Dimer/monomer status and in vivo function of salt-bridge mutants of the plant UV-B photoreceptor UVR8.
Dimer/monomer status and in vivo function of salt-bridge mutants of the plant UV-B photoreceptor UVR8.
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DOI：
10.1111/tpj.13260
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发表时间：
2016-10
期刊：
影响因子：
--
通讯作者：
Jenkins GI
中科院分区：
文献类型：
--
作者：
Heilmann M;Velanis CN;Cloix C;Smith BO;Christie JM;Jenkins GI
抗紫外线LORISTANCE 8（UVR 8）是一种紫外-B（UV-B）光的感光体，可引发植物的光形态发生反应。UV-B光感受导致二聚体UVR 8快速解离成单体，单体与结构性光形态发生1（COP 1）相互作用以启动信号转导。用纯化的UVR 8进行的实验表明，二聚体是通过二聚体界面上特定带电氨基酸之间的盐桥相互作用来维持的。然而，很少有人知道这些带电的氨基酸在决定二聚体/单体状态和UVR 8功能在植物中的重要性。在这里，我们评估了使用不同的方法来检查UVR 8的二聚体/单体状态，并表明几个盐桥氨基酸的突变影响二聚体/单体状态，与COP 1的相互作用以及体内UVR 8的感光功能。特别地，精氨酸286与精氨酸96和精氨酸107之间形成的盐桥是二聚体形成的关键。精氨酸286突变为丙氨酸会损害二聚体的形成、与COP 1的相互作用和体内功能，而突变为赖氨酸会产生体内功能减弱的二聚体，表明精氨酸/赖氨酸残基的正电荷对二聚体形成的重要性。值得注意的是，UVR 8突变体（其中第96和107位氨基酸保守突变为天冬酰胺）在二聚体形成方面受到严重损害，但在体内介导UV-B反应，具有与野生型相似的剂量-反应关系。该突变体的UV-B响应性与二聚体形成和单体化无关，表明单体UVR 8具有UV-B光感受的潜力，启动植物中的信号转导和响应。植物光感受器UVR 8介导对UV-B的光形态发生反应。当同源二聚体UVR 8蛋白吸收UV-B时，维持二聚体结构的带电氨基酸之间的相互作用被中和，导致单体化并启动信号转导。在这里，我们确定了特定的带电氨基酸在促进二聚体形成和光感受器功能中的重要性，但表明在二聚化中严重受损的特定突变蛋白仍然能够介导体内对UV-B的反应，表明单体UVR 8在光感受中可以是活跃的。
UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor for ultraviolet‐B (UV‐B) light that initiates photomorphogenic responses in plants. UV‐B photoreception causes rapid dissociation of dimeric UVR8 into monomers that interact with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) to initiate signal transduction. Experiments with purified UVR8 show that the dimer is maintained by salt‐bridge interactions between specific charged amino acids across the dimer interface. However, little is known about the importance of these charged amino acids in determining dimer/monomer status and UVR8 function in plants. Here we evaluate the use of different methods to examine dimer/monomer status of UVR8 and show that mutations of several salt‐bridge amino acids affect dimer/monomer status, interaction with COP1 and photoreceptor function of UVR8 in vivo. In particular, the salt‐bridges formed between arginine 286 and aspartates 96 and 107 are key to dimer formation. Mutation of arginine 286 to alanine impairs dimer formation, interaction with COP1 and function in vivo, whereas mutation to lysine gives a weakened dimer that is functional in vivo, indicating the importance of the positive charge of the arginine/lysine residue for dimer formation. Notably, a UVR8 mutant in which aspartates 96 and 107 are conservatively mutated to asparagine is strongly impaired in dimer formation but mediates UV‐B responses in vivo with a similar dose–response relationship to wild‐type. The UV‐B responsiveness of this mutant does not correlate with dimer formation and monomerisation, indicating that monomeric UVR8 has the potential for UV‐B photoreception, initiating signal transduction and responses in plants. The plant photoreceptor UVR8 mediates photomorphogenic responses to UV‐B. When the homo‐dimeric UVR8 protein absorbs UV‐B, interactions between charged amino acids that maintain the dimer structure are neutralized, causing monomerisation and initiating signal transduction. Here we determine the importance of specific charged amino acids in promoting dimer formation and photoreceptor function, but show that particular mutant proteins strongly impaired in dimerisation are still capable of mediating responses to UV‐B in vivo, indicating that monomeric UVR8 can be active in photoreception.
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DOI：
10.1111/pce.12724
发表时间：
2016-08
期刊：
Plant, cell & environment
影响因子：
--
作者：
Findlay KM;Jenkins GI
通讯作者：
Jenkins GI
影响因子：
7.4
作者：
Heilmann, Monika;Jenkins, Gareth I.
通讯作者：
Jenkins, Gareth I.
DOI：
10.1199/tab.0164
发表时间：
2013-01-01
期刊：
The arabidopsis book
影响因子：
--
作者：
Tilbrook, Kimberley;Arongaus, Adriana B;Ulm, Roman
通讯作者：
Ulm, Roman
DOI：
10.1073/pnas.0308044100
发表时间：
2004-02-03
影响因子：
11.1
作者：
Ulm, R;Baumann, A;Nagy, F
通讯作者：
Nagy, F
DOI：
10.1126/science.1218091
发表时间：
2012-03-23
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Christie JM;Arvai AS;Baxter KJ;Heilmann M;Pratt AJ;O'Hara A;Kelly SM;Hothorn M;Smith BO;Hitomi K;Jenkins GI;Getzoff ED
通讯作者：
Getzoff ED