The dynein light chain protein Tda2 functions as a dimerization engine to regulate actin capping protein during endocytosis.
The dynein light chain protein Tda2 functions as a dimerization engine to regulate actin capping protein during endocytosis.
复制标题
动力蛋白轻链蛋白Tda2作为二聚化引擎在内吞过程中调节肌动蛋白封盖蛋白。
DOI：
10.1091/mbc.e21-01-0032
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发表时间：
2021-08-01
影响因子：
3.3
通讯作者：
Di Pietro SM
中科院分区：
文献类型：
--
作者：
Lamb AK;Fernandez AN;Peersen OB;Di Pietro SM
网格蛋白和肌动蛋白介导的胞吞作用是真核细胞的一个基本过程。之前，我们发现Tda2是一种新的酵母动力蛋白轻链（DLC），它与Aim21一起调节内吞过程中的肌动蛋白组装。在这里，我们展示了Tda2作为二聚化引擎的功能，通过一种不同于典型DLC配体结合槽的新型结合表面将两个Aim21分子结合在一起。在体外减少TDA2 - aim21相互作用的两种蛋白上的点突变导致与TDA2缺失相同的体内表型，显示肌动蛋白封盖蛋白（CP）募集减少和内噬部位丝状肌动蛋白增加。值得注意的是，化学诱导的Aim21二聚化恢复了TDA2缺失的内吞表型。我们还在Aim21中发现了一个CP相互作用基序，将其功能扩展到一个基本的细胞通路，并表明该基序存在于哺乳动物细胞外。此外，该基序的特异性破坏导致与AIM21缺失相同的肌动蛋白CP招募缺陷和内吞位点丝状肌动蛋白增加。因此，这些数据表明Tda2-Aim21复合物主要通过CP调控在肌动蛋白组装中起作用。总的来说，我们的研究结果提供了Tda2-Aim21复合物及其在内吞部位肌动蛋白网络调节中的功能的机制观点。
Clathrin- and actin-mediated endocytosis is a fundamental process in eukaryotic cells. Previously, we discovered Tda2 as a new yeast dynein light chain (DLC) that works with Aim21 to regulate actin assembly during endocytosis. Here we show Tda2 functions as a dimerization engine bringing two Aim21 molecules together using a novel binding surface different than the canonical DLC ligand binding groove. Point mutations on either protein that diminish the Tda2-Aim21 interaction in vitro cause the same in vivo phenotype as TDA2 deletion showing reduced actin capping protein (CP) recruitment and increased filamentous actin at endocytic sites. Remarkably, chemically induced dimerization of Aim21 rescues the endocytic phenotype of TDA2 deletion. We also uncovered a CP interacting motif in Aim21, expanding its function to a fundamental cellular pathway and showing such motif exists outside mammalian cells. Furthermore, specific disruption of this motif causes the same deficit of actin CP recruitment and increased filamentous actin at endocytic sites as AIM21 deletion. Thus, the data indicate the Tda2-Aim21 complex functions in actin assembly primarily through CP regulation. Collectively, our results provide a mechanistic view of the Tda2-Aim21 complex and its function in actin network regulation at endocytic sites.