Michael F Albers

Umeå University | UMU · Chemical Biological Centre

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...

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...

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...

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...

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-...

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...

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...

Selected D. discoideum genes differentially regulated by LAI-1. (DOCX)

Oligonucleotides used for RNA interference. (DOCX)

Primer pairs used for quantitative real-time PCR analysis. (DOCX)

Synthesis of LAI-1 and amino-LAI-1. (DOCX)

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...

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)

All D. discoideum genes differentially regulated by LAI-1. (DOCX)

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...

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...

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...

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 (...

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...

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...

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...

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...

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...

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...

The first straightforward building block based (non-interassembly) synthesis of peptides containing adenylylated serine and threonine residues is described. Key features include final global acidolytic protective group removal as well as full compatibility with standard Fmoc solid-phase peptide synthesis (SPPS). The described Thr-AMP SPPS-building...

Das Enzym DrrA des human-pathogenen Bakteriums Legionella pneumophila adenylyliert spezifisch einen Tyrosinrest der GTPase Rab1. Eine effiziente Syntheseroute unter Anwendung der Fmoc-Peptid-Festphasensynthese fuhrte zu Tyr-adenylylierten Peptiden und ermoglichte die Erzeugung monoselektiver polyklonaler Antikorper gegen diese posttranslationale Mo...

The enzyme DrrA of the human pathogen Legionella pneumophila adenylylates specifically a tyrosine of the GTPase Rab1. An efficient synthesis route using Fmoc solid phase peptide synthesis led to Tyr-adenylylated peptides and allowed the generation of mono-selective polyclonal antibodies against this post-translational modification.