Activation of cellular signalling pathways by hypotonicity

One of the earliest events in the cellular response to an increase in cell volume is the activation of K+ and Cl- selective ionic conductances. Using the epithelial Intestine 407 cell line as a model, we investigated signal transduction cascades activated by hypo-osmotic cell swelling as well as their potential role in ionic channel regulation. The results from these studies imply not only an essential role for protein tyrosine phosphorylation in the regulation of osmo-sensitive anion channels but also indicate the involvement of the small GTP binding protein p21-Rho.