Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.
Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.
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DOI：
10.1186/1472-6793-5-1
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发表时间：
2005-01-12
期刊：
影响因子：
--
通讯作者：
Coetzee, William A
中科院分区：
文献类型：
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作者：
Morrissey, Alison;Rosner, Erika;Coetzee, William A
背景：电生理数据表明，心脏KATP通道由Kir6.2和SUR2A亚基组成，但这些亚基（以及其他KATP通道亚基）的分布尚未明确。我们检测了小鼠和大鼠心脏中每个KATP通道亚基的定位。结果：心脏冷冻切片免疫组化显示Kir6.1蛋白在心室肌细胞、平滑肌和冠状动脉阻力血管内皮细胞中表达。内皮毛细血管也呈Kir6.1蛋白阳性。Kir6.2蛋白主要在心室肌细胞和内皮细胞中表达，而在平滑肌细胞中不表达。SUR1亚基在心室肌细胞的肌层表面强烈表达（但在冠状血管中不表达），而SUR2蛋白主要定位于心肌细胞和冠状血管（主要在较小的血管中）。分离心室肌细胞的免疫细胞化学显示Kir6.2和SUR2蛋白在横纹肌细胞模式中共定位，提示这些蛋白在t管中表达。Kir6.1和SUR1亚基均在肌膜处强烈表达。这些亚基在心肌细胞中的作用仍有待确定，可能需要重新评估心室KATP通道的分子性质。结论：总的来说，我们的数据证明了心脏中独特的细胞和亚细胞KATP通道亚基表达模式。这些结果表明KATP通道亚基在不同心脏结构中的不同作用。
BACKGROUND: 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.RESULTS: 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.CONCLUSIONS: 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.