Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland.
Structural Biology Group, Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
Int J Mol Sci. 2020 Jul 15;21(14):4984. doi: 10.3390/ijms21144984.
Phosphatidic acid (PA) is involved in the regulation of plant growth and development, as well as responses to various environmental stimuli. Several PA targets in plant cells were identified, including two SNF1-related protein kinases 2 (SnRK2s), SnRK2.10 and SnRK2.4, which are not activated by abscisic acid (ABA). Here, we investigated the effects of PA on various elements of ABA-non-activated SnRK2 signaling. PA 16:0/18:1 was found to modulate the SnRK2 structure and the phosphorylation of some SnRK2 targets. Conversely, phosphorylation by the ABA-non-activated SnRK2s, of one of such targets, dehydrin Early Responsive to Dehydration 14 (ERD14), affects its interaction with PA and subcellular localization. Moreover, PA 16:0/18:1 modulates the activity and/or localization of negative regulators of the ABA-non-activated SnRK2s, not only of the ABA insensitive 1 (ABI1) phosphatase, which was identified earlier, but also of another protein phosphatase 2C, PP2CA. The activity of both phosphatases was inhibited by about 50% in the presence of 50 μM PA. PA 16:0/18:1 also impacts the phosphorylation and subcellular localization of SnRK2-interacting calcium sensor, known to inhibit SnRK2 activity in a calcium-dependent manner. Thus, PA was found to regulate ABA-non-activated SnRK2 signaling at several levels: the activity, phosphorylation status and/or localization of SnRK2 cellular partners.
磷脂酸（PA）参与植物生长发育的调节以及对各种环境刺激的反应。在植物细胞中鉴定出几种 PA 靶标，包括两种 SNF1 相关蛋白激酶 2（SnRK2s），SnRK2.10 和 SnRK2.4，它们不受脱落酸（ABA）的激活。在这里，我们研究了 PA 对各种非 ABA 激活的 SnRK2 信号元素的影响。发现 PA 16:0/18:1 调节 SnRK2 结构和某些 SnRK2 靶标的磷酸化。相反，由非 ABA 激活的 SnRK2s 磷酸化其中一个靶标脱水素早期响应脱水 14（ERD14），影响其与 PA 的相互作用和亚细胞定位。此外，PA 16:0/18:1 调节非 ABA 激活的 SnRK2s 的负调节剂的活性和/或定位，不仅是早期鉴定的 ABA 不敏感 1（ABI1）磷酸酶，而且是另一种蛋白磷酸酶 2C，PP2CA。在存在 50 μM PA 的情况下，两种磷酸酶的活性均被抑制约 50%。PA 16:0/18:1 还影响 SnRK2 相互作用钙传感器的磷酸化和亚细胞定位，已知该传感器以钙依赖的方式抑制 SnRK2 活性。因此，PA 被发现调节非 ABA 激活的 SnRK2 信号在几个水平上：SnRK2 细胞伴侣的活性、磷酸化状态和/或定位。
