beta subunits influence the biophysical and pharmacological differences between P- and Q-type calcium currents expressed in a mammalian cell line.
beta subunits influence the biophysical and pharmacological differences between P- and Q-type calcium currents expressed in a mammalian cell line.
复制标题
β 亚基影响哺乳动物细胞系中表达的 P 型和 Q 型钙电流之间的生物物理和药理学差异。
DOI：
10.1073/pnas.94.25.14042
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发表时间：
1997
影响因子：
11.1
通讯作者：
Llinás,R
中科院分区：
文献类型：
--
作者：
Moreno,H;Rudy,B;Llinás,R
制备共表达α 1 A、α2δ和不同β钙通道亚基及绿色荧光蛋白的人肾上皮细胞（HEK）。为了将在这些细胞中观察到的钙电流与天然神经元电流进行比较，同时使用电生理学和药理学工具。人肾上皮α 1A转染细胞的全细胞电流记录显示，在80 mM Ba 2+中存在小的失活电流，对钙阻滞剂相对不敏感。α 1 A、βIb和α2δ的共表达产生了在10 mM Ba 2+中检测到的稳健的失活电流，该失活电流可被低浓度的ω-agatoxin IVA（ω-阿加IVA）或合成漏斗网蜘蛛毒素（sFTX）可逆地阻断。α 1 A、β 2 a、α2δ亚基也支持钡电流，它们表现出最慢的失活，并且对ω-阿加IVA和sFTX相对不敏感。β3与上述相同组合的共表达产生的失活电流对低浓度的ω-阿加IVA和sFTX也不敏感。这些数据表明，α 1 A、βIb、α2δ组合最类似于P型通道，因为其失活速率和对ω-阿加IVA和sFTX的高敏感性。更重要的是，通道阻滞剂的特异性受到与α1A亚基相关的β亚基的高度影响。
Human epithelial kidney cells (HEK) were prepared to coexpress α1A, α2δ with different β calcium channel subunits and green fluorescence protein. To compare the calcium currents observed in these cells with the native neuronal currents, electrophysiological and pharmacological tools were used conjointly. Whole-cell current recordings of human epithelial kidney α1A-transfected cells showed small inactivating currents in 80 mM Ba2+that were relatively insensitive to calcium blockers. Coexpression of α1A, βIb, and α2δ produced a robust inactivating current detected in 10 mM Ba2+, reversibly blockable with low concentration of ω-agatoxin IVA (ω-Aga IVA) or synthetic funnel-web spider toxin (sFTX). Barium currents were also supported by α1A, β2a, α2δ subunits, which demonstrated the slowest inactivation and were relatively insensitive to ω-Aga IVA and sFTX. Coexpression of β3 with the same combination as above produced inactivating currents also insensitive to low concentration of ω-Aga IVA and sFTX. These data indicate that the combination α1A, βIb, α2δ best resembles P-type channels given the rate of inactivation and the high sensitivity to ω-Aga IVA and sFTX. More importantly, the specificity of the channel blocker is highly influenced by the β subunit associated with the α1A subunit.