Insulin resistance is associated with an overall decrease in tyrosine phosphorylation and increased serine phosphorylation of IRS-1. To understand the role that the phosphorylation of IRS-1 serine residues may play in insulin resistance and diabetes we need to i) identify the location of serine phosphorylation sites of IRS-1 and ii) measure the site-specific changes in IRS-1 phosphoserine and phosphotyroserine levels between normal and insulin resistant conditions. Because of the complexity and insensitivity of existing methods for measuring serine phosphorylations, a major aim of this project is to develop a sensitive a robust protocol that is specific to peptides from protein enzyme digests containing serine phosphorylations. Phosphoserine residues will be selectively labeled with either an unlabeled or labeled reagent using a recently report4ed methodology. This modification will then permit the isolation of phosphoserine residues with the addition of a biotin tag and affinity purification. This reagent also contains a cleavable linker to facilitate the release of the enriched peptide from the solid support. During this research training fellowship, I will develop and apply this methodology along with muLC-MS/MS to both locate and quantify the serine phosphorylation sites of IRS-1 associated with insulin resistance.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32DK059731-02
Application #
6517936
Study Section
Special Emphasis Panel (ZRG1-BMT (01))
Program Officer
Hyde, James F
Project Start
2002-04-01
Project End
Budget Start
2002-04-01
Budget End
2003-03-31
Support Year
2
Fiscal Year
2002
Total Cost
$38,320
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92037
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Wu, Christine C; MacCoss, Michael J; Mardones, Gonzalo et al. (2004) Organellar proteomics reveals Golgi arginine dimethylation. Mol Biol Cell 15:2907-19
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MacCoss, Michael J; Wu, Christine C; Yates 3rd, John R (2002) Probability-based validation of protein identifications using a modified SEQUEST algorithm. Anal Chem 74:5593-9
Wu, Christine C; MacCoss, Michael J (2002) Shotgun proteomics: tools for the analysis of complex biological systems. Curr Opin Mol Ther 4:242-50
Anderson, Lorraine B; Maderia, Melissa; Ouellette, Anthony J A et al. (2002) Posttranslational modifications in the CP43 subunit of photosystem II. Proc Natl Acad Sci U S A 99:14676-81
MacCoss, Michael J; McDonald, W Hayes; Saraf, Anita et al. (2002) Shotgun identification of protein modifications from protein complexes and lens tissue. Proc Natl Acad Sci U S A 99:7900-5

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