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25 results on '"Zhang, Guohui"'

4. Coupling between Ca2+ binding and the activation gate opening in BK channels probed by an allosteric activator

Author

Zhang, Guohui, primary, Xu, Xianjin, additional, Jia, ZhiGuang, additional, Geng, Yanyan, additional, Liang, Hongwu, additional, Shi, Jingyi, additional, Marras, Martina, additional, Abella, Carlota, additional, Magleby, Karl L., additional, Silva, Jonathan R., additional, Chen, Jianhan, additional, Zou, Xiaoqin, additional, and Cui, Jianmin, additional

Published
2022
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8. Redox dependent Cd2+inhibition of BK type Ca2+activated K+channels

Author

Zhang, Guohui, Yang, Huanghe, Wang, Yuyin, Liang, Hongwu, Shi, Jingyi, and Cui, Jianmin

Abstract

Large conductance Ca2+-activated K+channels (BK channels) are formed by Slo1 subunits as a homotetramer. Besides Ca2+, other divalent cations, such as Cd2+, also activate BK channels when applied intracellularly by shifting the conductance-voltage (GV) relation to more negative voltages. However, we found that if the inside-out patch containing BK channels was treated with solution containing reducing agents such as DTT subsequent Cd2+application completely inhibited BK currents. The DTT dependent Cd2+inhibition could be reversed by treating the patch with solutions containing H2O2, suggesting that a redox reaction regulates the Cd2+inhibition of BK channels. Similar DTT dependent Cd2+inhibition was also observed in a mutant BK channel, Core-MT, in which the cytosolic domain of the channel is deleted and in the proton activated Slo3 channels, but not observed in the voltage gated Shaker K+channels. A possible mechanism for the DTT dependent Cd2+inhibition is that DTT treatment breaks one or more disulfide bonds between cysteine pairs in the BK channel protein, and the freed thiol groups coordinate with Cd2+to form an ion bridge that blocks the channel or locks the channel at the closed state. However, surprisingly, none of mutations of all cysteine residues in Slo1 affect the DTT dependent Cd2+inhibition. These results are puzzling with an apparent contradiction: on one hand a redox reaction seems to regulate Cd2+inhibition of the channel, but on the other hand no cysteine residue in Slo1 subunit seems to be involved in such inhibition.

Published
2024
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12. CP1 Opens I Ks Channels by Substituting PIP 2

Author

Naffaa, Moawiah M., primary, Xu, Xianjin, additional, Liang, Hongwu, additional, Zhang, Guohui, additional, Zhan Wang, Hong, additional, Goa, Junyuan, additional, Cohen, Ira S., additional, Zou, Xiaoqin, additional, and Cui, Jianmin, additional

Published
2017
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14. Dynamic Ca2+ Sensitivity of BK Channels

Author

Hou, Panpan, primary, Xiao, Feng, additional, Yuchi, Ming, additional, Zhang, Guohui, additional, Wu, Ying, additional, Wang, Wei, additional, Zeng, Wenping, additional, Ding, Mingyue, additional, Wu, Zhengxing, additional, Cui, Jianming, additional, and Ding, Jiuping, additional

Published
2014
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22. Subunit-Specific Effect of the Voltage Sensor Domain on Ca2+Sensitivity of BK Channels

Author

Yang, Huanghe, Zhang, Guohui, Shi, Jingyi, Lee, Urvi S., Delaloye, Kelli, and Cui, Jianmin

Abstract

Large conductance Ca2+- and voltage-activated K+(BK) channels, composed of pore-forming α-subunits and auxiliary β-subunits, play important roles in diverse physiological processes. The differences in BK channel phenotypes are primarily due to the tissue-specific expression of β-subunits (β1–β4) that modulate channel function differently. Yet, the molecular basis of the subunit-specific regulation is not clear. In our study, we demonstrate that perturbation of the voltage sensor in BK channels by mutations selectively disrupts the ability of the β1-subunit—but not that of the β2-subunit—to enhance apparent Ca2+sensitivity. These mutations change the number of equivalent gating charges, the voltage dependence of voltage sensor movements, the open-close equilibrium of the channel, and the allosteric coupling between voltage sensor movements and channel opening to various degrees, indicating that they alter the conformation and movements of the voltage sensor and the activation gate. Similarly, the ability of the β1-subunit to enhance apparent Ca2+sensitivity is diminished to various degrees, correlating quantitatively with the shift of voltage dependence of voltage sensor movements. In contrast, none of these mutations significantly reduces the ability of the β2-subunit to enhance Ca2+sensitivity. These results suggest that the β1-subunit enhances Ca2+sensitivity by altering the conformation and movements of the voltage sensor, whereas the similar function of the β2-subunit is governed by a distinct mechanism.

Published
2008
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