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Polyamines regulate integrin mediated signaling during IEC‐6 cell attachment and spreading
Author(s) -
Elias Bertha C.,
Ray Ramesh M.,
Johnson Leonard R.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.979.2
Subject(s) - microbiology and biotechnology , autophosphorylation , integrin , polyamine , focal adhesion , cell migration , fibronectin , chemistry , cell adhesion , proto oncogene tyrosine protein kinase src , signal transduction , cell , kinase , biology , biochemistry , protein kinase a
Polyamines have been shown to play a pivotal role in normal cellular processes including cell division, migration and apoptosis. Migration is a two‐step process that consists of cell attachment followed by spreading. Cells depleted of polyamines are slow to attach and spread during integrin β3 activation, however the signaling mechanism involved is still unclear. In this study, we have examined the role of polyamines in the signaling process. Rat intestinal epithelial cells (IEC‐6) were plated on fibronectin‐coated plates in the presence or absence of α‐difluoromethylornithine (DFMO) to inhibit polyamine synthesis. Their attachment over time was observed microscopically, and cell lysates were analyzed by Western blot analysis. We observed that (a) polyamine depletion quantitatively decreased the attachment of cells (b) control cells began to spread within 2 h, while spreading was delayed in polyamine‐depleted cells (c) focal adhesion kinase (FAK) as well as cSrc autophosphorylation was greatly reduced in polyamine‐depleted cells leading to a decrease in Rac‐1 activity during attachment and spreading (d) the Tiam1 inhibitor, NSC‐23766 inhibited Rac‐1 activity. We conclude that polyamines regulate the integrin/Src/FAK complex formation leading to activation of Rac‐1 GEFs. (Supported by NIDDK grant DK‐052784)