ABA signaling prevents phosphodegradation of the SR45 splicing factor to alleviate inhibition of early seedling development in Arabidopsis.
ABA signaling prevents phosphodegradation of the SR45 splicing factor to alleviate inhibition of early seedling development in Arabidopsis.
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DOI：
10.1016/j.xplc.2022.100495
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发表时间：
2023-03-13
影响因子：
10.5
通讯作者：
Duque, Paula
中科院分区：
文献类型：
--
作者：
Albuquerque-Martins, Rui;Szakonyi, Dora;Rowe, James;Jones, Alexander M.;Duque, Paula
富含丝氨酸/精氨酸(SR)的蛋白质是一种保守的剪接调节蛋白，在植物逆境反应中发挥重要作用，即由脱落酸(ABA)激素介导的逆境反应。拟南芥类SR蛋白SR45被认为是幼苗发育早期ABA途径的负调控蛋白。如何抵消ABA信号对生长的抑制以维持植物在胁迫条件下的发育仍在很大程度上是未知的。在这里，我们发现SR45的过表达降低了拟南芥在幼苗发育早期对ABA的敏感性。对表达荧光标记SR45的转基因植物的生化和共聚焦显微镜分析表明，暴露于ABA可使该蛋白在多个氨基酸残基上去磷酸化，并导致其积累，这是因为SR45通过减少泛素化和蛋白酶体降解而稳定。利用含磷突变体和拟南芥转基因株系，我们证明了ABA介导的单一SR45残基T264的去磷酸化在拮抗SR45泛素化和降解以促进其作为幼苗ABA敏感性抑制因子的功能上的相关性。我们的结果揭示了一种通过翻译后控制SR45剪接因子来负向自动调节ABA信号并允许植物在胁迫下早期生长的机制。SR45剪接因子的过度表达是ABA胁迫信号通路的负调控因子，降低了植物对植物激素的敏感性。暴露于ABA使SR45去磷酸化，通过减少泛素化和蛋白酶体降解导致蛋白质的稳定。我们的研究揭示了在胁迫条件下缓解ABA介导的早期植物生长抑制的自动调节机制。
Serine/arginine-rich (SR) proteins are conserved splicing regulators that play important roles in plant stress responses, namely those mediated by the abscisic acid (ABA) hormone. The Arabidopsis thaliana SR-like protein SR45 is a described negative regulator of the ABA pathway during early seedling development. How the inhibition of growth by ABA signaling is counteracted to maintain plant development under stress conditions remains largely unknown. Here, we show that SR45 overexpression reduces Arabidopsis sensitivity to ABA during early seedling development. Biochemical and confocal microscopy analyses of transgenic plants expressing fluorescently tagged SR45 revealed that exposure to ABA dephosphorylates the protein at multiple amino acid residues and leads to its accumulation, due to SR45 stabilization via reduced ubiquitination and proteasomal degradation. Using phosphomutant and phosphomimetic transgenic Arabidopsis lines, we demonstrate the functional relevance of ABA-mediated dephosphorylation of a single SR45 residue, T264, in antagonizing SR45 ubiquitination and degradation to promote its function as a repressor of seedling ABA sensitivity. Our results reveal a mechanism that negatively autoregulates ABA signaling and allows early plant growth under stress via posttranslational control of the SR45 splicing factor. Overexpression of the SR45 splicing factor, a negative regulator of the ABA stress signaling pathway, reduces plant sensitivity to the phytohormone. Exposure to ABA dephosphorylates SR45, leading to stabilization of the protein through reduced ubiquitination and proteasomal degradation. Our study reveals an autoregulatory mechanism for the alleviation of ABA-mediated inhibition of early plant growth under stress conditions.
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影响因子：
3.7
作者：
Breig O;Baklouti F
通讯作者：
Baklouti F
影响因子：
14.9
作者：
de la Fuente van Bentem, Sergio;Anrather, Dorothea;Roitinger, Elisabeth;Djamei, Armin;Hufnagl, Thomas;Barta, Andrea;Csaszar, Edina;Dohnal, Ilse;Lecourieux, David;Hirt, Heribert
通讯作者：
Hirt, Heribert
影响因子：
16.8
作者：
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影响因子：
2.8
作者：
Kiselev, Konstantin V.;Aleynova, Olga A.;Dubrovina, Alexandra S.
通讯作者：
Dubrovina, Alexandra S.
影响因子：
4.8
作者：
Golovkin, M;Reddy, ASN
通讯作者：
Reddy, ASN