Dwarf open reading frame (DWORF) is a direct activator of the sarcoplasmic reticulum calcium pump SERCA.
Dwarf open reading frame (DWORF) is a direct activator of the sarcoplasmic reticulum calcium pump SERCA.
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DOI：
10.7554/elife.65545
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发表时间：
2021-06-02
期刊：
影响因子：
7.7
通讯作者：
Young HS
中科院分区：
文献类型：
--
作者：
Fisher ME;Bovo E;Aguayo-Ortiz R;Cho EE;Pribadi MP;Dalton MP;Rathod N;Lemieux MJ;Espinoza-Fonseca LM;Robia SL;Zima AV;Young HS
肌浆网钙泵（SERCA）在肌肉的收缩-松弛循环中起着至关重要的作用。在心肌中，SERCA受抑制剂磷蛋白的调控。据报道，一种新的调控因子，侏儒开放阅读框（DWORF）取代了SERCA中的磷蛋白。在这里，我们发现DWORF是SERCA的直接激活剂，在没有磷蛋白的情况下增加其周转率。细胞内钙动力学的测量支持了这一观察结果，并证明DWORF增加了serca依赖性钙的再摄取。这些功能观察揭示了DWORF激活和磷蛋白抑制SERCA的相反作用。为了深入了解SERCA活化的机制，荧光共振能量转移实验显示，在钙存在下，DWORF对SERCA具有更高的亲和力。分子模型和分子动力学模拟提供了DWORF激活SERCA的模型，其中DWORF调节膜双分子层并稳定在细胞质钙升高期间占主导地位的SERCA构象。
The sarco-plasmic reticulum calcium pump (SERCA) plays a critical role in the contraction-relaxation cycle of muscle. In cardiac muscle, SERCA is regulated by the inhibitor phospholamban. A new regulator, dwarf open reading frame (DWORF), has been reported to displace phospholamban from SERCA. Here, we show that DWORF is a direct activator of SERCA, increasing its turnover rate in the absence of phospholamban. Measurement of in-cell calcium dynamics supports this observation and demonstrates that DWORF increases SERCA-dependent calcium reuptake. These functional observations reveal opposing effects of DWORF activation and phospholamban inhibition of SERCA. To gain mechanistic insight into SERCA activation, fluorescence resonance energy transfer experiments revealed that DWORF has a higher affinity for SERCA in the presence of calcium. Molecular modeling and molecular dynamics simulations provide a model for DWORF activation of SERCA, where DWORF modulates the membrane bilayer and stabilizes the conformations of SERCA that predominate during elevated cytosolic calcium.