Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Nonnenplan 2-4, 07743 Jena, Germany.
Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark.
Dev Cell. 2018 Apr 23;45(2):262-275.e8. doi: 10.1016/j.devcel.2018.03.007.
The complex architecture of neuronal networks in the brain requires tight control of the actin cytoskeleton. The actin nucleator Cobl is critical for neuronal morphogenesis. Here we reveal that Cobl is controlled by arginine methylation. Coprecipitations, coimmunoprecipitations, cellular reconstitutions, and in vitro reconstitutions demonstrated that Cobl associates with the protein arginine methyltransferase PRMT2 in a Src Homology 3 (SH3) domain-dependent manner and that this promotes methylation of Cobl's actin nucleating C-terminal domain. Consistently, PRMT2 phenocopied Cobl functions in both gain- and loss-of-function studies. Both PRMT2- and Cobl-promoted dendritogenesis relied on methylation. PRMT2 effects require both its catalytic domain and SH3 domain. Cobl-mediated dendritic arborization required PRMT2, complex formation with PRMT2, and PRMT2's catalytic activity. Mechanistic studies reveal that Cobl methylation is key for Cobl actin binding. Therefore, arginine methylation is a regulatory mechanism reaching beyond controlling nuclear processes. It also controls a major, cytosolic, cytoskeletal component shaping neuronal cells.
大脑中神经元网络的复杂结构需要严格控制肌动蛋白细胞骨架。肌动蛋白成核因子 Cobl 对神经元形态发生至关重要。在这里，我们揭示 Cobl 受精氨酸甲基化调控。共沉淀、共免疫沉淀、细胞重建和体外重建表明，Cobl 与蛋白精氨酸甲基转移酶 PRMT2 以Src 同源 3（SH3）结构域依赖性的方式结合，并且促进 Cobl 的肌动蛋白成核 C 末端结构域的甲基化。一致地，PRMT2 在功能获得和功能丧失研究中均模拟了 Cobl 的功能。PRMT2 和 Cobl 促进树突发生都依赖于甲基化。PRMT2 的作用需要其催化结构域和 SH3 结构域。Cobl 介导的树突分支需要 PRMT2、与 PRMT2 的复合物形成以及 PRMT2 的催化活性。机制研究表明，Cobl 甲基化是 Cobl 肌动蛋白结合的关键。因此，精氨酸甲基化是一种超越核过程调控的调控机制。它还控制着塑造神经元细胞的主要细胞质、细胞骨架成分。
