Negatively charged residues adjacent to IFM motif in the DIII-DIV linker of hNa(V)1.4 differentially affect slow inactivation.
Negatively charged residues adjacent to IFM motif in the DIII-DIV linker of hNa(V)1.4 differentially affect slow inactivation.
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hNa(V)1.4 的 DIII-DIV 连接子中与 IFM 基序相邻的带负电荷残基对缓慢失活有不同的影响。
DOI：
10.1016/s0014-5793(03)00912-8
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发表时间：
2003
期刊：
影响因子：
3.5
通讯作者：
Ruben,PeterC
中科院分区：
文献类型：
--
作者：
McCollum,IsabelleJ;Vilin,YuriyY;Spackman,Elizabeth;Fujimoto,Esther;Ruben,PeterC
研究了人骨骼肌电压门控钠通道 (hNaV1.4) 的 DIII-DIV 细胞质接头（假定的快速失活颗粒）中 IFM 基序周围的带负电残基 D1309 和 EE1314,15 对电荷取代、中和和逆转的慢失活 (SI) 的影响。将 1309 位的天冬氨酸 (D) 更改为谷氨酸 (E)（取代）不会强烈影响 SI，而电荷中和为谷氨酰胺 (Q) 和电荷反转为精氨酸 (R) 会使稳态 SI 曲线的中点右移。位置 1309 处的电荷中和 (D→Q) 也降低了与 SI 相关的表观价态。位置 1314 和 1315 处的谷氨酸 (E) 也发生类似突变。电荷反转 (EE→RR) 使稳态 SI 曲线右移，反转和取代 (EE→DD) 均降低了其表观价态。电荷中和（EE→QQ）和反转降低了 SI 的最大概率。这些突变对 SI 的发生率和恢复率也有不同的影响。这些结果表明 DIII-DIV 连接子中的带电残基可能与控制 SI 的结构相互作用。
The effects on slow inactivation (SI) of charge substitutions, neutralizations, and reversals were studied for the negatively charged residues D1309 and EE1314,15 surrounding the IFM motif in the DIII–DIV cytoplasmic linker – the putative fast inactivation particle – of human skeletal muscle voltage-gated sodium channel (hNaV1.4). Changing aspartate (D) at position 1309 to glutamate (E) (substitution) did not strongly affect SI, whereas charge neutralization to glutamine (Q) and charge reversal to arginine (R) right-shifted the midpoint of the steady-state SI curve. Charge neutralization (D→Q) at position 1309 also reduced the apparent valence associated with SI. Glutamates (E) at positions 1314 and 1315 were similarly mutated. Charge reversal (EE→RR) right-shifted the steady-state SI curve and both reversal and substitution (EE→DD) reduced its apparent valence. Charge neutralization (EE→QQ) and reversal decreased the maximum probability of SI. These mutations also had differential effects on the rate of SI onset and recovery. These results suggest that charged residues in the DIII–DIV linker may interact with structures that control SI.