Astrocyte VAMP3 vesicles undergo Ca2+-independent cycling and modulate glutamate transporter trafficking

作者：Li Dongdong; Herault Karine; Zylbersztejn Kathleen; Lauterbach Marcel A; Guillon Marc; Oheim Martin; Ropert Nicole

来源：The Journal of Physiology, 2015, 593(13): 2807-2832.

DOI：10.1113/JP270362

KEY POINTS: Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 vesicles undergo Ca(2+) -independent exo- and endocytotic cycling at the plasma membrane. VAMP3 vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 vesicle cycling and glutamate uptake. ABSTRACT: Previous studies suggest that small synaptic-like vesicles in astrocytes carry vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca(2+) -regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 vesicles were studied in cultured astrocytes at single vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter ( approximately 80 nm) vesicles and that VAMP3 vesicles undergo Ca(2+) -independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 vesicles in astrocytes.

• 出版日期2015-7-1
• 单位常州工学院