Subcellular Localization of the Voltage-gated Potassium Channel, the Kv2.1 and Kv3 subfamily

Abstract

Many ion channel studies have been performed on the plasma membranes ion channels. However, intracellular organelles ion channels have been investigated recently. The number of studies on the intracellular ion channels has increased, and the importance of intracellular ion channels is now being recognized. In addition, there are studies being carried out to identify the function of subcellular localized ion channels. In the present study, the subcellular localization of the voltage-gated potassium (Kv) channel, the Kv2.1 and Kv3 subfamily were investigated. The results revealed that Kv2.1, Kv3.1, Kv3.2, Kv3.3 and Kv3.4 are detected in the nucleus and mitochondria. The alteration in Kv channel expression according to the cell density in A549 cells was also observed. The expression of Kv3.1 and Kv3.4 located in the nucleus was significantly increased in a cell density-dependent manner. Kv2.1 located in the membrane also significantly increased according to cell density. In addition, changes in Kv3.3 channels expression according to differentiation induced by hemin in K562 cells were observed. The expression level of the nuclear Kv3.3 was increased in the early stage of differentiation. These results demonstrate that the Kv2.1 and Kv3 subfamily were localized not only in the plasma membrane, but also in the nucleus and mitochondria. Furthermore, the subcellular location where the channel expressions were altered was different each other. Although the function of subcellular localized Kv channels is not clear, expression changes imply that these subcellular localized Kv channels could be associated with the proliferation and differentiation of cancer cells.