Calcium homeostasis modulator 2 (Calhm2) as slowly activating membrane current channel in mouse B cells
Si Won Choi1, Jae-Won Kwon2, Tong Mook Kang3
1Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea; Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Republic of Korea.
Abstract:
In mouse B lymphocytes, an unidentified slow-activating voltage-dependent current resembling the characteristics of the Calhm family ion channel (ICalhm-L) was investigated. RT-PCR analysis revealed the presence of Calhm2 and 6 transcripts, with subsequent whole-cell patch-clamp studies indicating that the ICalhm-L is augmented by heat, alkaline pH, and low extracellular [Ca2+]. Overexpression of Calhm2, but not Calhm6, in N2A cells recapitulated ICalhm-L. Moreover, Calhm2 knockdown in Bal-17 cells abolished ICalhm-L. We firstly identify the voltage-dependent ion channel function of the Calhm2 in the mouse immune cells. ATP release assays in primary mouse B cells suggested a significant contribution of Calhm2 for purinergic signaling at physiological temperature.
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