Phosphoproteomics identified Endofin, DCBLD2, and KIAA0582 as novel tyrosine phosphorylation targets of EGF signaling and Iressa in human cancer cells

• Published in: Proteomics (Weinheim) Vol. 7; no. 14; pp. 2384 - 2397
• Main Authors: Chen, Yunhao, Low, Teck-Yew, Choong, Lee-Yee, Ray, Rajarshi Sankar, Tan, Yee-Ling, Toy, Weiyi, Lin, Qingsong, Ang, Boon Keong, Wong, Chee Hong, Lim, Simin, Li, Bin, Hew, Choy-Leong, Sze, Newman Siu-Kwan, Druker, Brian J., Lim, Yoon-Pin
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-07-2007; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Cell Line, Tumor; cICAT; DCBLD2; EGF; Endofin; Epidermal Growth Factor - metabolism; Fundamental and applied biological sciences. Psychology; Humans; Intracellular Signaling Peptides and Proteins - chemistry; Intracellular Signaling Peptides and Proteins - metabolism; Iressa; Membrane Proteins - chemistry; Membrane Proteins - metabolism; Miscellaneous; Molecular Sequence Data; Neoplasms - metabolism; Neoplasms - pathology; Phosphoproteins - chemistry; Phosphoproteins - metabolism; Phosphotyrosine - metabolism; Proteins; Proteomics; Quinazolines - pharmacology; Serine Endopeptidases - chemistry; Serine Endopeptidases - metabolism; Signal Transduction - drug effects; Tandem Mass Spectrometry; Human; Tyrosine; Phosphorylation; Iressa; EGF; cICAT; Proteomics; Malignant tumor; Cancer; DCBLD2; Endofin
• ISSN: 1615-9853; 1615-9861
• DOI: 10.1002/pmic.200600968

With the completion of the human genome project, analysis of enriched phosphotyrosyl proteins from epidermal growth factor (EGF)‐induced phosphotyrosine proteome permits the identification of novel downstream substrates of the EGF receptor (EGFR). Using cICAT‐based LC‐MS/MS method, we identified and relatively quantified the tyrosine phosphorylation levels of 21 proteins between control and EGF‐treated A431 human cervical cancer cells. Of these, Endofin, DCBLD2, and KIAA0582 were validated to be novel tyrosine‐phosphorylation targets of EGF signaling and Iressa, a highly selective inhibitor of EGFR. In addition, EGFR activity was shown to be necessary for EGF‐induced localization of Endofin, an FYVE domain‐containing protein regulated by phosphoinositol lipid and engaged in endosome‐mediated receptor modulation. Although several groups have conducted phosphoproteomics of EGF signaling in recent years, our study is the first to identify and validate Endofin, DCBLD2, and KIAA0582 as part of a complex EGF phosphotyrosine signaling network. These novel data will provide new insights into the complex EGF signaling and may have implications on target‐directed cancer therapeutics.