An integrated comparative phosphoproteomic and bioinformatic approach reveals a novel class of MPM-2 motifs upregulated in EGFRvIII-expressing glioblastoma cells.

TitleAn integrated comparative phosphoproteomic and bioinformatic approach reveals a novel class of MPM-2 motifs upregulated in EGFRvIII-expressing glioblastoma cells.
Publication TypeJournal Article
Year of Publication2009
AuthorsJoughin, BA, Naegle, KM, Huang, PH, Yaffe, MB, Lauffenburger, DA, White, FM
JournalMol Biosyst
Volume5
Issue1
Pagination59-67
Date Published2009 Jan
ISSN1742-2051
KeywordsAmino Acid Motifs, Antibodies, Antibody Specificity, Antigens, Cell Line, Tumor, Computational Biology, Glioblastoma, Humans, Phosphoproteins, Receptor, Epidermal Growth Factor, Up-Regulation
Abstract

Glioblastoma (GBM, WHO grade IV) is an aggressively proliferative and invasive brain tumor that carries a poor clinical prognosis with a median survival of 9 to 12 months. In a prior phosphoproteomic study performed in the U87MG glioblastoma cell line, we identified tyrosine phosphorylation events that are regulated as a result of titrating EGFRvIII, a constitutively active mutant of the epidermal growth factor receptor (EGFR) associated with poor prognosis in GBM patients. In the present study, we have used the phosphoserine/phosphothreonine-specific antibody MPM-2 (mitotic protein monoclonal #2) to quantify serine/threonine phosphorylation events in the same cell lines. By employing a bioinformatic tool to identify amino acid sequence motifs regulated in response to increasing oncogene levels, a set of previously undescribed MPM-2 epitope sequence motifs orthogonal to the canonical "pS/pT-P" motif was identified. These motifs contain acidic amino acids in combinations of the -5, -2, +1, +3, and +5 positions relative to the phosphorylated amino acid. Phosphopeptides containing these motifs are upregulated in cells expressing EGFRvIII, raising the possibility of a general role for a previously unrecognized acidophilic kinase (e.g. casein kinase II (CK2)) in cell proliferation downstream of EGFR signaling.

DOI10.1039/b815075c
Alternate JournalMol Biosyst
PubMed ID19081932
PubMed Central IDPMC2701618
Grant ListR01 CA096504-07 / CA / NCI NIH HHS / United States
R01 CA096504-09 / CA / NCI NIH HHS / United States
R01 CA118705-01A2 / CA / NCI NIH HHS / United States
R01 GM060594-08 / GM / NIGMS NIH HHS / United States
R01-CA96504 / CA / NCI NIH HHS / United States
R01-GM60594 / GM / NIGMS NIH HHS / United States
U54 CA112967-05 / CA / NCI NIH HHS / United States
U54-CA112967 / CA / NCI NIH HHS / United States