H. sapiens is tissue- and organ-specific and depends on the developmental stage, suggesting a more specialized function for this protein. We showed that homozygous A. thaliana GCP1 T-DNA (transferred DNA) insertion lines were embryonic lethal. Embryos in homozygous seeds were arrested at the globular stage and failed to undergo the transition into the heart stage. On the basis of these data we propose that the mitochondrial GCP1 is essential for embryonic development in plants.
AU  - Haussuehl, K.*
AU  - Huesgen, P.F.*
AU  - Meier, M.
AU  - Dessi, P.*
AU  - Glaser, E.*
AU  - Adamski, J.
AU  - Adamska, I.*
C1  - 103
C2  - 26860
CY  - London
SP  - 333-341
TI  - Eukaryotic GCP1 is a conserved mitochondrial protein required for progression of embryo development beyond the globular stage in Arabidopsis thaliana.
JO  - Biochem. J.
VL  - 423
IS  - 3
PB  - Portland Press Ltd
PY  - 2009
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - To this day, a significant proportion of the human genome remains devoid of functional characterization. In this study, we present evidence that the previously functionally uncharacterized product of the human DHRS10 gene is endowed with 17b-HSD (17b-hydroxysteroid dehydrogenase) activity. 17b-HSD enzymes are primarily involved in the metabolism of steroids at the C-17 position and also of other substrates such as fatty acids, prostaglandins and xenobiotics. In vitro, DHRS10 converts NAD+ into NADH in the presence of oestradiol, testosterone and 5-androstene-3b,17b-diol. Furthermore, the product of oestradiol oxidation, oestrone, was identified in intact cells transfected with a construct plasmid encoding the DHRS10 protein. In situ fluorescence hybridization studies have revealed the cytoplasmic localization of DHRS10. Along with tissue expression data, this suggests a role for DHRS10 in the local inactivation of steroids in the central nervous system and placenta. The crystal structure of the DHRS10 apoenzyme exhibits secondary structure of the SDR (short-chain dehydrogenase/reductase) family: a Rossmann-fold with variable loops surrounding the active site. It also reveals a broad and deep active site cleft into which NAD+ and oestradiol can be docked in a catalytically competent orientation.
AU  - Lukacik, P.*
AU  - Keller, B.
AU  - Bunkoczi, G.*
AU  - Kavanagh, K.*
AU  - Lee, W.H.*
AU  - Adamski, J.
C1  - 5865
C2  - 24475
SP  - 419-427
TI  - Structural and biochemical characterization of human orphan DHRS10 reveals a novel cytosolic enzyme with steroid dehydrogenase activity.
JO  - Biochem. J.
VL  - 402
IS  - 3
PB  - Portland Press
PY  - 2007
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Arginine methylation of proteins affects major processes in the cell, including transcriptional regulation, mRNA metabolism, signal transduction and protein sorting. Arginine methylation of Ad (adenovirus) E1B 55-kDa-associated protein E1B-AP5 was recently described by us [Kzhyshkowska, Schutt, Liss, Kremmer, Stauber, Wolf and Dobner (2001) Biochem. J. 358, 305–314]. In this first example of protein arginine methylation analysis in Ad-infected cells, we investigated methylation of the E1B-AP5 and the viral L4-100 kDa protein. We demonstrate that E1B-AP5 methylation is enhanced during the course of infection in a cell-type-specific manner. We also show that L4-100 kDa is efficiently methylated in Ad-infected cells. L4-100 kDa formed complex with methyltransferase in vivo during productive infection, and can be methylated by HRMT1L2 (human protein arginine methyltransferase 1) in vitro. Comparative analysis of E1B-AP5 and L4-100 kDa protein methylation in Ad-infected HeLa, MCF-7 and H1299 cells revealed that the profile of protein arginine methylation correlates with the efficiency of Ad proteins production. Our results suggest that protein arginine methylation is an important host-cell function required for efficient Ad replication.
AU  - Kzhyshkowska, J.*
AU  - Kremmer, E.
AU  - Hofmann, M.*
AU  - Wolf, H.*
AU  - Dobner, T.*
C1  - 3468
C2  - 22102
SP  - 259-265
TI  - Protein arginine methylation during lytic adenovirus infection.
JO  - Biochem. J.
VL  - 383
IS  - 2
PY  - 2004
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - The large GTPase GBP-1 (guanylate-binding protein-1) is a major IFN-γ (interferon-γ)-induced protein with potent anti-angiogenic activity in endothelial cells. An ISRE (IFN-α-stimulated response element) is necessary and sufficient for the induction of GBP-1 expression by IFN-γ. Recently, we have shown that in vivo GBP-1 expression is strongly endothelial-cell-associated and is, in addition to IFN-γ, also activated by interleukin-1β and tumour necrosis factor-α, both in vitro and in vivo [Lubeseder-Martellato, Guenzi, Jörg, Töpolt, Naschberger, Kremmer, Zietz, Tschachler, Hutzler, Schwemmle et al. (2002) Am. J. Pathol. 161, 1749–1759; Guenzi, Töpolt, Cornali, Lubeseder-Martellato, Jörg, Matzen, Zietz, Kremmer, Nappi, Schwemmle et al. (2001) EMBO J. 20, 5568–5577]. In the present study, we identified a NF-κB (nuclear factor κB)-binding motif that, together with ISRE, is required for the induction of GBP-1 expression by interleukin-1β and tumour necrosis factor-α. Deactivation of the NF-κB motif reduced the additive effects of combinations of these cytokines with IFN-γ by more than 50%. Importantly, NF-κB p50 rather than p65 activated the GBP-1 promoter. The NF-κB motif and ISRE were detected in an almost identical spatial organization, as in the GBP-1 promoter, in the promoter regions of various inflammation-associated genes. Therefore both motifs may constitute a cooperative inflammatory cytokine response module that regulates GBP-1 expression. Our findings may open new perspectives for the use of NF-κB inhibitors to support angiogenesis in inflammatory diseases including ischaemia.
AU  - Naschberger, E.
AU  - Werner, T.
AU  - Vicente, A.B.*
AU  - Guenzi, E.
AU  - Töpolt, K.
AU  - Leubert, R.
AU  - Lubseder-Martellato, C.
AU  - Nelson, P.J.*
AU  - Stürzl, M.
C1  - 5061
C2  - 21862
SP  - 409-420
TI  - Nuclear factor-kB motif and interferon-alpha-stimulated response element co-operate in the activation of guanylate-binding protein-1 expression by inflammatory cytokines in endothelial cells.
JO  - Biochem. J.
VL  - 379
IS  - 2
PY  - 2004
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - The heterogeneous nuclear ribonucleoprotein (hnRNP) family includes predominantly nuclear proteins acting at different stages of mRNA metabolism. A characteristic feature of hnRNPs is to undergo post-translational asymmetric arginine methylation catalysed by different type 1 protein arginine methyltransferases (PRMTs). A novel mammalian hnRNP, E1B-AP5, recently identified by its interaction with adenovirus early protein E1B-55kDa, has been proposed to have a regulatory role in adenoviral and host-cell mRNA processing/nuclear export [Gabler, Schutt, Groitl, Wolf, Shenk and Dobner (1998) J. Virol. 72, 7960–7971]. Here we report that E1B-AP5 is methylated in vivo in its Arg-Gly-Gly (RGG)-box domain, known to mediate protein–RNA interactions. The activity responsible for E1B-AP5 methylation forms a complex with E1B-AP5 in vivo. The predominant mammalian arginine methyltransferase HRMT1L2 (hPRMT1) did not detectably methylate endogenous E1B-AP5 despite efficiently methylating a recombinant RGG-box domain of E1B-AP5. Using yeast two-hybrid screening we identified HRMT1L1 (PRMT2) as one of the proteins interacting with E1B-AP5. By in situ immunofluorescence we demonstrated that E1B-AP5 co-localizes with the nuclear fraction of HRMT1L1. The Src homology 3 (SH3) domain of HRMT1L1 was essential for its interaction with E1B-AP5 in vivo. We suggest that HRMT1L1 is responsible for specific E1B-AP5 methylation in vivo.
AU  - Kzhyshkowska, J.*
AU  - Schütt, H.*
AU  - Liss, M.*
AU  - Kremmer, E.
AU  - Stauber, R.*
AU  - Wolf, H.*
AU  - Dobner, T.*
C1  - 22181
C2  - 20885
SP  - 305-314
TI  - Heterogeneous nuclear ribonucleoprotein E1B-AP5 is methylated in its Arg-Gly-Gly (RGG) box and interacts with human arginine methyltransferase HRMT1L1.
JO  - Biochem. J.
VL  - 358
IS  - 2
PY  - 2001
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - 17β-Hydroxysteroid dehydrogenase (17β-HSD) from the filamentous fungus Cochliobolus lunatus (17β-HSDcl) catalyses the reduction of steroids and of several o- and p-quinones. After purification of the enzyme, its partial amino acid sequence was determined. A PCR fragment amplified with primers derived from peptide sequences was generated for screening the Coch. lunatus cDNA library. Three independent full-length cDNA clones were isolated and sequenced, revealing an 810-bp open reading frame encoding a 270-amino-acid protein. After expression in Escherichia coli and purification to homogeneity, the enzyme was found to be active towards androstenedione and menadione, and was able to form dimers of M(r) 60,000. The amino acid sequence of the novel 17β-HSD demonstrated high homology with fungal carbonyl reductases, such as versicolorin reductase from Emericella nidulans (Aspergillus nidulans; VerA) and Asp. parasiticus (Ver1), polyhydroxynaphthalene reductase from Magnaporthe grisea, the product of the Brn1 gene from Coch. heterostrophus and a reductase from Colletotrichum lagenarium, which are all members of the short-chain dehydrogenase/reductase superfamily. 17β-HSDcl is the first discovered fungal 17β-hydroxysteroid dehydrogenase belonging to this family. The primary structure of this enzyme may therefore help to elucidate the evolutionary history of steroid dehydrogenases.
AU  - Lanisnik Rizner, T.*
AU  - Moeller, G.
AU  - Thole, H.H.*
AU  - Žakelj-Mavrič, M.*
AU  - Adamski, J.
C1  - 33203
C2  - 35628
SP  - 425-431
TI  - A novel 17β-hydroxysteroid dehydrogenase in the fungus Cochliobolus lunatus: New insights into the evolution of steroid-hormone signalling.
JO  - Biochem. J.
VL  - 337
IS  - 3
PY  - 1999
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - GTP cyclohydrolase I catalyses the first and rate-limiting step of tetrahydrobiopterin biosynthesis. Its expression is regulated by interferon-γ or kit ligand in a tissue-specific manner. Three different cDNA forms have been reported for human GTP cyclohydrolase I. We have isolated, from a human liver cDNA library, two clones which contained inserts identical with two of the cDNAs reported by Togari et al. The three open reading frames corresponding to all reported cDNA sequences were expressed in Escherichia coli. Only the recombinant protein corresponding to the longest reading frame catalysed the conversion of GTP into dihydroneopterin triphosphate. The proteins corresponding to the shorter reading frames failed to catalyse not only the generation of dihydroneopterin triphosphate but also the release of formate from GTP, an intermediate step of the reaction. Recombinant human GTP cyclohydrolase I showed sigmoidal substrate kinetics and maximum activity at 60°C. These findings are well in line with the published properties of the enzyme isolated from rat liver. The data indicate that cytokine-mediated induction of GTP cyclohydrolase I is not due to the expression of enzyme isoforms.
AU  - Gütlich, M.
AU  - Jäger, E.
AU  - Rücknagel, K.P.
AU  - Werner, T.
AU  - Rödl, W.
AU  - Ziegler, I.
AU  - Bacher, A.
C1  - 40064
C2  - 0
SP  - 215-221
TI  - Human GTP cyclohydrolase I: Only one out of three cDNA isoforms gives rise to the active enzyme.
JO  - Biochem. J.
VL  - 302
IS  - 1
PY  - 1994
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - To evaluate the question of whether or not insulin activates protein kinase C (PKC), we compared the effects of insulin and phorbol esters on the phosphorylation of the PKC substrate, i.e. myristoylated alanine-rich C-kinase substrate (MARCKS). In rat adipocytes, rat soleus muscle and BC3H-1 myocytes, maximally effective concentrations of insulin and phorbol esters provoked comparable, rapid, 2-fold (on average), non-additive increases in the phosphorylation of immunoprecipitable MARCKS. These effects of insulin and phorbol esters on MARCKS phosphorylation in intact adipocytes and soleus muscles were paralleled by similar increases in the phosphorylation of an exogenous, soluble, 85 kDa PKC substrate (apparently a MARCKS protein) during incubation of post-nuclear membrane fractions in vitro. Increases in the phosphorylation of this 85 kDa PKC substrate in vitro were also observed in assays of both plasma membranes and microsomes obtained from rat adipocytes that had been treated with insulin or phorbol esters. These insulin-induced increases in PKC-dependent phosphorylating activities of adipocyte plasma membrane and microsomes were associated with increases in membrane contents of diacylglycerol, PKC-beta 1 and PKC-beta 2. Our findings suggest that insulin both translocates and activates PKC in rat adipocytes, rat soleus muscles and BC3H-1 myocytes.
AU  - Arnold, T.P.
AU  - Standaert, M.L.
AU  - Hernandez, H.
AU  - Watson, J.
AU  - Mischak, H.
AU  - Kazanietz, M.G.
AU  - Cooper, D.R.
AU  - Farese, R.V.
C1  - 20637
C2  - 13851
SP  - 155-164
TI  - Effects of insulin and phorbol esters on MARCKS (myristoylated alanine-rich C-kinase substrate) phosphorylation (and other parameters of protein kinase C activation) in rat adipocytes, rat soleus muscle and BC3H-1 myocytes.
JO  - Biochem. J.
VL  - 295
IS  - 1
PY  - 1993
SN  - 0264-6021
ER  - 

TY  - JOUR
AU  - Günzburg, W.H.
AU  - Salmons, B.
C1  - 19940
C2  - 13102
SP  - 625-632
TI  - Factors Controlling the Expression of Mouse Mammary Tumour Virus.
JO  - Biochem. J.
VL  - 283
IS  - 3
PY  - 1992
SN  - 0264-6021
ER  - 

TY  - JOUR
AU  - Lutz, W.D.
AU  - Stahl, B.U.
C1  - 19456
C2  - 12551
TI  - Dioxins and Ah receptor - one size fits all?
JO  - Biochem. J.
PY  - 1992
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - n fura-2-loaded A10 vascular smooth-muscle cells, 1 nM-vasopressin and 200 nM-endothelin evoked a rapid transient rise in intracellular free Ca2+ concentration [(Ca2+]i), which was then followed by a maintained elevation of [Ca2+]i. The maintained elevation of [Ca2+]i was only partially inhibited by 5 microM-nifedipine, but completely abolished in the presence of 1 mM-EGTA. When extracellular Ca2+ was replaced with 1 mM-Mn2+ (Mn2+ quenches fura-2 fluorescence), both endothelin and vasopressin evoked an Mn2+ quench of the fluorescence from the intracellularly trapped fura-2, even in the presence of 5 microM-nifedipine. These data suggest that both vasopressin and endothelin promote a bivalent-cation influx and provide further evidence for receptor-mediated Ca2+ entry in vascular smooth muscle.
AU  - Simpson, A.
AU  - Stampfl, A.
AU  - Ashley, C.
C1  - 18193
C2  - 11403
SP  - 277-280
TI  - Evidence for Receptor-Mediated Bivalent-Cation Entry in A10 Vascular Smooth-Muscle Cells.
JO  - Biochem. J.
VL  - 267
IS  - 1
PY  - 1990
SN  - 0264-6021
ER  - 

TY  - JOUR
AB  - Carbamates are a widely used class of insecticides and herbicides. They were tested for their ability to affect human blood platelet aggregation and arachidonic acid metabolism in platelets. (1) The herbicides of the carbamate type have no, or only little, influence up to a concentration of 100 μM; the carbamate insecticides, however, inhibit both aggregation and arachidonic acid metabolism in a dose- and time-dependent manner. (2) Carbaryl, the most effective compound, inhibits platelet aggregation and cyclo-oxygenase activity completely at 10 μM. The liberation of arachidonic acid from phospholipids and the lipoxygenase pathway are not affected, whereas the products of the cyclo-oxygenase pathway are drastically decreased. (3) By using [14C]carbaryl labelled in the carbamyl or in the ring moiety, it could be proved that the carbamyl residue binds covalently to platelet proteins. In contrast with acetylsalicylic acid, which acetylates only one protein, carbaryl carbamylates a multitude of platelet proteins. (4) One of the carbamylated proteins was found to be the platelet cyclo-oxygenase, indicating that carbaryl resembles in this respect acetylsalicylic acid, which is known to inhibit this enzyme specifically by acetylation.
AU  - Krug, H.F.
AU  - Hamm, U.
AU  - Berndt, J.
C1  - 42242
C2  - 36183
SP  - 103-110
TI  - Mechanism of inhibition of cyclo-oxygenase in human blood platelets by carbamate insecticides.
JO  - Biochem. J.
VL  - 250
IS  - 1
PY  - 1988
SN  - 0264-6021
ER  - 

TY  - JOUR
AU  - Oeding, V.
AU  - Schlegel, H.G.
C1  - 41122
C2  - 35720
SP  - 239-248
TI  - β ketothiolase from hydrogenomonas eutropha H16 and its significance in the regulation of poly β hydroxybutyrate metabolism.
JO  - Biochem. J.
VL  - 134
IS  - 1
PY  - 1973
SN  - 0264-6021
ER  -