Department of Biosciences, Durham University, South road, Durham, DH1 3LE, UK.
College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China.
J Exp Bot. 2017 Mar 1;68(7):1441-1450. doi: 10.1093/jxb/erx047.
In plants movement of the endoplasmic reticulum (ER) is dependent on the actin cytoskeleton. However little is known about proteins that link the ER membrane and the actin cytoskeleton. Here we identified a novel protein, NETWORKED 3B (NET3B), which is associated with the ER and actin cytoskeleton in vivo. NET3B belongs to a superfamily of plant specific actin binding proteins, the NETWORKED family. NET3B associates with the actin cytoskeleton in vivo through an N-terminal NET actin binding (NAB) domain, which has been well-characterized in other members of the NET family. A three amino acid insertion, Val-Glu-Asp, in the NAB domain of NET3B appears to lower its ability to localize to the actin cytoskeleton compared with NET1A, the founding member of the NET family. The C-terminal domain of NET3B links the protein to the ER. Overexpression of NET3B enhanced the association between the ER and the actin cytoskeleton, and the extent of this association was dependent on the amount of NET3B available. Another effect of NET3B overexpression was a reduction in ER membrane diffusion. In conclusion, our results revealed that NET3B modulates ER and actin cytoskeleton interactions in higher plants.
在植物中，内质网（ER）的运动依赖于肌动蛋白细胞骨架。然而，对于连接 ER 膜和肌动蛋白细胞骨架的蛋白质知之甚少。在这里，我们鉴定了一种新的蛋白质，NETWORKED 3B（NET3B），它在体内与 ER 和肌动蛋白细胞骨架相关联。NET3B 属于植物特异性肌动蛋白结合蛋白的超家族，即 NETWORKED 家族。NET3B 通过其 N 端 NET 肌动蛋白结合（NAB）结构域与肌动蛋白细胞骨架在体内相互作用，该结构域在 NET 家族的其他成员中已得到很好的描述。NET3B 的 NAB 结构域中存在三个氨基酸插入（Val-Glu-Asp），这似乎降低了它与肌动蛋白细胞骨架定位的能力，与 NET 家族的创始成员 NET1A 相比。NET3B 的 C 端结构域将蛋白质与 ER 连接起来。过表达 NET3B 增强了 ER 和肌动蛋白细胞骨架之间的关联，并且这种关联的程度取决于 NET3B 的可用量。NET3B 过表达的另一个影响是 ER 膜扩散减少。总之，我们的结果表明 NET3B 调节高等植物中 ER 和肌动蛋白细胞骨架的相互作用。
