Terry-Lorenzo Ryan T, Torres Viviana I, Wagh Dhananjay, Galaz Jose, Swanson Selene K, Florens Laurence, Washburn Michael P, Waites Clarissa L, Gundelfinger Eckart D, Reimer Richard J, Garner Craig C
Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America.
Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, Alameda, Santiago, Chile.
PLoS One. 2016 Dec 1;11(12):e0167535. doi: 10.1371/journal.pone.0167535. eCollection 2016.
Synaptic vesicles (SVs) fuse with the plasma membrane at a precise location called the presynaptic active zone (AZ). This fusion is coordinated by proteins embedded within a cytoskeletal matrix assembled at the AZ (CAZ). In the present study, we have identified a novel binding partner for the CAZ proteins Piccolo and Bassoon. This interacting protein, Trio, is a member of the Dbl family of guanine nucleotide exchange factors (GEFs) known to regulate the dynamic assembly of actin and growth factor dependent axon guidance and synaptic growth. Trio was found to interact with the C-terminal PBH 9/10 domains of Piccolo and Bassoon via its own N-terminal Spectrin repeats, a domain that is also critical for its localization to the CAZ. Moreover, our data suggest that regions within the C-terminus of Trio negatively regulate its interactions with Piccolo/Bassoon. These findings provide a mechanism for the presynaptic targeting of Trio and support a model in which Piccolo and Bassoon play a role in regulating neurotransmission through interactions with proteins, including Trio, that modulate the dynamic assembly of F-actin during cycles of synaptic vesicle exo- and endocytosis.
突触小泡（SVs）在一个被称为突触前活性区（AZ）的精确位置与质膜融合。这种融合由嵌入在AZ处组装的细胞骨架基质（CAZ）中的蛋白质协调。在本研究中，我们鉴定出了一种与CAZ蛋白 piccolo 和 Bassoon 结合的新伴侣。这种相互作用蛋白 Trio 是鸟嘌呤核苷酸交换因子（GEFs）的 Dbl 家族成员，已知其可调节肌动蛋白的动态组装以及生长因子依赖性轴突导向和突触生长。发现 Trio 通过其自身的 N 端血影蛋白重复序列与 piccolo 和 Bassoon 的 C 端 PBH 9/10 结构域相互作用，该结构域对于其定位于 CAZ 也至关重要。此外，我们的数据表明 Trio C 端内的区域对其与 piccolo/Bassoon 的相互作用具有负调节作用。这些发现为 Trio 的突触前靶向提供了一种机制，并支持了一种模型，即 piccolo 和 Bassoon 通过与包括 Trio 在内的蛋白质相互作用在调节神经传递中发挥作用，这些蛋白质在突触小泡胞吐和内吞循环期间调节 F-肌动蛋白的动态组装。
