Premium
Crosstalk between Src and major vault protein in epidermal growth factor‐dependent cell signalling
Author(s) -
Kim Euikyung,
Lee Seunghwan,
Mian Md Firoz,
Yun Sang Uk,
Song Minseok,
Yi KyeSook,
Ryu Sung Ho,
Suh PannGhill
Publication year - 2006
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05112.x
Subject(s) - proto oncogene tyrosine protein kinase src , sh3 domain , microbiology and biotechnology , epidermal growth factor , sh2 domain , biology , tyrosine kinase , phosphorylation , tyrosine protein kinase csk , signal transduction , biochemistry , receptor
Vaults are highly conserved, ubiquitous ribonucleoprotein (RNP) particles with an unidentified function. For the three protein species (TEP1, VPARP, and MVP) and a small RNA that comprises vault, expression of the unique 100‐kDa major vault protein (MVP) is sufficient to form the basic vault structure. To identify and characterize proteins that interact with the Src homology 2 (SH2) domain of Src and potentially regulate Src activity, we used a pull‐down assay using GST–Src–SH2 fusion proteins. We found MVP as a Src–SH2 binding protein in human stomach tissue. Interaction of Src and MVP was also observed in 253J stomach cancer cells. A subcellular localization study using immunofluorescence microscopy shows that epidermal growth factor (EGF) stimulation triggers MVP translocation from the nucleus to the cytosol and perinuclear region where it colocalizes with Src. We found that the interaction between Src and MVP is critically dependent on Src activity and protein (MVP) tyrosyl phosphorylation, which are induced by EGF stimulation. Our results also indicate MVP to be a novel substrate of Src and phosphorylated in an EGF‐dependent manner. Interestingly, purified MVP inhibited the in vitro tyrosine kinase activity of Src in a concentration‐dependent manner. MVP overexpression downregulates EGF‐dependent ERK activation in Src overexpressing cells. To our knowledge, this is the first report of MVP interacting with a protein tyrosine kinase involved in a distinct cell signalling pathway. It appears that MVP is a novel regulator of Src‐mediated signalling cascades.