(1996). Progress with Proteome Projects: Why all Proteins Expressed by a Genome Should be Identified and How To Do It. Biotechnology and Genetic Engineering Reviews: Vol. 13, No. 1, pp. 19-50.

Progress with Proteome Projects: Why all Proteins Expressed by a Genome Should be Identified and How To Do It

Oligomerization of receptor protein tyrosine kinases such as the epidermal growth factor receptor (EGFR) by their cognate ligands leads to activation of the receptor. Transphosphorylation of the receptor subunits is followed by the recruitment of signaling molecules containing src homology 2 (SH2) or phosphotyrosine interaction domains (PID). Additionally, several cytoplasmic proteins that may or may not associate with the receptor undergo tyrosine phosphorylation. To identify several components of the EGFR signaling pathway in a single step, we have immunoprecipitated molecules that are tyrosine phosphorylated in response to EGF and analyzed them by one-dimensional gel electrophoresis followed by mass spectrometry. Combining matrix-assisted laser desorption/ionization (MALDI) and nanoelectrospray tandem mass spectrometry (MS/MS) led to the identification of nine signaling molecules, seven of which had previously been implicated in EGFR signaling. Several of these molecules were identified from low femtomole levels of protein loaded onto the gel. We identified Vav-2, a recently discovered guanosine nucleotide exchange factor that is expressed ubiquitously, as a substrate of the EGFR. We demonstrate that Vav-2 is phosphorylated on tyrosine residues in response to EGF and associates with the EGFR in vivo. Binding of Vav-2 to the EGFR is mediated by the SH2 domain of Vav-2. In keeping with its ubiquitous expression, Vav-2 seems to be a general signaling molecule, since it also associates with the platelet-derived growth factor (PDGF) receptor and undergoes tyrosine phosphorylation in fibroblasts upon PDGF stimulation. The strategy suggested here can be used for routine identification of downstream components of cell surface receptors in mammalian cells.

https://www.pnas.org/content/pnas/97/1/179.full.pdf

Analysis of receptor signaling pathways by mass spectrometry: Identification of Vav-2 as a substrate of the epidermal and platelet-derived growth factor receptors

5 6 Introduction ........................... 2-D gel electrophoresis allows the creation of reference maps . . . . . . . . . . . 2-D reference maps as a tool for proteome studies ..................... Global quantitation of proteins . . . . . . Study of post-translational modifications “Vector Maps” of 2-D gels . . . . . . . . . . . “Shotgun” approaches to proteome analysis ............................... Analysis of protein heterogeneity . . . . Current challenges to 2-D technology Low copy number proteins . . . . . . . . . . Very basic and large proteins Optimal size for 2-D gels . . . . . . . . . . . . Sample preparation . . . . . . . . . . . . . . . . . . . Protein modifications resulting from electrophoresis ........................ Conclusions ........................... References ............................ . . . . . . . . 830

Current challenges and future applications for protein maps and post‐translational vector maps in proteome projects

Single-stranded DNA-binding proteins (SSBs) are required for repair, recombination and replication in all organisms. Eukaryotic SSBs are regulated by phosphorylation on serine and threonine residues. To our knowledge, phosphorylation of SSBs in bacteria has not been reported. A systematic search for phosphotyrosine-containing proteins in Streptomyces griseus by immunoaffinity chromatography identified bacterial SSBs as a novel target of bacterial tyrosine kinases. Since genes encoding protein-tyrosine kinases (PTKs) have not been recognized in streptomycetes, and SSBs from Streptomyces coelicolor (ScSSB) and Bacillus subtilis (BsSSB) share 38.7% identity, we used a B.subtilis protein-tyrosine kinase YwqD to phosphorylate two cognate SSBs (BsSSB and YwpH) in vitro. We demonstrate that in vivo phosphorylation of B.subtilis SSB occurs on tyrosine residue 82, and this reaction is affected antagonistically by kinase YwqD and phosphatase YwqE. Phosphorylation of B.subtilis SSB increased binding almost 200-fold to single-stranded DNA in vitro. Tyrosine phosphorylation of B.subtilis, S.coelicolor and Escherichia coli SSBs occured while they were expressed in E.coli, indicating that tyrosine phosphorylation of SSBs is a conserved process of post-translational modification in taxonomically distant bacteria.

/pdf/bacterial-single-stranded-dna-binding-proteins-are-52lesjx2u0.pdf

Bacterial single-stranded DNA-binding proteins are phosphorylated on tyrosine.

Determining the phosphorylation stoichiometry at specific sites in a phosphoprotein is a very challenging task. We describe here a novel mass spectrometry based method that is capable of measuring the absolute phosphorylation stoichiometry at specific sites without the need for specific internal standards, phospho-site antibodies or radioactivity. The method is based on a gentle chemical labeling strategy which specifically and differentially labels the N-terminus of all peptides in a sample with either a D(5)- or D(0)-propionyl group and measures the ratio of the abundance of the D(5)/D(0) peptide pairs simultaneously using mass spectrometry. Using matrix-assisted laser desorption/ionization (MALDI), the method can measure absolute stoichiometry to within at least 10% and can be applied to both in vitro and in vivo phosphorylated peptides and proteins. Furthermore, this method can potentially be applied to the quantitative study of other types of protein post-translational modifications, and the profiling of protein expression on the proteome level.

N-Terminal peptide labeling strategy for incorporation of isotopic tags: a method for the determination of site-specific absolute phosphorylation stoichiometry.

The activation of protein tyrosine kinase (PTKs) and subsequent tyrosine phosphorylation of cellular proteins is a critical initial signal in the response of eukaryotic cells to mitogens, differentiative signals, and other stimuli. A number of PTK substrates have been identified and many of these are components of signal transduction pathways that regulate cell function. However, the majority of proteins that are tyrosine-phosphorylated in response to receptor signaling remain unidentified. As some of these unidentified PTK substrates may also be signal-transducing proteins, their identification and functional characterization is an important objective towards understanding receptor signaling. We describe the development of a comprehensive and general process for the isolation and structural characterization of tyrosine-phosphorylated proteins. The method involves enrichment by anti-phosphotyrosine affinity chromatography, electrophoretic concentration and separation, and proteolytic fragmentation of individual purified phosphoproteins. Resulting peptide fragments are separated by microbore reverse-phase high performance liquid chromatography (RP-HPLC) and a portion of the eluted peptides are subjected to electrospray-mass spectrometry (ES/MS) for accurate determination of peptide masses. Proteolytic fragmentation of a protein produces a characteristic set of peptide masses that can be used to rapidly identify the protein by searching databases containing the peptide mass "fingerprints" for all known proteins. The identity of the protein established by this method can be confirmed by sequence analysis of selected peptides. We have applied this procedure to the analysis of PTK substrates from B lymphocytes that have been stimulated through the B cell antigen receptor (BCR). Signaling by this receptor is involved in the generation of antibodies against foreign molecules (antigens). The BCR activates multiple PTKs which phosphorylate at least 30 different proteins. We have identified several of these tyrosine-phosphorylated proteins, including Syk, a PTK that is known to be tyrosine-phosphorylated in activated B cells. Thus, the procedure described here can be used to identify regulatory proteins of low abundance. The process consists of a logical succession of compatible steps that avoids pitfalls inherent to prior attempts to characterize low abundance phosphoproteins and should find wide use for the identification of tyrosine-phosphorylated proteins in other cell types.

Purification and identification of tyrosine-phosphorylated proteins from B lymphocytes stimulated through the antigen receptor

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Daisy Vianzon

Author Tools

Chat about Author

Papers

Purification and identification of tyrosine-phosphorylated proteins from B lymphocytes stimulated through the antigen receptor