Issue No. 1

Modulation of ion channel activity is a fundamental mechanism in many tissues. Ion channels, like many other proteins are targets for several intracellular signaling pathways, including protein phosphorylation and dephosphorylation. These processes can modify channel activity and dramatically alter the electrophysiological properties of both excitable and nonexcitable cells^1-5. The amino acid sequences of ion channels suggest that many contain a wide variety of possible phosphorlyation sites. Phosphorylation in general and Tyrosine Phosphorylation (TP) in particular were shown to participate in the control of ion channel activity. Initial evidence showing that ion channels may be regulated by TP came largely from pharmacological studies using soluble inhibitors for Protein Tyrosine Kinases (PTKs) such as Genistein, K252a/b,