Inositol hexakisphosphate kinases differentially regulate trafficking of vesicular glutamate transporters 1 and 2.
Inositol hexakisphosphate kinases differentially regulate trafficking of vesicular glutamate transporters 1 and 2.
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DOI：
10.3389/fncel.2022.926794
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发表时间：
2022
影响因子：
5.3
通讯作者：
中科院分区：
文献类型：
--
作者：
肌醇焦磷酸参与了细胞信号转导和膜转运，包括突触小泡(SV)的循环。肌醇六磷酸激酶(IP6Ks)及其产物二磷酸肌醇五磷酸(PP-IP5或IP7)通过活性依赖的批量内吞途径(ADBE)直接或间接调节在囊泡循环中重要的蛋白质。在本研究中，我们发现两种异构体IP6K1和IP6K3在轴突中表达。使用药物抑制、shRNA敲除和IP6K1和IP6K3基因敲除小鼠来研究这些激酶在SV循环中的作用。活细胞成像实验使用基于囊泡谷氨酸转运体异构体的SV循环的光学记录器，VGLUT1-和VGLUT2-pH luorins(PH)，这两种不同的循环。在温和的刺激条件下，VGLUT1-pH通过经典的AP-2依赖的内吞作用进行循环，而VGLUT2-pH也通过AP-1和AP-3接头蛋白进行循环。使用短刺激释放易释放池(RRP)，我们发现IP6K1 KO增加了VGLUT1-和VGLUT2-pH的胞吐，而IP6K3 KO减少了RRP中这两种转运体的数量。在电生理实验中，我们测量短刺激和在强烈刺激条件下触发大量内吞的谷氨酸信号。与野生型相比，IP6K1 KO可增强CA1区Schaffer侧支突触的突触易化作用，IP6K3 KO可降低突触易化作用。在强烈刺激后，通过敲除、敲除和药物抑制IP6Ks，VGLUT2-pH的内吞速率增加，但VGLUT1-pH的内吞速率不增加。因此，IP6K对使用不同内吞途径的两种SV蛋白的内吞作用有不同的影响。然而，IP6K1KO和IP6K3KO在刺激后的内吞作用中具有相似的作用，但在刺激早期的胞吐作用和谷氨酸释放的早期阶段，异构体对胞吐作用的影响不同。综上所述，这些数据表明，IP6K在刺激期早期的胞吐作用和内吞作用中都发挥了作用，特别是在可能利用AP-1/3适配器的条件下。
Inositol pyrophosphates have been implicated in cellular signaling and membrane trafficking, including synaptic vesicle (SV) recycling. Inositol hexakisphosphate kinases (IP6Ks) and their product, diphosphoinositol pentakisphosphate (PP-IP5 or IP7), directly and indirectly regulate proteins important in vesicle recycling by the activity-dependent bulk endocytosis pathway (ADBE). In the present study, we show that two isoforms, IP6K1 and IP6K3, are expressed in axons. The role of the kinases in SV recycling are investigated using pharmacologic inhibition, shRNA knockdown, and IP6K1 and IP6K3 knockout mice. Live-cell imaging experiments use optical reporters of SV recycling based on vesicular glutamate transporter isoforms, VGLUT1- and VGLUT2-pHluorins (pH), which recycle differently. VGLUT1-pH recycles by classical AP-2 dependent endocytosis under moderate stimulation conditions, while VGLUT2-pH recycles using AP-1 and AP-3 adaptor proteins as well. Using a short stimulus to release the readily releasable pool (RRP), we show that IP6K1 KO increases exocytosis of both VGLUT1-and VGLUT2-pH, while IP6K3 KO decreases the amount of both transporters in the RRP. In electrophysiological experiments we measure glutamate signaling with short stimuli and under the intense stimulation conditions that trigger bulk endocytosis. IP6K1 KO increases synaptic facilitation and IP6K3 KO decreases facilitation compared to wild type in CA1 hippocampal Schaffer collateral synapses. After intense stimulation, the rate of endocytosis of VGLUT2-pH, but not VGLUT1-pH, is increased by knockout, knockdown, and pharmacologic inhibition of IP6Ks. Thus IP6Ks differentially affect the endocytosis of two SV protein cargos that use different endocytic pathways. However, while IP6K1 KO and IP6K3 KO exert similar effects on endocytosis after stimulation, the isoforms exert different effects on exocytosis earlier in the stimulus and on the early phase of glutamate release. Taken together, the data indicate a role for IP6Ks both in exocytosis early in the stimulation period and in endocytosis, particularly under conditions that may utilize AP-1/3 adaptors.
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GLUT4 动员支持活跃突触的能量需求。
影响因子：
16.2
作者：
Ashrafi G;Wu Z;Farrell RJ;Ryan TA
通讯作者：
Ryan TA
影响因子：
64.5
作者：
Chakraborty A;Koldobskiy MA;Bello NT;Maxwell M;Potter JJ;Juluri KR;Maag D;Kim S;Huang AS;Dailey MJ;Saleh M;Snowman AM;Moran TH;Mezey E;Snyder SH
通讯作者：
Snyder SH
DOI：
10.1007/s11068-008-9030-y
发表时间：
2008-08-01
期刊：
BRAIN CELL BIOLOGY
影响因子：
--
作者：
Fernandez-Alfonso, Tomas;Ryan, Timothy A.
通讯作者：
Ryan, Timothy A.
影响因子：
--
作者：
Chakraborty A
通讯作者：
Chakraborty A
DOI：
10.1073/pnas.0909176106
发表时间：
2009-12-15
影响因子：
11.1
作者：
Azevedo, Cristina;Burton, Adam;Saiardi, Adolfo
通讯作者：
Saiardi, Adolfo