Block of TRPC5 channels by 2-aminoethoxydiphenyl borate: a differential, extracellular and voltage-dependent effect
Block of TRPC5 channels by 2-aminoethoxydiphenyl borate: a differential, extracellular and voltage-dependent effect
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DOI：
10.1038/sj.bjp.0706197
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发表时间：
2005-06-01
影响因子：
7.3
通讯作者：
Beech, DJ
中科院分区：
文献类型：
--
作者：
Xu, SZ;Zeng, FN;Beech, DJ
1 2-氨基乙氧基二苯基硼酸酯（2-APB）已被广泛用于研究肌醇1，4，5-三磷酸盐受体（IP（3）Rs）和钙库操纵的Ca 2+内流，并且是瞬时受体电位（TRP）基因编码的阳离子通道的新兴调节剂。2使用Ca 2+指示剂染料和膜片钳记录，我们首先检查了2-三磷酸盐受体（IP（3）Rs）和钙库操纵的Ca 2+内流的阻断作用。APB对HEK-293细胞中表达的人TRPC 5通道的作用。3浓度-反应曲线的IC 50为20 μ M，斜率接近1.0，表明每个通道结合一个2-APB分子。其他钙通道阻滞剂（包括甲氧基维拉帕米、硝苯地平、N-炔丙基尼群地平或小檗碱）不具有这种阻滞作用。4在全细胞和离体膜斑片记录中，2-APB作用于细胞外膜面，而非细胞内膜面。5 2-APB对TRPC 5的阻滞在正电压下较少，表明它进入电场或通过调节通道门控作用。6 2-APB还阻断HEK-293细胞中表达的TRPC 6和TRPM 3，而不是TRPM 2.7 2-APB阻断TRP通道可能与细胞增殖有关，因为2-APB阻断TRP通道可能与细胞增殖有关。APB对过表达TRPC 5的细胞增殖具有更大的抑制作用。8我们的数据表明TRPC 5上的一个特异性和功能重要的结合位点，通过2-APB启用阻塞。该位点仅可通过细胞外途径获得，并且阻断显示出轻度电压依赖性。
1 2-Aminoethoxydiphenyl borate (2-APB) has been widely used to examine the roles of inositol 1,4,5-trisphosphate receptors (IP(3)Rs) and store-operated Ca2+ entry and is an emerging modulator of cationic channels encoded by transient receptor potential (TRP) genes.2 Using Ca2+-indicator dye and patch-clamp recording we first examined the blocking effect of 2-APB on human TRPC5 channels expressed in HEK-293 cells.3 The concentration-response curve has an IC50 of 20 mu M and slope close to 1.0, suggesting one 2-APB molecule binds per channel. The blocking effect is not shared by other Ca2+ channel blockers including methoxyverapamil, nifedipine, N-propargylnitrendipine, or berberine.4 In whole-cell and excised membrane patch recordings, 2-APB acts from the extracellular but not intracellular face of the membrane.5 Block of TRPC5 by 2-APB is less at positive voltages, suggesting that it enters the electric field or acts by modulating channel gating.6 2-APB also blocks TRPC6 and TRPM3 expressed in HEK-293 cells, but not TRPM2.7 Block of TRP channels by 2-APB may be relevant to cell proliferation because 2-APB has a greater inhibitory effect on proliferation in cells overexpressing TRPC5.8 Our data indicate a specific and functionally important binding site on TRPC5 that enables block by 2-APB. The site is only available via an extracellular route and the block shows mild voltage-dependence.