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1.  Functional and pharmacological characterization of a Shal-related K+ channel subunit in Zebrafish 
BMC Physiology  2008;8:2.
K+ channels are diverse; both in terms of their function and their molecular composition. Shal subunits were first described in Drosophila. There are three mammalian orthologs, which are members of the Kv4 subfamily. They are involved in neuronal firing patterns as well as control of the cardiac action potential duration.
Here, we report the biophysical and pharmacological characterization of zShal3, which is the ortholog of the mammalian Kv4.3 subunit, which in mammals is involved in action potential repolarization and gives rise to neuronal A-type K+ currents involved in somatodendretic signal integration.
We demonstrate that zShal has similar functional and pharmacological characteristics compared to Kv4.3 and it is similarly regulated by pharmacological agents and by the Kv4 accessory subunit, NCS-1.
PMCID: PMC2270284  PMID: 18261223
2.  Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature 
BMC Physiology  2005;5:1.
Electrophysiological data suggest that cardiac KATP channels consist of Kir6.2 and SUR2A subunits, but the distribution of these (and other KATP channel subunits) is poorly defined. We examined the localization of each of the KATP channel subunits in the mouse and rat heart.
Immunohistochemistry of cardiac cryosections demonstrate Kir6.1 protein to be expressed in ventricular myocytes, as well as in the smooth muscle and endothelial cells of coronary resistance vessels. Endothelial capillaries also stained positive for Kir6.1 protein. Kir6.2 protein expression was found predominantly in ventricular myocytes and also in endothelial cells, but not in smooth muscle cells. SUR1 subunits are strongly expressed at the sarcolemmal surface of ventricular myocytes (but not in the coronary vasculature), whereas SUR2 protein was found to be localized predominantly in cardiac myocytes and coronary vessels (mostly in smaller vessels). Immunocytochemistry of isolated ventricular myocytes shows co-localization of Kir6.2 and SUR2 proteins in a striated sarcomeric pattern, suggesting t-tubular expression of these proteins. Both Kir6.1 and SUR1 subunits were found to express strongly at the sarcolemma. The role(s) of these subunits in cardiomyocytes remain to be defined and may require a reassessment of the molecular nature of ventricular KATP channels.
Collectively, our data demonstrate unique cellular and subcellular KATP channel subunit expression patterns in the heart. These results suggest distinct roles for KATP channel subunits in diverse cardiac structures.
PMCID: PMC546210  PMID: 15647111

Results 1-2 (2)