A study of the blue-light-dependent phosphorylation, degradation, and photobody formation of Arabidopsis CRY2.
A study of the blue-light-dependent phosphorylation, degradation, and photobody formation of Arabidopsis CRY2.
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拟南芥 CRY2 蓝光依赖性磷酸化、降解和光体形成的研究。
DOI：
10.1093/mp/sss007
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发表时间：
2012-05
期刊：
影响因子：
27.5
通讯作者：
Lin, Chentao
中科院分区：
文献类型：
--
作者：
Feng, Deshun;Sun, Shihfan;Liu, Bin (通讯作者);Lin, Chentao
拟南芥隐花色素2（Arabidopsis cryptochrome 2，BCR 2）是一种蓝光受体，它介导蓝光抑制下胚轴的伸长和光周期促进花的起始。CD 402是一种组成性核蛋白，在细胞核中经历蓝光依赖性磷酸化、泛素化、光体形成和降解，但这些蓝光依赖性事件之间的关系仍不清楚。已经提出，β 2磷酸化触发负责随后的泛素化和光体形成的构象变化，导致β 2功能和/或降解。我们测试了这一假设的结构-功能的研究，使用突变体的GFP融合蛋白在转基因拟南芥中表达。我们发现，赖氨酸残基的NLS（核定位信号）序列的精氨酸残基的变化，部分损害核输入的NLS 2K 541 R和NLS 2K 554/5 R突变蛋白，导致减少磷酸化，生理活性，并响应于蓝光降解。与只在细胞核中形成光体的野生型p53 2蛋白相反，p53 2K 541 R和p53 2K 554/5 R突变蛋白在细胞核和细胞质中响应蓝光形成蛋白体。这些结果表明，光激发的α 2分子可以聚集形成光体样结构，而不需要核依赖的蛋白质修饰或与核α 2相互作用蛋白的缔合。综上所述，观察到在蓝光作用下，光激发的隐花色素形成光体的速度明显快于光激发的磷酸化，我们推测，光激发的隐花色素形成低聚物，先于光激发的其他生化变化，以促进光体的形成、信号放大和传播，以及降解的脱敏作用。
Arabidopsis cryptochrome 2 (CRY2) is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS (Nuclear Localization Signal) sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2K541R and CRY2K554/5R mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/5R mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.
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影响因子：
9.5
作者：
Liu B;Liu H;Zhong D;Lin C
通讯作者：
Lin C
影响因子：
6.7
作者：
Wang YE;Park A;Lake M;Pentecost M;Torres B;Yun TE;Wolf MC;Holbrook MR;Freiberg AN;Lee B
通讯作者：
Lee B
DOI：
10.1073/pnas.95.5.2686
发表时间：
1998-03-03
影响因子：
11.1
作者：
Lin, CT;Yang, HY;Cashmore, AR
通讯作者：
Cashmore, AR
DOI：
10.1073/pnas.1004529107
发表时间：
2010-07-27
影响因子：
11.1
作者：
Jeong, Rae-Dong;Chandra-Shekara, A. C.;Kachroo, Pradeep
通讯作者：
Kachroo, Pradeep
影响因子：
20.5
作者：
Liu, Hongtao;Liu, Bin;Zhao, Chenxi;Pepper, Michael;Lin, Chentao
通讯作者：
Lin, Chentao