Rapid recycling of glutamate transporters on the astroglial surface
Glutamate uptake by astroglial transporters confines excitatory transmission to the synaptic cleft. The efficiency of this mechanism depends on the transporter dynamics in the astrocyte membrane, which remains poorly understood. Here, we visualise the main glial glutamate transporter GLT1 by generat...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2021-04-01
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| Series: | eLife |
| Subjects: | |
| Online Access: | https://elifesciences.org/articles/64714 |
| _version_ | 1811252964919083008 |
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| author | Piotr Michaluk Janosch Peter Heller Dmitri A Rusakov |
| author_facet | Piotr Michaluk Janosch Peter Heller Dmitri A Rusakov |
| author_sort | Piotr Michaluk |
| collection | DOAJ |
| description | Glutamate uptake by astroglial transporters confines excitatory transmission to the synaptic cleft. The efficiency of this mechanism depends on the transporter dynamics in the astrocyte membrane, which remains poorly understood. Here, we visualise the main glial glutamate transporter GLT1 by generating its pH-sensitive fluorescent analogue, GLT1-SEP. Fluorescence recovery after photobleaching-based imaging shows that 70–75% of GLT1-SEP dwell on the surface of rat brain astroglia, recycling with a lifetime of ~22 s. Genetic deletion of the C-terminus accelerates GLT1-SEP membrane turnover while disrupting its surface pattern, as revealed by single-molecule localisation microscopy. Excitatory activity boosts surface mobility of GLT1-SEP, involving its C-terminus, metabotropic glutamate receptors, intracellular Ca2+, and calcineurin-phosphatase activity, but not the broad-range kinase activity. The results suggest that membrane turnover, rather than lateral diffusion, is the main 'redeployment' route for the immobile fraction (20–30%) of surface-expressed GLT1. This finding reveals an important mechanism helping to control extrasynaptic escape of glutamate. |
| first_indexed | 2024-04-12T16:42:40Z |
| format | Article |
| id | doaj.art-d1962fc388a94469b4a954c88c06fb4a |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-12T16:42:40Z |
| publishDate | 2021-04-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-d1962fc388a94469b4a954c88c06fb4a2022-12-22T03:24:43ZengeLife Sciences Publications LtdeLife2050-084X2021-04-011010.7554/eLife.64714Rapid recycling of glutamate transporters on the astroglial surfacePiotr Michaluk0https://orcid.org/0000-0003-2306-3314Janosch Peter Heller1https://orcid.org/0000-0002-8825-3787Dmitri A Rusakov2https://orcid.org/0000-0001-9539-9947UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology PAS, Warsaw, PolandUCL Queen Square Institute of Neurology, University College London, London, United Kingdom; School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, IrelandUCL Queen Square Institute of Neurology, University College London, London, United KingdomGlutamate uptake by astroglial transporters confines excitatory transmission to the synaptic cleft. The efficiency of this mechanism depends on the transporter dynamics in the astrocyte membrane, which remains poorly understood. Here, we visualise the main glial glutamate transporter GLT1 by generating its pH-sensitive fluorescent analogue, GLT1-SEP. Fluorescence recovery after photobleaching-based imaging shows that 70–75% of GLT1-SEP dwell on the surface of rat brain astroglia, recycling with a lifetime of ~22 s. Genetic deletion of the C-terminus accelerates GLT1-SEP membrane turnover while disrupting its surface pattern, as revealed by single-molecule localisation microscopy. Excitatory activity boosts surface mobility of GLT1-SEP, involving its C-terminus, metabotropic glutamate receptors, intracellular Ca2+, and calcineurin-phosphatase activity, but not the broad-range kinase activity. The results suggest that membrane turnover, rather than lateral diffusion, is the main 'redeployment' route for the immobile fraction (20–30%) of surface-expressed GLT1. This finding reveals an important mechanism helping to control extrasynaptic escape of glutamate.https://elifesciences.org/articles/64714glutamate uptakesynaptic transmissionGLT-1Super-Ecliptic pHluorinastrocytesmembrane transport |
| spellingShingle | Piotr Michaluk Janosch Peter Heller Dmitri A Rusakov Rapid recycling of glutamate transporters on the astroglial surface eLife glutamate uptake synaptic transmission GLT-1 Super-Ecliptic pHluorin astrocytes membrane transport |
| title | Rapid recycling of glutamate transporters on the astroglial surface |
| title_full | Rapid recycling of glutamate transporters on the astroglial surface |
| title_fullStr | Rapid recycling of glutamate transporters on the astroglial surface |
| title_full_unstemmed | Rapid recycling of glutamate transporters on the astroglial surface |
| title_short | Rapid recycling of glutamate transporters on the astroglial surface |
| title_sort | rapid recycling of glutamate transporters on the astroglial surface |
| topic | glutamate uptake synaptic transmission GLT-1 Super-Ecliptic pHluorin astrocytes membrane transport |
| url | https://elifesciences.org/articles/64714 |
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