Light-Response Bric-A-Brack/Tramtrack/Broad proteins mediate cryptochrome 2 degradation in response to low ambient temperature
Light-Response Bric-A-Brack/Tramtrack/Broad proteins mediate cryptochrome 2 degradation in response to low ambient temperature
复制标题
光响应 Bric-A-Brack/Tramtrack/Broad 蛋白可响应低环境温度介导隐花色素 2 降解。
DOI：
10.1093/plcell/koab219
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发表时间：
2021-08-31
期刊：
影响因子：
11.6
通讯作者：
Liu, Hongtao
中科院分区：
文献类型：
--
作者：
Ma, Libang;Li, Xu;Liu, Hongtao
隐花色素（crys）是一种类似于光裂合酶的蓝光受体，首先在拟南芥中发现，后来在所有主要的进化谱系中得到了鉴定。Crys不仅参与蓝光反应，还参与温度反应;然而，cry蛋白的稳定性是否以及如何受温度调节仍然未知。在这里，我们表明，cry 2蛋白的丰度是由环境温度和cry 2蛋白在低环境温度下通过26 S蛋白酶体降解调制。与此一致，cry 2在低环境温度下显示出高水平的泛素化。有趣的是，cry 2在低环境温度下的降解仅发生在蓝光下，而不是在红光或黑暗条件下，表明cry 2在低环境温度下的蓝光依赖性降解。此外，低环境温度促进光响应Bric-a-Brack/Tramtrack/Broad（LRB）蛋白与cry 2的物理相互作用，以调节其响应于环境温度的泛素化和蛋白质稳定性。LRB通过调节cry 2蛋白的蛋白质稳定性促进高温诱导的下胚轴伸长。这些结果表明cry 2的积累不仅受蓝光的调节，而且受环境温度的调节，并且LRB是cry 2在低环境温度下降解的原因。高温对cry 2的稳定作用使得cry 2成为温度响应的更好的负调节剂。
Cryptochromes (crys) are photolyase-like blue-light receptors first discovered in Arabidopsis thaliana and later identified in all major evolutionary lineages. Crys are involved in not only blue light responses but also in temperature responses; however, whether and how cry protein stability is regulated by temperature remains unknown. Here, we show that cry2 protein abundance is modulated by ambient temperature and cry2 protein is degraded under low ambient temperature via the 26S proteasome. Consistent with this, cry2 shows high levels of ubiquitination under low ambient temperatures. Interestingly, cry2 degradation at low ambient temperatures occurs only under blue light and not under red light or dark conditions, indicating blue-light-dependent degradation of cry2 at low ambient temperature. Furthermore, low ambient temperature promotes physical interaction of Light-Response Bric-a-Brack/Tramtrack/Broad (LRB) proteins with cry2 to modulate its ubiquitination and protein stability in response to ambient temperature. LRBs promote high-temperature-induced hypocotyl elongation by modulating the protein stability of cry2 protein. These results indicate that cry2 accumulation is regulated by not only blue light but also ambient temperature, and LRBs are responsible for cry2 degradation at low ambient temperature. The stabilization of cry2 by high temperature makes cry2 a better negative regulator of temperature responses.