Arabidopsis CDPK6 phosphorylates ADF1 at N-terminal serine 6 predominantly
Arabidopsis CDPK6 phosphorylates ADF1 at N-terminal serine 6 predominantly
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DOI：
10.1007/s00299-013-1482-6
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发表时间：
2013-11-01
影响因子：
6.2
通讯作者：
Hong, Yan
中科院分区：
文献类型：
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作者：
Dong, Chun-Hai;Hong, Yan
我们发现，拟南芥AtADF1在丝氨酸6位主要被AtCDPK6磷酸化，并且磷酸化调节在ADF1介导的肌动蛋白细丝解聚的调节中起关键作用。由于肌动蛋白解聚因子(ADF)在真核生物中高度保守，它是肌动蛋白组织的关键调节器之一。在植物中，ADF直接参与肌动蛋白细丝的解聚，因此对F-肌动蛋白依赖的细胞活动很重要。ADF的活性通过一系列分子机制受到严格控制，包括磷酸化介导的ADF失活。为了研究拟南芥ADF1的磷酸化调控，我们构建了AtADF1磷酸化位点特异性突变体。利用瞬时表达和稳定转基因方法，我们分析了ADF1磷酸化突变体在植物细胞肌动蛋白细丝组织调控中的作用。体外磷酸化实验表明，AtCDPK6主要在丝氨酸6处对AtADF1进行磷酸化。化学诱导AtCDPK6的表达可以负调控野生型AtADF1解聚肌动蛋白细丝，但不能调节突变体AtADF1(S6A)和AtADF1(S6D)的表达。这些结果表明，拟南芥CDPK6在AtADF1的N端磷酸化中具有调节功能。
We found that Arabidopsis AtADF1 was phosphorylated by AtCDPK6 at serine 6 predominantly and the phosphoregulation plays a key role in the regulation of ADF1-mediated depolymerization of actin filaments.Since actin-depolymerizing factor (ADF) is highly conserved among eukaryotes, it is one of the key modulators for actin organization. In plants, ADF is directly involved in the depolymerization of actin filaments, and therefore important for F-actin-dependent cellular activities. The activity of ADF is tightly controlled through a number of molecular mechanisms, including phosphorylation-mediated inactivation of ADF. To investigate Arabidopsis ADF1 phosphoregulation, we generated AtADF1 phosphorylation site-specific mutants. Using transient expression and stable transgenic approaches, we analyzed the ADF1 phosphorylation mutants in the regulation of actin filament organizations in plant cells. By in vitro phosphorylation assay, we showed that AtADF1 is phosphorylated by AtCDPK6 at serine 6 predominantly. Chemically induced expression of AtCDPK6 can negatively regulate the wild-type AtADF1 in depolymerizing actin filaments, but not those of the mutants AtADF1(S6A) and AtADF1(S6D). These results demonstrate a regulatory function of Arabidopsis CDPK6 in the N-terminal phosphorylation of AtADF1.