Projekt Nr. 04

Identification and quantification of post-translational modifications

 

Phosphorylation is a key modulator of protein function. It is required for the control of many cellular processes such as signal transduction, cell cycle progression, gene expression, cell growth and differentiation.

It is estimated that approximately one third of all proteins in a eukaryotic cell are phosphorylated at any given time.

To understand these processes at the molecular level it is necessary to identify the phosphoproteins and their phosphorylation sites, and to quantify temporal and conditional changes of this protein modification.

 

State of the art

We already have established an IMAC method in which we use samples of methylesterified peptides to reduce non-specific binding of unphosphorylated peptides. By using either deuterated or normal methanol in the esterification reaction, we plan to use this approach for relative quantification of phosphopeptides in two different samples. Additionally, we will test alternative isotopic labelling methods and will proceed with testing of different stationary chromatographic phases to enrich for phosphopeptides.

 

Goal

Our group will focus on different strategies to improve the sensitivity of phosphorylation site analysis on a large scale and to combine it with quantitative methods. Further, we will develop new mass spectrometry methods using Fourier Transform Ion Cyclotron Resonance Mass Spectrometers (FT-ICR-MS). Additionaly we will develop new software tools for Proteome-Bioinformatics.

 

Solution
  1. Enrichment of phosphopeptides from complex mixtures by  Immobilized Metal-ion Affinity Chromatography (IMAC)
  2. Enrichment of phosphopeptides by substituting the phosphate moiety with a chemical affinity tag
  3. Application of neutral loss and precursor ion scan
  4. Analysis of intact proteins by top-down protein sequencing

 


Significance for the economy

Development of a new softwaretool.

 

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