Roles of AGCVIII Kinases in the Hypocotyl Phototropism of Arabidopsis Seedlings
Roles of AGCVIII Kinases in the Hypocotyl Phototropism of Arabidopsis Seedlings
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DOI：
10.1093/pcp/pcy048
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发表时间：
2018-05-01
影响因子：
4.9
通讯作者：
Sakai, Tatsuya
中科院分区：
文献类型：
--
作者：
Haga, Ken;Frank, Lena;Sakai, Tatsuya
通过磷酸化和去磷酸化来调节蛋白质的功能是许多细胞事件中的一个重要机制。趋光性蓝光受体是植物特有的AGCVIII酶，对趋光性反应是必不可少的。D6蛋白激酶(D6PK)家族的成员，代表AGCVIII激酶的一个亚家族，也参与了趋光性反应，这表明可能还有更多的AGCVIII激酶可能潜在地控制着向光性。本研究探讨了拟南芥AGCVIII激酶在下胚轴向光性中的功能作用。我们证明，D6PK家族的激酶不仅是第二个，也是第一个正向光性所必需的。此外，我们发现一个以前未被描述的AGCVIII蛋白，AGC1-12，参与了第一个正向光性和向重力性。AGC1-12磷酸化PIN形成的1(Pin1)胞质环中的丝氨酸残基，并与D6PK共享亚磷酸盐偏好。我们的工作有力地表明，D6PK家族和AGC1-12是下胚轴向光性和向重力性的关键成分，这些激酶主要通过蛋白质磷酸化调节PIN介导的生长素运输来控制向向性反应。
Regulation of protein function by phosphorylation and dephosphorylation is an important mechanism in many cellular events. The phototropin blue-light photoreceptors, plant-specific AGCVIII kinases, are essential for phototropic responses. Members of the D6 PROTEIN KINASE (D6PK) family, representing a subfamily of the AGCVIII kinases, also contribute to phototropic responses, suggesting that possibly further AGCVIII kinases may potentially control phototropism. The present study investigates the functional roles of Arabidopsis (Arabidopsis thaliana) AGCVIII kinases in hypocotyl phototropism. We demonstrate that D6PK family kinases are not only required for the second but also for the first positive phototropism. In addition, we find that a previously uncharacterized AGCVIII protein, AGC1-12, is involved in the first positive phototropism and gravitropism. AGC1-12 phosphorylates serine residues in the cytoplasmic loop of PIN-FORMED 1 (PIN1) and shares phosphosite preferences with D6PK. Our work strongly suggests that the D6PK family and AGC1-12 are critical components for both hypocotyl phototropism and gravitropism, and that these kinases control tropic responses mainly through regulation of PIN-mediated auxin transport by protein phosphorylation.