Andreas Oliver HelbigSickKids · Program in Developmental and Stem Cell Biology Research
Andreas Oliver Helbig
PhD
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16
Publications
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Introduction
My main interests lie in signal transduction networks and their analysis. I employ various global proteomics strategies as well as targeted approaches such as MRM and IP-MS.
At the moment I am focusing on phosphorylation networks driving cancer development and suppression as well as signaling events determining development and lineage specification of embryonic stem cells.
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Publications
Publications (16)
Embryonic Stem Cell (ESC) differentiation requires complex cell signalling network dynamics, although the key molecular events remain poorly understood. Here, we use phosphopro-teomics to identify an FGF4-mediated phosphorylation switch centred upon the key Ephrin receptor EPHA2 in differentiating ESCs. We show that EPHA2 maintains pluripotency and...
While phospho-proteomics studies have shed light on the dynamics of cellular signaling, they mainly describe global effects and rarely explore mechanistic details, such as kinase/substrate relationships. Tools and databases, such as NetworKIN and PhosphoSitePlus, provide valuable regulatory details on signaling networks but rely on prior knowledge....
During cell division, microtubules organize a bipolar spindle to drive accurate chromosome segregation to daughter cells. Microtubules are nucleated by the γ-TuRC, a γ-tubulin complex that acts as a template for microtubules with 13 protofilaments. Cells lacking γ-TuRC core components do nucleate microtubules; however, these polymers fail to form b...
To establish more advanced models of molecular dynamics within cells, protein characteristics such as turnover rate and absolute instead of relative abundance have to be analyzed. We applied a proteomics strategy to analyze protein degradation and abundance in Saccharomyces cerevisiae. We used steady-state chemostat cultures to ascertain well-defin...
Table S3. Posphorylated peptides. displays quantified phosphorylated peptides from the WT and nat3Δ.
Table S6. In-silico digestion. shows detectable N-terminal peptides after in-silico digestion using trypsin or Lys-N.
Table S1. N-acetylation. displays an inventory of acetylated protein N-termini in S. cerevisiae.
Table S2. Protein levels. displays 15N/14N isotopic ratios of protein levels comparing WT and nat3Δ.
Table S4. NatB substrates. displays an inventory of detected NatB substrates.
Table S5. Protein variants. displays an inventory of detected protein variants.
The addition of an acetyl group to protein N-termini is a widespread co-translational modification. NatB is one of the main N-acetyltransferases that targets a subset of proteins possessing an N-terminal methionine, but so far only a handful of substrates have been reported. Using a yeast nat3Δ strain, deficient for the catalytic subunit of NatB, w...
N-terminal processing of proteins is a process affecting a large part of the eukaryotic proteome. Although N-terminal processing is an essential process, not many large inventories are available, in particular not for human proteins. Here we show that by using dedicated mass spectrometry-based proteomics techniques it is possible to unravel N-termi...
The analysis of proteins in biological membranes forms a major challenge in proteomics. Despite continuous improvements and the development of more sensitive analytical methods, the analysis of membrane proteins has always been hampered by their hydrophobic properties and relatively low abundance. In this review, we describe recent successful strat...
To investigate the effect of anaerobiosis on the Saccharomyces cerevisiae mitochondrial proteome and the formation of respiratory chain and other protein complexes, we analyzed mitochondrial protein extracts that were enriched from lysates of aerobic and anaerobic steady-state chemostat cultures. We chose an innovative approach in which native mito...
The analysis of proteome-wide phosphorylation events is still a major analytical challenge because of the enormous complexity of protein phosphorylation networks. In this work, we evaluate the complementarity of Lys-N, Lys-C, and trypsin with regard to their ability to contribute to the global analysis of the phosphoproteome. A refined version of l...
In proteomics multi-dimensional fractionation techniques are widely used to reduce the complexity of peptide mixtures subjected to mass spectrometric analysis. Here, we describe the sequential use of strong cation exchange and reversed phase liquid chromatography in the separation of peptides generated by a relatively little explored metallo-endope...