SCAR Mediates Light-Induced Root Elongation in Arabidopsis through Photoreceptors and Proteasomes
SCAR Mediates Light-Induced Root Elongation in Arabidopsis through Photoreceptors and Proteasomes
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DOI：
10.1105/tpc.111.088823
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发表时间：
2011-10-01
期刊：
影响因子：
11.6
通讯作者：
Blancaflor, Elison B.
中科院分区：
文献类型：
--
作者：
Dyachok, Julia;Zhu, Ling;Blancaflor, Elison B.
ARP 2/3复合物是一种高度保守的F-肌动蛋白成核剂，其激活剂SCAR复合物是植物和动物生长所必需的。在这篇文章中，我们提出了一个途径，通过拟南芥根直接感知光，以促进其伸长。ARP 2/3-SCAR复合物和纵向排列的F-肌动蛋白阵列的维持是该途径的关键组成部分。我们发现，SCAR复合体亚基BRK 1/HSPC 300或ARP 2/3-SCAR复合体的其他单个亚基的突变体在光照下表现出对根伸长的显著抑制，这反映了野生型根在黑暗中的生长减少，这支持了ARP 2/3-SCAR复合体参与光调节根生长。组成型光形态发生1（COP 1）E3连接酶和26 S蛋白酶体在黑暗生长的野生型根中的SCAR 1降解伴随着纵向F-肌动蛋白的损失和根生长减少。由根光感受器，隐花色素和光敏色素感知的光抑制COP 1介导的SCAR 1降解。综上所述，我们的数据提供了一个生物化学的解释，光诱导的促进根伸长的ARP 2/3-SCAR复合物。
The ARP2/3 complex, a highly conserved nucleator of F-actin, and its activator, the SCAR complex, are essential for growth in plants and animals. In this article, we present a pathway through which roots of Arabidopsis thaliana directly perceive light to promote their elongation. The ARP2/3-SCAR complex and the maintenance of longitudinally aligned F-actin arrays are crucial components of this pathway. The involvement of the ARP2/3-SCAR complex in light-regulated root growth is supported by our finding that mutants of the SCAR complex subunit BRK1/HSPC300, or other individual subunits of the ARP2/3-SCAR complex, showed a dramatic inhibition of root elongation in the light, which mirrored reduced growth of wildtype roots in the dark. SCAR1 degradation in dark-grown wild-type roots by constitutive photomorphogenic 1 (COP1) E3 ligase and 26S proteasome accompanied the loss of longitudinal F-actin and reduced root growth. Light perceived by the root photoreceptors, cryptochrome and phytochrome, suppressed COP1-mediated SCAR1 degradation. Taken together, our data provide a biochemical explanation for light-induced promotion of root elongation by the ARP2/3-SCAR complex.