Activation of the archaeal ion channel MthK is exquisitely regulated by temperature.
Activation of the archaeal ion channel MthK is exquisitely regulated by temperature.
复制标题
DOI：
10.7554/elife.59055
复制
发表时间：
2020-12-04
期刊：
影响因子：
7.7
通讯作者：
Chanda B
中科院分区：
文献类型：
--
作者：
Jiang Y;Idikuda V;Chowdhury S;Chanda B
Physiological response to thermal stimuli in mammals is mediated by a structurally diverse class of ion channels, many of which exhibit polymodal behavior. To probe the diversity of biophysical mechanisms of temperature-sensitivity, we characterized the temperature-dependent activation of MthK, a two transmembrane calcium-activated potassium channel from thermophilic archaebacteria. Our functional complementation studies show that these channels are more efficient at rescuing K+ transport at 37°C than at 24°C. Electrophysiological activity of the purified MthK is extremely sensitive (Q10 >100) to heating particularly at low-calcium concentrations whereas channels lacking the calcium-sensing RCK domain are practically insensitive. By analyzing single-channel activities at limiting calcium concentrations, we find that temperature alters the coupling between the cytoplasmic RCK domains and the pore domain. These findings reveal a hitherto unexplored mechanism of temperature-dependent regulation of ion channel gating and shed light on ancient origins of temperature-sensitivity.
