Comparison of gel-based phosphoproteomic approaches to analyse scarce oviductal epithelial cell samples

Human fallopian tube proteome shows high coverage of mesenchymal stem cells associated proteins

We report the largest scale MS based proteome of human fallopian tube (hFT). Ribosome, cytoskeleton, and vesicle associated proteins showed high abundance in hFT. Extraordinary high coverage of MSCs associated proteins in the hFT proteome.

The object of this research was to report a draft proteome of human fallopian tube (hFT) comprises 5416 identified proteins, which could be considered as a physiological reference to complement Human Proteome Draft. The proteomic raw data and metadata were stored in an integrated proteome resources centre iProX (IPX00034300). This hFT proteome contains many hFT markers newly identified by mass spectrum. This hFT proteome comprises 660 high-, 3605 medium- and 1181 low-abundant proteins. Ribosome, cytoskeleton, vesicle and protein folding associated proteins showed obvious tendency to be higher abundance in hFT. The extraordinary high coverage of mesenchymal stem cells (MSCs)-associated proteins were identified in this hFT proteome, which highly supported that hFT should contain a plenty of MSCs.

Evaluation of SYPRO Ruby total protein stain for the normalization of two-dimensional Western blots

Due to post-translational modifications such as phosphorylation, proteins exist as distinct charge variants. Two-dimensional (2D) gel electrophoresis followed by immunoblotting enables the detection of these isoforms. For their accurate relative quantitation in different samples, a loading control is necessary to compensate for technical errors such as imprecise sample loading or transfer. The study reveals that the combinatory approach of SYPRO Ruby and chemiluminescence-based 2D Western blot analysis exhibits high linearity and excellent reproducibility and is applicable for limited sample amounts.

Principles and examples of gel-based approaches for phosphoprotein analysis

Methods for analyzing the phosphorylation status of proteins are essential to investigate in detail key cellular processes, including signal transduction and cell metabolism. The transience of this post-translational modification and the generally low abundance of phosphoproteins require specific enrichment and/or detection steps prior to analysis. Here, we describe three gel-based approaches for the analysis of differentially expressed phosphoproteins. These approaches comprise (1) the sequential fluorescence staining of two-dimensional (2-D) gels using Pro-Q(®) Diamond and SYPRO(®) Ruby dyes to visualize and quantify phosphoproteins in total cellular lysates as well as (2) affinity enrichment of phosphoproteins in conjunction with sequential fluorescence staining of the 2-D gels and (3) affinity enrichment of proteins prior to pre-electrophoretic fluorescence labeling and 2-D gel electrophoresis.