Abstract
The SNARE proteins involved in the secretion of neuromodulators from dense core vesicles (DCVs) in mammalian neurons are still poorly characterized. Here we use tetanus neurotoxin (TeNT) light chain, which cleaves VAMP1, 2 and 3, to study DCV fusion in hippocampal neurons and compare the effects on DCV fusion to those on synaptic vesicle (SV) fusion. Both DCV and SV fusion were abolished upon TeNT expression. Expression of tetanus insensitive (TI)-VAMP2 restored SV fusion in the presence of TeNT, but not DCV fusion. Expression of TI-VAMP1 or TI-VAMP3 also failed to restore DCV fusion. Co-transport assays revealed that both TI-VAMP1 and TI-VAMP2 are targeted to DCVs and travel together with DCVs in neurons. Furthermore, expression of the TeNT-cleaved VAMP2 fragment or a protease defective TeNT in wild type neurons did not affect DCV fusion and therefore cannot explain the lack of rescue of DCV fusion by TI-VAMP2. Finally, to test if two different VAMPs might both be required in the DCV secretory pathway, Vamp1 null mutants were tested. However, VAMP1 deficiency did not reduce DCV fusion. In conclusion, TeNT treatment combined with TI-VAMP2 expression differentially affects the two main regulated secretory pathways: while SV fusion is normal, DCV fusion is absent.
Original language | English |
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Article number | 10913 |
Pages (from-to) | 1-14 |
Number of pages | 14 |
Journal | Scientific Reports |
Volume | 10 |
Issue number | 1 |
Early online date | 2 Jul 2020 |
DOIs | |
Publication status | Published - 1 Dec 2020 |
Funding
The authors would like to thank Robert Zalm and Ingrid Saarloos for producing constructs and lentiviral particles, Joost Hoetjes for genotyping, Desiree Schut, Eline Kompanje, Lisa Laan and Frank den Oudsten for glial island production and support during culture, Joke Wortel for housing and breeding mice and Alessandro Moro for help with data analysis. This work is supported by an ERC Advanced Grant by the European Union (322966).
Funders | Funder number |
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Seventh Framework Programme | 322966 |
European Commission | |
European Research Council |