Engineered CaM2 modulates nuclear calcium oscillation and enhances legume root nodule symbiosis.
Engineered CaM2 modulates nuclear calcium oscillation and enhances legume root nodule symbiosis.
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工程CaM2调控核钙振荡，促进豆科根瘤共生。
DOI：
10.1073/pnas.2200099119
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发表时间：
2022-03-29
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
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作者：
细胞内钙离子浓度的波动在多种细胞过程的调节中起着重要作用。在能够与固氮菌和/或丛枝菌根真菌共生的植物中，核局部钙振荡对于传递微生物信号是必不可少的。虽然产生核局部钙振荡所需的离子通道已经被确定，但它们的调节机制尚不清楚。在这里，我们结合蛋白质组学和工程方法来证明钙结合形式的钙调蛋白2(CAM2)与环核苷酸门控通道15(CNGC15s)相关联，关闭通道并提供负反馈来维持振荡机制。我们进一步揭示，工程化的CAM2促进了早期的内生共生，并增强了根瘤的共生，但不能促进丛枝菌根的共生。固氮细菌和运磷丛枝菌根共生体建立的关键生理事件是诱导内共生体所需的核钙振荡。核质钙浓度的这些规律波动是由位于核膜上的离子通道和泵产生的，包括环核苷酸门控通道15(CNGC15)。然而，CNGC15如何在植物中调节以维持钙振荡机制仍不清楚。在这里，我们证明了CNGC15受钙结合形式的钙调蛋白2(holo-cam2)的调节，当钙释放时，它提供负反馈来关闭CNGC15。结合CaM残基的结构和进化分析以及生物信息学分析，我们设计了一个与CNGC15s具有更高亲和力的全息CAM2。在Planta中，工程holo-cam2的表达加速了钙振荡频率，早期内共生信号，并足以随着时间的推移维持增强的根瘤共生，而不是增加的丛枝菌化。综上所述，这些结果表明，holo-cam2是调控CNGC15s活性和下游根瘤共生途径所需的内生信号的一个组成部分。
Oscillations in intracellular calcium concentration play an essential role in the regulation of multiple cellular processes. In plants capable of root endosymbiosis with nitrogen-fixing bacteria and/or arbuscular mycorrhizal fungi, nuclear localized calcium oscillations are essential to transduce the microbial signal. Although the ion channels required to generate the nuclear localized calcium oscillations have been identified, their mechanisms of regulation are unknown. Here, we combined proteomics and engineering approaches to demonstrate that the calcium-bound form of the calmodulin 2 (CaM2) associates with CYCLIC NUCLEOTIDE GATED CHANNEL 15 (CNGC15s), closing the channels and providing the negative feedback to sustain the oscillatory mechanism. We further unraveled that the engineered CaM2 accelerates early endosymbioses and enhanced root nodule symbiosis but not arbuscular mycorrhization. The key physiological event essential to the establishment of nitrogen-fixing bacteria and phosphate-delivering arbuscular mycorrhizal symbioses is the induction of nuclear calcium oscillations that are required for endosymbioses. These regular fluctuations in nucleoplasmic calcium concentrations are generated by ion channels and a pump located at the nuclear envelope, including the CYCLIC NUCLEOTIDE GATED CHANNEL 15 (CNGC15). However, how the CNGC15s are regulated in planta to sustain a calcium oscillatory mechanism remains unknown. Here, we demonstrate that the CNGC15s are regulated by the calcium-bound form of the calmodulin 2 (holo-CaM2), which, upon release of calcium, provides negative feedback to close the CNGC15s. Combining structural and evolutionary analyses of CaM residues with bioinformatic analysis, we engineered a holo-CaM2 with an increased affinity for CNGC15s. In planta, the expression of the engineered holo-CaM2 accelerates the calcium oscillation frequency, early endosymbioses signaling and is sufficient to sustain over time an enhanced root nodule symbiosis but not an increased arbuscular mycorrhization. Together, these results reveal that holo-CaM2 is a component of endosymbiosis signaling required to modulate CNGC15s activity and the downstream root nodule symbiosis pathway.
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DOI：
10.1073/pnas.1107912108
发表时间：
2011-08-23
影响因子：
11.1
作者：
Capoen, Ward;Sun, Jongho;Oldroyd, Giles E. D.
通讯作者：
Oldroyd, Giles E. D.
真核环核苷酸门控通道的结构。
影响因子：
64.8
作者：
Li M;Zhou X;Wang S;Michailidis I;Gong Y;Su D;Li H;Li X;Yang J
通讯作者：
Yang J
影响因子：
4.8
作者：
Sondergaard, Mads T.;Tian, Xixi;Overgaard, Michael T.
通讯作者：
Overgaard, Michael T.
影响因子：
5.6
作者：
Jauregui E;Du L;Gleason C;Poovaiah BW
通讯作者：
Poovaiah BW
影响因子：
4.9
作者：
Fischer C;Kugler A;Hoth S;Dietrich P
通讯作者：
Dietrich P