Dr. Barbara Rosati
of ion channel genes underlies differences in the action potential shapes
in cardiac myocytes isolated from different regions of the heart (e.g.
ventricular myocytes versus Purkinje fibers) and is a major contributor
to the functional specialization of the cardiac cells. Nonetheless,
very little is currently known about the regulation of ion channel gene
expression in the adult heart. The KChIP2 gene encodes a calcium-binding
protein, which associates with K+ channels of the Kv4 family modifying
their biophysical properties and facilitating their targeting to the
cell membrane1,2. We have recently proposed that uneven expression of
the KChIP2 gene across the cardiac left ventricle is responsible for
the heterogeneity in the transient outward K+ current (Ito) density3.
A deeper analysis of the KChIP2 gene and Ito expression across the ventricles
shows a very complex pattern4. We are currently investigating the mechanisms
that govern this distribution.