Christian Hedberg

Christian Hedberg
Umeå University | UMU · Department of Chemistry

About

105
Publications
8,374
Reads
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3,653
Citations
Citations since 2016
24 Research Items
1951 Citations
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300

Publications

Publications (105)
Article
Full-text available
To adapt to fluctuating protein folding loads in the endoplasmic reticulum (ER), the Hsp70 chaperone BiP is reversibly modified with adenosine monophosphate (AMP) by the ER-resident Fic-enzyme FICD/HYPE. The structural basis for BiP binding and AMPylation by FICD has remained elusive due to the transient nature of the enzyme-substrate-complex. Here...
Article
Full-text available
Legionella pneumophila infects eukaryotic cells by forming a replicative organelle – the Legionella containing vacuole. During this process, the bacterial protein DrrA/SidM is secreted and manipulates the activity and post-translational modification (PTM) states of the vesicular trafficking regulator Rab1. As a result, Rab1 is modified with an aden...
Article
Full-text available
AMPylation is a post-translational modification that modifies amino acid side chains with adenosine monophosphate (AMP). Recently, a role of AMPylation as a universal regulatory mechanism in infection and cellular homeostasis has emerged, driving the demand for universal tools to study this modification. Here, we describe three monoclonal anti-AMP...
Article
ATP and GTP are exceptionally important molecules in biology with multiple, and often discrete, functions. Therefore, enzymes that bind to either of them must develop robust mechanisms to selectively utilize one or the other. Here, this specific problem is addressed by molecular studies of the human NMP kinase AK3 which uses GTP to phosphorylate AM...
Article
Full-text available
Various pathogenic bacteria use post-translational modifications to manipulate the central components of host cell functions. Many of the enzymes released by these bacteria belong to the large Fic family, which modify targets with nucleotide monophosphates. The lack of a generic method for identifying the cellular targets of Fic family enzymes hind...
Preprint
Full-text available
AMPylation is a post-translational modification that modifies amino acid side chains with adenosine monophosphate (AMP). Recent progress in the field reveals an emerging role of AMPylation as a universal regulatory mechanism in infection and cellular homeostasis, however, generic tools to study AMPylation are required. Here, we describe three monoc...
Article
Background and aims: Small-molecule flux in tissue microdomains is essential for organ function, but knowledge of this process is scant due to the lack of suitable methods. We developed two independent techniques that allow the quantification of advection (flow) and diffusion in individual bile canaliculi and in interlobular bile ducts of intact l...
Article
Full-text available
The causative agent of Legionnaires disease, Legionella pneumophila , translocates the phosphocholine transferase AnkX during infection and thereby posttranslationally modifies the small guanosine triphosphatase (GTPase) Rab1 with a phosphocholine moiety at S76 using cytidine diphosphate (CDP)–choline as a cosubstrate. The molecular basis for Rab1...
Preprint
Small-molecule flux in tissue-microdomains is essential for organ function, but knowledge of this process is scant due to the lack of suitable methods. We developed two independent techniques that allow the quantification of advection (flow) and diffusion in individual bile canaliculi and in interlobular bile ducts of intact livers in living mice,...
Article
Site‐specific protein functionalisation has become an indispensable tool in modern life sciences. Here, tag based enzymatic protein functionalisation techniques are among the most versatile applicable approaches. However many chemo enzymatic functionalisation strategies suffer from a low substrate scope of utilized enzymes for functional labeling p...
Article
Colibactin is a small molecule produced by certain bacterial species of the human microbiota that harbour the pks genomic island. Pks+ bacteria induce a genotoxic phenotype in eukaryotic cells and have been linked with colorectal cancer progression. Colibactin is produced in a benign prodrug form which, prior to export, is enzymatically matured by...
Article
Colibactin is a small molecule produced by certain bacterial species of the human microbiota that harbour the pks genomic island. Pks+ bacteria induce a genotoxic phenotype in eukaryotic cells and have been linked with colorectal cancer progression. Colibactin is produced in a benign prodrug form which, prior to export, is enzymatically matured by...
Article
The present study describes the synthesis and biological studies of a small series of head‐to‐tail cyclic tetrapeptides of the general structure c(Lys‐β2,2‐Xaa‐Lys) containing one lipophilic β2,2‐amino acid and Lys, Gly, Ala, or Phe as the Xaa residue in the sequence. The peptides were investigated for antimicrobial activity against gram‐positive a...
Article
The site-selective incorporation of fluorescent amino acids into proteins has emerged as a valuable alternative to expressible protein reporters. For successful application, a robust and scalable yet flexible route to non-natural amino acids is required. This work describes an improved synthesis of coumarin-conjugated lysine derivatives where fluor...
Article
Full-text available
Significance As a prerequisite for life, enzymes enhance the rate constants of chemical reactions that otherwise would be orders-of-magnitude too slow. One of the challenges facing enzymes is recognition of correct substrates in the complex and multifaceted cellular environment. This is especially true when distinction must be made between substrat...
Article
Incorporation of the fluorogenic l-(7-hydroxycoumarin-4-yl)ethylglycine into proteins is a valuable biological tool. Coumarins are typically accessed via the Pechmann reaction, which requires acidic conditions and lacks substrate flexibility. A Pd-mediated coupling is described between o-methoxyboronic acids and a glutamic acid derived (Z)-vinyl tr...
Article
Neutrophils are short-lived leukocytes that migrate to sites of infection as part of the acute immune response where they phagocytose, degranulate and form Neutrophil Extracellular Traps (NETs). During NET formation, the nuclear lobules of neutrophils disappear, the chromatin expands and, accessorized with neutrophilic granule proteins, is expelled...
Article
The intracellular pathogen Legionella pneumophila infects lung macrophages and injects numerous effector proteins into the host cell to establish a vacuole for proliferation. The necessary interference with vesicular trafficking of the host is achieved by modulation of the function of Rab GTPases. The effector protein AnkX chemically modifies Rab1b...
Article
Woodward's reagent K (WRK) is a reactive heterocyclic compound that has been employed in protein chemistry to covalently and unspecifically label proteins at nucleophilic amino acids, notably at histidine and cysteine. We have developed a panel of WRK-derived activity-based probes and show that surprisingly and unexpectedly, these probes are fairly...
Article
Woodward's reagent K (WRK) is a reactive heterocyclic compound that has been employed in protein chemistry to covalently and unspecifically label proteins at nucleophilic amino acids, notably at histidine and cysteine. We have developed a panel of WRK-derived activity-based probes and show that surprisingly and unexpectedly, these probes are fairly...
Article
Full-text available
Small molecule signaling promotes the communication between bacteria as well as between bacteria and eukaryotes. The opportunistic pathogenic bacterium Legionella pneumophila employs LAI-1 (3-hydroxypentadecane-4-one) for bacterial cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, which regulates...
Data
Effect of LAI-1 on L. pneumophila uptake or cytotoxicity. (A) D. discoideum or (B) RAW 264.7 macrophages were left uninfected or infected (MOI 10, 1 h) with L. pneumophila wild-type or ΔicmT harboring pCR76 (GFP) and treated with LAI-1 (1, 5 or 10 μM, 1 h). DMSO treatment was used as control. Uptake efficiency was determined by flow cytometry (GFP-...
Data
LAI-1-dependent inhibition of cell migration does not require Ran or CD2AP. Confluent cell layers of A549 cells were left untreated or treated for 2 days with siRNA against (A) the small GTPase Ran or its effector RanBP1, or (B, C) the SH3-domain scaffold protein CDAP2, incubated with LAI-1 (10 μM, 1h) or not, scratched and let migrate for 24 h. De...
Data
LAI-1 does not affect co-localization of L. pneumophila with Cdc42 or IQGAP1. A549 cells were infected (MOI 10, 1 h) with L. pneumophila wild-type or ΔicmT mutant bacteria harboring plasmid pSW001 (DsRed) and treated with LAI-1 (10 μM, 1 h), fixed and stained with antibodies against IQGAP1 or Cdc42 (green). The cellular localization of IQGAP1 or Cd...
Data
Selected D. discoideum genes differentially regulated by LAI-1. (DOCX)
Data
Oligonucleotides used for RNA interference. (DOCX)
Data
Primer pairs used for quantitative real-time PCR analysis. (DOCX)
Data
Synthesis of LAI-1 and amino-LAI-1. (DOCX)
Data
Quantification of microtubules and scratch wound closure. (A) RAW 264.7 macrophages treated with LAI-1 (10 μM, 1 h) or not were immuno-labeled for α-tubulin (green), and microtubule fibers per cell were counted along cross-sections (left panel, yellow lines). The 4 graphs (right panel) depict the relative fluorescence intensity (arbitrary units, AU...
Data
Analysis of siRNA depletion efficiency by Western blots. The efficiency of siRNA depletion (mixture of 4 different oligonucleotides) was assessed by Western blot using (A) antibodies corresponding to the targets indicated or (B) antibodies against Cdc42, Rac1 or IQGAP1 corresponding to possible off-targets of ARHGEF9-directed siRNA. (TIF)
Data
All D. discoideum genes differentially regulated by LAI-1. (DOCX)
Data
LAI-1 promotes inactivation but does not alter phosphorylation of Cdc42. A549 cells were treated with LAI-1 (10 μM, 1 h) or not, and (A, B, D) lysed or (C) fixed. (A) Pull down with an antibody specifically recognizing Cdc42(GTP) and protein A/G agarose. The amount of active Cdc42 was analyzed by Western blot using an antibody recognizing Cdc42(GTP...
Data
LAI-1-mediated gene regulation in D. discoideum. (A) Pie diagram of functionally categorised D. discoideum genes up- or down-regulated by 20 μM LAI-1. This concentration of LAI-1 led to robust changes in gene regulation, without being toxic to the amoebae. Shown are the absolute numbers of genes in different categories according to the yeast classi...
Data
LAI-1 reverses Icm/Dot-dependent inhibition of migration by L. pneumophila. (A) D. discoideum Ax3 amoebae harboring pSW102 (GFP) or (C) RAW 264.7 macrophages were infected (MOI 10, 1 h) with L. pneumophila wild-type or ΔicmT mutant bacteria and treated with LAI-1 (10 μM, 1 h) or not. Single cell migration towards folate (1 mM) or CCL5 (100 ng/ml) w...
Data
Depletion of Cdc42 or IQGAP1 does not affect intracellular replication of L. pneumophila. A549 cells were treated with a mixture of 4 different siRNAs against either Cdc42 or IQGAP1 for 2 days and infected with L. pneumophila wild-type or ΔicmT mutant bacteria harboring pCR76 (GFP). Fluorescence was measured at different timepoints post-infection (...
Article
The causative agent of Legionnaires' disease, Legionella pneumophila, employs the autoinducer compound LAI-1 (3-hydroxypentadecane-4-one) for cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, comprising the autoinducer synthase LqsA, the sensor kinases LqsS and LqsT, as well as the response regul...
Article
We present a new protein labeling method based on the covalent enzymatic phosphocholination of a specific octapeptide amino acid sequence in intact proteins. The bacterial enzyme AnkX from Legionella pneumophila has been established to transfer functional phosphocholine moieties from synthetically produced CDP-choline derivatives to N-termini, C-te...
Article
Wir präsentieren eine neue Methode zur Proteinmarkierung, die auf der kovalenten enzymatischen Phosphocholinierung einer spezifischen Octapeptidsequenz intakter Proteine beruht. Das Enzym AnkX aus Legionellen wurde etabliert, um funktionalisierte Phosphocholingruppen aus synthetischen CDP-Cholin-Derivaten auf N- und C-Termini, sowie interne Schleif...
Article
The first total synthesis of the title compounds [A (Ia) and B (Ib)] from phenol derivative is reported in 7.2% and 4.3% overall yields, respectively.
Article
Full-text available
Resistance towards CD95-mediated apoptosis is a hallmark of many different malignancies, like it is known from primary chronic lymphocytic leukemia (CLL) cells. Previously, we could show that miR-138 and -424 are down-regulated in CLL cells. Here, we identified two new target genes, namely acyl protein thioesterase (APT) 1 and 2, which are under co...
Article
Full-text available
The first total synthesis of breitfussin A and B is described. The approach features two palladium-catalyzed cross-couplings installing the indole and pyrrole onto the oxazole core and selective lithiation/iodination of a common indole-oxazole fragment providing 2,4-diiodinated or 2-iodinated oxazoles as potential precursors for breitfussin A and B...
Article
In the cell, proteins are frequently modified covalently at specific amino acids with post-translational modifications, leading to a diversification of protein functions and activities. Since the introduction of high-resolution mass spectrometry, new posttranslational modifications are constantly being discovered. One particular modification is the...
Conference Paper
Introduction: Resistance towards CD95-mediated apoptosis is a hallmark of many different malignancies, like it is known from primary chronic lymphocytic leukemia (CLL) cells. Moreover, apoptosis mediated through CD95 is an essential mechanism to eliminate e.g. auto-reactive or virally infected cells. However, its mode of action is still not fully u...
Article
Full-text available
Aim: To investigate the role of acyl-CoA synthetase 5 (ACSL5) activity in Wnt signaling in intestinal surface epithelia. Methods: Several cell lines were used to investigate the ACSL5-dependent expression and synthesis of Wnt2B, a mitochondrially expressed protein of the Wnt signaling family. Wnt activity was functionally assessed with a lucifer...
Chapter
Posttranslational modification (PTM) with functional groups is a universal mechanism for diversifying the activities of proteins. PTMs can affect many properties of proteins, such as localization, activity status, interaction networks, solubility, folding, turnover, or stability. This chapter describes the process of PTM identification using the ad...
Chapter
Full-text available
This chapter describes the combination of bioinformatics, organic synthesis, in vitro inhibition studies, and live-cell imaging (microscopy) to elucidate the function of acyl protein thioesterase 1 (APT1) in regulation of protein palmitoylation. APT1 critically influences the localization and function of several palmitoylated peripheral membrane pr...
Article
Despite their structural similarity, the natural products omuralide and vibralactone have different biological targets. While omuralide blocks the chymotryptic activity of the proteasome with an IC50 value of 47 nM, vibralactone does not have any effect at this protease up to a concentration of 1mM. Activity-based protein profiling in HeLa cells re...
Article
Full-text available
The localization and signaling of S-palmitoylated peripheral membrane proteins is sustained by an acylation cycle in which acyl protein thioesterases (APTs) depalmitoylate mislocalized palmitoylated proteins on endomembranes. However, the APTs are themselves reversibly S-palmitoylated, which localizes thioesterase activity to the site of the antago...
Article
Trotz der strukturellen Ähnlichkeit der beiden Naturstoffe Omuralid und Vibralacton zeigen sich unerwartete Unterschiede in den Präferenzen ihrer jeweiligen Zielenzyme. Während Omuralid das Chymotrypsin‐ähnliche aktive Zentrum des Proteasoms mit IC50 = 47 nM inhibiert, hat Vibralacton auch bei Konzentrationen von bis zu 1 mM keinen Effekt auf diese...
Article
Editing the translations: Adenylylation and phosphocholination have recently been found as important post-translational modifications used by pathogenic bacteria during the infection process. This review discusses the combined use of chemical handles and specific antibodies for the identification of previously unknown substrates of these post-trans...
Conference Paper
Introduction CD95-mediated apoptosis is a central physiologic mechanism to eliminate e.g. auto-reactive and malignant cells. However, its mode of action remains still not fully understood. Recently, it could be shown that palmitoylation of CD95 alters its apoptotic function. However, the role, regulation and precise molecular function of palmitoyla...
Article
Full-text available
Legionella pneumophila is a ubiquitous fresh-water bacterium which reproduces within its erstwhile predators, environmental amoeba, by subverting the normal pathway of phagocytosis and degradation. The molecular mechanisms which confer resistance to amoeba are apparently conserved and also allow replication within macrophages. Thus, L. pneumophila...
Article
Full-text available
In eukaryotic organisms, cysteine palmitoylation is an important reversible modification that impacts protein targeting, folding, stability, and interactions with partners. Evidence suggests that protein palmitoylation contributes to key biological processes in Apicomplexa with the recent palmitome of the malaria parasite Plasmodium falciparum repo...
Article
Catch me if you can! The ClpP protease mediates protein homeostasis and can be efficiently inhibited by β-lactones. A combination of molecular docking, mutagenesis, activity-based protein profiling, and kinetics studies now reveals the mechanism of ClpP inhibition. A hydrophobic pocket next to the active site allows binding of long aliphatic and ar...
Article
Identification and confirmation of bioactive small-molecule targets is a crucial, often decisive step both in academic and pharmaceutical research. Through the development and availability of several new experimental techniques, target identification is, in principle, feasible, and the number of successful examples steadily grows. However, a generi...
Article
Die Identifizierung und Validierung von Zielmolekülen biologisch aktiver niedermolekularer Verbindungen ist ein äußerst wichtiger, oft maßgebender Schritt in der akademischen und pharmazeutischen Forschung. Dank der Entwicklung und der Verfügbarkeit diverser neuer experimenteller Verfahren ist die Identifizierung von Zielmolekülen prinzipiell reali...
Article
Catch me if you can! Die ClpP-Protease ist ein integraler Bestandteil der Protein-Homöostase und kann effizient durch β-Lactone gehemmt werden. Eine Kombination aus molekularem Modelling, Mutagenese und Kinetikstudien enthüllt jetzt den Mechanismus der ClpP-Inhibition: Eine hydrophobe Tasche neben dem aktiven Zentrum ermöglicht die Bindung von alip...
Article
In the third place: Inspired by the tetrahydroisoquinoline (THIQ) alkaloid noscapine, inhibitors of tubulin polymerization that bind to a site different from the colchicine and the vinca alkaloid binding sites have been synthesized. One compound is more potent than noscapine in HeLa cells and can overcome resistance to chemotherapeutics.
Article
Phosphocholination of eukaryotic host cell proteins has recently been identified as a novel post-translational modification important for bacterial pathogenesis. Here, we describe the first straightforward synthesis strategy for peptides containing phosphocholinated serine, threonine or tyrosine residues, using pre-formed functional amino acid buil...
Article
Full-text available
Although the addition of a 5'adenosine phosphodiester group to proteins, called adenylylation, has been known for decades, recently the possibility that adenylylation could be a molecular switch in cellular signalling pathways has emerged. The distinct mass shift upon adenylation of threonine or tyrosine residues renders it a good target for mass s...
Article
Ras proteins are of importance in cell proliferation, and hence their mutated forms play causative roles in many kinds of cancer in different tissues. Inhibition of the Ras-depalmitoylating enzyme acyl protein thioesterases APT1 and -2 is a new approach to modulating the Ras cycle. Here we present boronic and borinic acid derivatives as a new class...
Article
Modulation of protein-protein interactions (PPIs) is a highly demanding, but also a very promising approach in chemical biology and targeted drug discovery. In contrast to inhibiting PPIs with small, chemically tractable molecules, stabilisation of these interactions can only be achieved with complex natural products, like rapamycin, FK506, taxol,...
Article
Full-text available
Metastasis from primary tumors remains a major problem for tumor therapy. In the search for markers of metastasis and more effective therapies, the tumor metabolome is relevant because of its importance to the malignant phenotype and metastatic capacity of tumor cells. Altered choline metabolism is a hallmark of cancer. More specifically, a decreas...