Post-translational modifications (PTMs) are employed in the cell to alter protein function, and typically involve small chemical changes on the surface of the protein. The dynamic enzyme-catalyzed process of adding or subtracting PTMs mediates signaling in the cell. In other words, PTMs enhance protein-protein communication, enabling the cell to respond to internal or external signals.

Researchers who run a lot of chromatin immunoprecipitation "ChIP" assays – maybe even your advisor – might subscribe to the idea that polyclonal antibodies perform better than monoclonal antibodies. But is that always actually true?

It’s worth your time to understand the differences between the two in terms of antigen recognition and specificity, and dispel some myths. 

Early exploration of unmapped biological signaling pathways were carried out using radiolabeled phospho-imaging. The development of phospho-specific antibodies to detect and quantify protein phosphorylation made life easier for researchers (less ³²P waste to deal with), but the interpretation of data from these experiments comes with its own set of caveats. 

 Part two of a four-part series on Immunofluorescence. Check out our posts on Validation and Fixation and Permeabilization. 

After months of hard work, your research has honed in on a hypothesis you can test with immunofluorescence (IF). You've chosen antibodies and performed pilot IF experiments (see The Importance of Validation), and the localization of the protein appears reasonable. But how can you be sure the IF data you've acquired represents real biological phenomena? We present two examples of experimental controls in this post.

Part 1 gave an overview on mass spectrometry-based proteomics. Now it’s time to talk about how this strategy can be used to identify peptides with post-translational modifications (PTM) from a complex biological sample.

After sequencing of the human genome was complete, it was time to roll up our sleeves and get started on the daunting task of unraveling the complexity of the proteome. Thus the era of proteomics, the study of the function of all expressed proteins, was born. This task is especially complicated

Part 1 and part 2 introduced mass spectrometry-based proteomic methods, like PTMScan^®, for the study of post-translational modifications (PTMs). In the final part of this series you can see how PTMScan can be applied in translational research.

Part 1 gave an overview on mass spectrometry-based proteomics. Now it’s time to talk about how this strategy can be used to identify peptides with post-translational modifications (PTM) from a complex biological sample.

After sequencing of the human genome was complete, it was time to roll up our sleeves and get started on the daunting task of unraveling the complexity of the proteome. Thus the era of proteomics, the study of the function of all expressed proteins, was born. This task is especially complicated because unlike the human genome, which is largely static in every cell, the proteome is different between say a liver cell and a brain cell, or between a healthy cell and a cancerous cell, or even between an individual cell at the different stages of development. To address this challenge the Human Proteome Project was founded. Its mission is to characterize all human genes by generating a map of the protein based molecular architecture of the body. In this way, it will become a resource to help elucidate the biological and molecular function of genes and facilitate the advanced diagnosis and treatment of disease.

Simplifying proteomics part 1 introduced mass spectrometry-based proteomics for profiling post-translational modifications (PTMs). Part 2 explained how you can go fishing for low abundance PTM peptides from a complex mixture using PTMScan.

If visualization is more your thing, it might be helpful to watch the PTMScan tutorial video to learn more about:

• How PTMScan employs PTM-sequence motif and PTM-specific antibodies to immunoenrich PTM-containing peptides before LC-MS/MS
• How you can use PTMScan services and kits from CST to study PTMs like phosphorylation, acetylation, ubiquitination, methylation, and succinylation
• The PTMScan service workflow from experimental design to data analysis