The Actin Nucleator Cobl Is Crucial for Purkinje Cell Development and Works in Close Conjunction with the F-Actin Binding Protein Abp1
The Actin Nucleator Cobl Is Crucial for Purkinje Cell Development and Works in Close Conjunction with the F-Actin Binding Protein Abp1
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DOI：
10.1523/jneurosci.0843-12.2012
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发表时间：
2012-12-05
影响因子：
5.3
通讯作者：
Kessels, Michael M.
中科院分区：
文献类型：
--
作者：
Haag, Natja;Schwintzer, Lukas;Kessels, Michael M.
皮质肌动蛋白动力学塑造细胞。为了产生肌动蛋白丝，细胞依靠肌动蛋白成核器。Cobl是一种新颖的，富含大脑的，基于WH2结构域的肌动蛋白成核子，然而，它的功能在很大程度上仍然是难以捉摸的。在这里，我们揭示了Cobl在完整小鼠小脑环境中基因枪转染浦肯野细胞发育中起着至关重要的作用。钴缺乏损害了浦肯野细胞的树突状树突形成，导致树突状树突形成低复杂性的树突。分支点数和密度，特别是高阶分支受到强烈影响。我们努力揭示Cobl如何在物理和功能上整合到皮质肌动蛋白细胞骨架中，结果表明，所有Cobl功能丧失表型都精确地反映在f-肌动蛋白结合蛋白Abp1的敲低上。通过亚细胞分离、蛋白质相互作用分析、蛋白质复合物的亚细胞重构、细胞和组织中的共定位研究以及神经元形态发生的功能分析，我们证明了这两种蛋白质密切相关并相互作用。cob介导的海马神经元树突分支诱导严重依赖于Abp1。我们的研究强调了Abp1的功能与Cobl结合蛋白syndapin i的功能不同。功能拯救实验强调了Cobl/Abp1复合物形成和Abp1介导的F-actin关联的重要性，表明缺乏Abp1结合的Cobl突变体和支持Cobl关联但缺乏F-actin结合能力的Abp1突变体未能拯救各自的功能丧失表型。因此，f -肌动蛋白锚定的Cobl/Abp1复合物似乎对神经形态发生过程至关重要，特别是对出生后代表小脑皮层所有运动协调来源的浦肯野细胞的树突。
Cortical actin dynamics shapes cells. To generate actin filaments, cells rely on actin nucleators. Cobl is a novel, brain-enriched, WH2 domain-based actin nucleator, yet, its functions remained largely elusive. Here, we reveal that Cobl plays a crucial role in Purkinje cell development using gene gun transfections within intact murine cerebellar contexts. Cobl deficiency impaired proper dendritic arborization of Purkinje cells and led to low-complexity arbors. Branch point numbers and density and especially higher order branching were strongly affected. Our efforts to reveal how Cobl is physically and functionally integrated into the cortical actin cytoskeleton showed that all Cobl loss-of-function phenotypes were exactly mirrored by knockdown of the F-actin-binding protein Abp1. By subcellular fractionations, protein interaction analyses, subcellular reconstitutions of protein complexes, colocalization studies in cells and tissues, and by functional analyses in neuronal morphogenesis we demonstrate that both proteins associate and work with each other closely. Cobl-mediated dendritic branch induction in hippocampal neurons critically relied on Abp1. Our study highlights that the functions of Abp1 are distinct from those of the Cobl-binding protein syndapin I. The importance of Cobl/Abp1 complex formation and of Abp1-mediated F-actin association was highlighted by functional rescue experiments demonstrating that a Cobl mutant deficient for Abp1 binding and an Abp1 mutant supporting Cobl association but lacking the F-actin binding ability failed to rescue the respective loss-of-function phenotypes. Thus, F-actin-anchored Cobl/Abp1 complexes seem crucial for neuromorphogenesis processes, particularly for the postnatal arborization of Purkinje cells representing the source for all motor coordination in the cerebellar cortex.