VGLUT2 Trafficking Is Differentially Regulated by Adaptor Proteins AP-1 and AP-3.
VGLUT2 Trafficking Is Differentially Regulated by Adaptor Proteins AP-1 and AP-3.
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DOI：
10.3389/fncel.2017.00324
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发表时间：
2017
影响因子：
5.3
通讯作者：
Voglmaier SM
中科院分区：
文献类型：
--
作者：
Li H;Santos MS;Park CK;Dobry Y;Voglmaier SM
突触囊泡胞吐释放主要兴奋性神经递质谷氨酸依赖于谷氨酸通过囊泡谷氨酸转运体（VGLUTs）装载到突触囊泡。两种主要亚型，VGLUT1和VGLUT2，在成人大脑中表现出一种互补的表达模式，广泛区分皮层（VGLUT1）和皮层下（VGLUT2）系统，并与表达这些亚型的突触中不同的生理特性相关。VGLUT1和vglut2的不同转运被认为是其功能多样性的基础。越来越多的证据表明，单个突触囊泡蛋白使用特定的分类信号来参与专门的生化机制来调节它们的循环。我们观察到VGLUT2在高频刺激下的循环与VGLUT1不同。在这里，我们使用基于氟的报告基因VGLUT2- ph进一步探讨了VGLUT2的贩运。与VGLUT1-pH相比，VGLUT2-pH表现出较慢的胞吐和内吞速率。在内源性主要表达VGLUT1的海马神经元和内源性主要表达VGLUT2的丘脑神经元中，VGLUT2- ph循环都比VGLUT1- ph慢，这表明控制分选的是蛋白质身份，而不是突触囊泡膜或神经元细胞类型。我们描述了在VGLUT2转运中起关键作用的c端二苯乙烯样基序中的分选信号。该基序的破坏消除了VGLUT2的突触靶向性，并从根本上消除了转运体的内吞作用。突变和生化分析表明，网格蛋白接头蛋白（APs）在二苯甲酸样基序上与VGLUT2相互作用。VGLUT2与AP-2相互作用，AP-2是一种被充分研究的网格蛋白介导的内吞作用的衔接蛋白。此外，VGLUT2还与备用适配器AP-1和AP-3相互作用。VGLUT2依赖于与VGLUT1不同的循环机制。药理学和分子抑制消除了这些差异，表明这些机制依赖于接头蛋白AP-1和AP-3。此外，shrna介导的敲低揭示了AP-1和AP-3在VGLUT2循环中的不同作用。
Release of the major excitatory neurotransmitter glutamate by synaptic vesicle exocytosis depends on glutamate loading into synaptic vesicles by vesicular glutamate transporters (VGLUTs). The two principal isoforms, VGLUT1 and 2, exhibit a complementary pattern of expression in adult brain that broadly distinguishes cortical (VGLUT1) and subcortical (VGLUT2) systems, and correlates with distinct physiological properties in synapses expressing these isoforms. Differential trafficking of VGLUT1 and 2 has been suggested to underlie their functional diversity. Increasing evidence suggests individual synaptic vesicle proteins use specific sorting signals to engage specialized biochemical mechanisms to regulate their recycling. We observed that VGLUT2 recycles differently in response to high frequency stimulation than VGLUT1. Here we further explore the trafficking of VGLUT2 using a pHluorin-based reporter, VGLUT2-pH. VGLUT2-pH exhibits slower rates of both exocytosis and endocytosis than VGLUT1-pH. VGLUT2-pH recycling is slower than VGLUT1-pH in both hippocampal neurons, which endogenously express mostly VGLUT1, and thalamic neurons, which endogenously express mostly VGLUT2, indicating that protein identity, not synaptic vesicle membrane or neuronal cell type, controls sorting. We characterize sorting signals in the C-terminal dileucine-like motif, which plays a crucial role in VGLUT2 trafficking. Disruption of this motif abolishes synaptic targeting of VGLUT2 and essentially eliminates endocytosis of the transporter. Mutational and biochemical analysis demonstrates that clathrin adaptor proteins (APs) interact with VGLUT2 at the dileucine-like motif. VGLUT2 interacts with AP-2, a well-studied adaptor protein for clathrin mediated endocytosis. In addition, VGLUT2 also interacts with the alternate adaptors, AP-1 and AP-3. VGLUT2 relies on distinct recycling mechanisms from VGLUT1. Abrogation of these differences by pharmacological and molecular inhibition reveals that these mechanisms are dependent on the adaptor proteins AP-1 and AP-3. Further, shRNA-mediated knockdown reveals differential roles for AP-1 and AP-3 in VGLUT2 recycling.
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DOI：
10.1083/jcb.201310021
发表时间：
2014-01-06
期刊：
The Journal of cell biology
影响因子：
--
作者：
Bonifacino JS
通讯作者：
Bonifacino JS
影响因子：
2.5
作者：
Boulland, JL;Qureshi, T;Chaudhry, FA
通讯作者：
Chaudhry, FA
影响因子：
56.9
作者：
Bellocchio, EE;Reimer, RJ;Edwards, RH
通讯作者：
Edwards, RH
影响因子：
5.3
作者：
Balaji, J.;Armbruster, Moritz;Ryan, Timothy A.
通讯作者：
Ryan, Timothy A.
影响因子：
3.5
作者：
Ariel, Pablo;Ryan, Timothy A.
通讯作者：
Ryan, Timothy A.