CLC anion/proton exchangers control the pH and [Cl⁻] of the endolysosomal system that is essential for cellular nutrient uptake. Here, we use heterologous expression and whole‐cell electrophysiology to investigate the regulation of the CLC isoforms ClC‐3, ClC‐4, and ClC‐5 by the adenylic system components ATP , ADP , and AMP . Our results show that cytosolic ATP and ADP but not AMP and Mg²⁺‐free ADP enhance CLC ion transport. Biophysical analysis reveals that adenine nucleotides alter the ratio between CLC ion transport and CLC gating charge and shift the CLC voltage‐dependent activation. The latter effect is suppressed by blocking the intracellular entrance of the proton transport pathway. We suggest, therefore, that adenine nucleotides regulate the internal proton delivery into the CLC transporter machinery and alter the probability of CLC transporters to undergo silent non‐transporting cycles. Our findings suggest that the CBS domains in mammalian CLC transporters serve as energy sensors that regulate vesicular Cl⁻/H⁺ exchange by detecting changes in the cytosolic ATP /ADP /AMP equilibrium. Such sensing mechanism links the endolysosomal activity to the cellular metabolic state.

中文翻译：

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哺乳动物 CLC 阴离子/质子交换器的代谢能量传感。


CLC 阴离子/质子交换器控制内溶酶体系统的 pH 和 [Cl ^- ]，这对于细胞营养吸收至关重要。在这里，我们使用异源表达和全细胞电生理学来研究腺苷酸系统成分 ATP 、 ADP 和 AMP 对 CLC 异构体​​ ClC-3、ClC-4 和 ClC-5 的调节。我们的结果表明，胞质 ATP 和 ADP，而非 AMP 和不含 Mg ²⁺的 ADP 增强了 CLC 离子转运。生物物理分析表明，腺嘌呤核苷酸改变了 CLC 离子传输和 CLC 门控电荷之间的比率，并改变了 CLC 电压依赖性激活。通过阻断质子传输途径的细胞内入口来抑制后一种效应。因此，我们建议腺嘌呤核苷酸调节内部质子递送到 CLC 转运蛋白机器中，并改变 CLC 转运蛋白经历沉默非转运循环的概率。我们的研究结果表明，哺乳动物 CLC 转运蛋白中的 CBS 结构域充当能量传感器，通过检测胞质 ATP /ADP /AMP 平衡的变化来调节囊泡 Cl ^- /H ⁺交换。这种传感机制将内溶酶体活性与细胞代谢状态联系起来。