Functional non-equivalence of pollen ADF isovariants in Arabidopsis
Functional non-equivalence of pollen ADF isovariants in Arabidopsis
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DOI：
10.1111/tpj.15723
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发表时间：
2022-03-14
期刊：
影响因子：
7.2
通讯作者：
Huang, Shanjin
中科院分区：
文献类型：
--
作者：
Jiang, Yuxiang;Lu, Qiaonan;Huang, Shanjin
肌动蛋白解聚因子/丝切蛋白（ADF/cofilin）是肌动蛋白动力学的核心调节因子。我们之前已证实，拟南芥中两个密切相关的IIa类ADF异构体ADF7和ADF10参与促进花粉中肌动蛋白的周转，但它们是否具有不同功能仍不清楚。在此，我们进一步证明，它们在体外和体内对肌动蛋白周转的调节中表现出不同功能。我们发现，与ADF10相比，ADF7与ADP - G - 肌动蛋白的结合亲和力较低，并且在体外切断和解聚肌动蛋白丝的效率也较低。相应地，在花粉粒中，与ADF10相比，ADF7更广泛地修饰肌动蛋白丝，且在细胞质中的自由分布较少。我们进一步证明，在花粉萌发过程中，ADF7和ADF10呈现出不同的细胞内定位，并且它们在促进花粉中肌动蛋白周转方面具有不等同的功能。因此，我们提出ADF7和ADF10的协同与分工，使花粉细胞能够精确控制不同肌动蛋白结构的周转，以满足不同的细胞需求。
ADF/cofilin is a central regulator of actin dynamics. We previously demonstrated that two closely related Arabidopsis class IIa ADF isovariants, ADF7 and ADF10, are involved in the enhancement of actin turnover in pollen, but whether they have distinct functions remains unknown. Here, we further demonstrate that they exhibit distinct functions in regulating actin turnover both in vitro and in vivo. We found that ADF7 binds to ADP-G-actin with lower affinity, and severs and depolymerizes actin filaments less efficiently in vitro than ADF10. Accordingly, in pollen grains, ADF7 more extensively decorates actin filaments and is less freely distributed in the cytoplasm compared to ADF10. We further demonstrate that ADF7 and ADF10 show distinct intracellular localizations during pollen germination, and they have non-equivalent functions in promoting actin turnover in pollen. We thus propose that cooperation and labor division of ADF7 and ADF10 enable pollen cells to achieve exquisite control of the turnover of different actin structures to meet different cellular needs.