Cytosolic domain regulates the calcium sensitivity and surface expression of BEST1 channels in the HEK293 cells |
Kwon Woo Kim1,# (researcher), Junmo Hwang1,# (researcher), Dong-Hyun Kim1 (researcher), Hyungju Park1 (principal researcher), Hyun-Ho Lim 1,2,* (principal researcher) |
1Neurovascular Research Group, Korea Brain Research Institute (KBRI), 2Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST) |
Abstract
BEST family is a class of Ca2+-activated Cl- channels evolutionary well conserved from bacteria to human. The human BEST paralogs (BEST1 – BEST4) share significant amino acid sequence homology in the N-terminal region, which forms the transmembrane helicases and contains the direct calcium-binding site, Ca2+-clasp. But the cytosolic C-terminal region is less conserved in the paralogs. Interestingly, this domain-specific sequence conservation is also found in the BEST1 orthologs. However, the functional role of the C-terminal region in the BEST channels is still poorly understood. Thus, we aimed to understand the functional role of the C-terminal region in the human and mouse BEST1 channels by using electrophysiological recordings. We found that the calcium-dependent activation of BEST1 channels can be modulated by the C-terminal region. The C-terminal deletion hBEST1 reduced the Ca2+-dependent current activation and the hBEST1-mBEST1 chimera showed a significantly reduced calcium sensitivity to hBEST1 in the HEK293 cells. And the C-terminal domain could regulate cellular expression and plasma membrane targeting of BEST1 channels. Our results can provide a basis for understanding the C-terminal roles in the structure-function of BEST family proteins.
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Abstract, Accepted Manuscript(in press) [Submitted on October 24, 2022, Accepted on January 2, 2023] |
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