title: Two-pore Domain Potassium Channels in Astrocytes.
abstract: Two-pore domain potassium (K2P) channels have a distinct structure and channel properties, and are involved in a background K+current. The 15 members of the K2Pchannels are identified and classified into six subfamilies on the basis of their sequence similarities. The activity of the channels is dynamically regulated by various physical, chemical, and biological effectors. The channels are expressed in a wide variety of tissues in mammals in an isoform specific manner, and play various roles in many physiological and pathophysiological conditions. To function as channels, the K2Pchannels form dimers, and some isoforms form heterodimers that provide diversity in channel properties. In the brain, TWIK1, TREK1, TREK2, TRAAK, TASK1, and TASK3 are predominantly expressed in various regions, including the cerebral cortex, dentate gyrus, CA1-CA3, and granular layer of the cerebellum. TWIK1, TREK1, and TASK1 are highly expressed in astrocytes, where they play specific cellular roles. Astrocytes keep leak K+conductance, called the passive conductance, which mainly involves TWIK1-TREK1 heterodimeric channel. TWIK1 and TREK1 also mediate glutamate release from astrocytes in an exocytosis-independent manner. The expression of TREK1 and TREK2 in astrocytes increases under ischemic conditions, that enhance neuroprotection from ischemia. Accumulated evidence has indicated that astrocytes, together with neurons, are involved in brain function, with the K2Pchannels playing critical role in these astrocytes.
authors: School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02841, Korea.
authors: Kanghyun
authors: K
authors: Ryoo
authors: School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02841, Korea.
authors: Jae-Yong
authors: JY
authors: Park
keywords: K2P channel; astrocyte; glutamate release; passive conductance