An IQ domain mediates the interaction with calmodulin in a plant cyclic nucleotide-gated channel.
An IQ domain mediates the interaction with calmodulin in a plant cyclic nucleotide-gated channel.
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DOI：
10.1093/pcp/pct021
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发表时间：
2013-04
影响因子：
4.9
通讯作者：
Dietrich P
中科院分区：
文献类型：
--
作者：
Fischer C;Kugler A;Hoth S;Dietrich P
环核苷酸门控通道(CNGC)是由钙调素(CaM)调节的非选择性阳离子进入途径，CaM是真核生物中普遍存在的钙离子感受器。尽管CaM结合被证明对依赖于钙离子的CNGC活性的反馈调节很重要，但这些通道的CaM结合特性仅在少数情况下被研究过。我们发现来自拟南芥的CNGC20以钙离子依赖的方式与CaM结合，并与所有AtCaM亚型相互作用，但不与CaM样蛋白CML8和CML9相互作用。在PLANTA中，用双分子荧光互补的方法证明了CaM与全长通道的相互作用。这种相互作用发生在质膜上，与我们的绿色荧光蛋白(GFP)融合的CNGC20蛋白的定位数据一致。CaM结合位点被定位于异亮氨酸谷氨酰胺(IQ)基序，这一基序在植物CNGCs中尚未被鉴定。我们的结果表明，与目前研究的CNGCs中环核苷酸和CaM的重叠结合部位相比，它们在CNGC20中是按顺序排列的。两种可供选择的CaM结合模式的存在表明，植物CNGCs的配体调控比之前预期的要复杂得多。由于IQ结构域在植物CNGC中是保守的，该结构域增加了依赖钙离子的通道控制机制的可变性，突显了这个多基因家族的功能多样性。
Cyclic nucleotide-gated channels (CNGCs) form non-selective cation entry pathways regulated by calmodulin (CaM), a universal Ca2+ sensor in eukaryotes. Although CaM binding has been shown to be important for Ca2+-dependent feedback regulation of CNGC activity, the CaM-binding properties of these channels have been investigated in a few cases only. We show that CNGC20 from Arabidopsis thaliana binds CaM in a Ca2+-dependent manner and interacts with all AtCaM isoforms but not with the CaM-like proteins CML8 and CML9. CaM interaction with the full-length channel was demonstrated in planta, using bimolecular fluorescence complementation. This interaction occurred at the plasma membrane, in accordance with our localization data of green fluorescent protein (GFP)-fused CNGC20 proteins. The CaM-binding site was mapped to an isoleucine glutamine (IQ) motif, which has not been characterized in plant CNGCs so far. Our results show that compared with the overlapping binding sites for cyclic nucleotides and CaM in CNGCs studied so far, they are sequentially organized in CNGC20. The presence of two alternative CaM-binding modes indicates that ligand regulation of plant CNGCs is more complex than previously expected. Since the IQ domain is conserved among plant CNGCs, this domain adds to the variability of Ca2+-dependent channel control mechanisms underlining the functional diversity within this multigene family.
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DOI：
10.1085/jgp.200709786
发表时间：
2007-05
期刊：
The Journal of general physiology
影响因子：
--
作者：
Dunlap K
通讯作者：
Dunlap K
影响因子：
5.8
作者：
Gautier, Romain;Douguet, Dominique;Drin, Guillaume
通讯作者：
Drin, Guillaume
影响因子：
6.9
作者：
Kanter U;Hauser A;Michalke B;Dräxl S;Schäffner AR
通讯作者：
Schäffner AR
影响因子：
1.1
作者：
Chin, Kimberley;Moeder, Wolfgang;Yoshioka, Keiko
通讯作者：
Yoshioka, Keiko
影响因子：
27.5
作者：
Gehl, Christian;Waadt, Rainer;Haensch, Robert
通讯作者：
Haensch, Robert