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Kim G, Lee SE, Jeong S, Lee J, Park D, Chang S. Multivalent electrostatic pi-cation interaction between synaptophysin and synapsin is responsible for the coacervation. Mol Brain 2021; 14:137. [PMID: 34496937 PMCID: PMC8424992 DOI: 10.1186/s13041-021-00846-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/24/2021] [Indexed: 12/26/2022] Open
Abstract
We recently showed that synaptophysin (Syph) and synapsin (Syn) can induce liquid-liquid phase separation (LLPS) to cluster small synaptic-like microvesicles in living cells which are highly reminiscent of SV cluster. However, as there is no physical interaction between them, the underlying mechanism for their coacervation remains unknown. Here, we showed that the coacervation between Syph and Syn is primarily governed by multivalent pi-cation electrostatic interactions among tyrosine residues of Syph C-terminal (Ct) and positively charged Syn. We found that Syph Ct is intrinsically disordered and it alone can form liquid droplets by interactions among themselves at high concentration in a crowding environment in vitro or when assisted by additional interactions by tagging with light-sensitive CRY2PHR or subunits of a multimeric protein in living cells. Syph Ct contains 10 repeated sequences, 9 of them start with tyrosine, and mutating 9 tyrosine to serine (9YS) completely abolished the phase separating property of Syph Ct, indicating tyrosine-mediated pi-interactions are critical. We further found that 9YS mutation failed to coacervate with Syn, and since 9YS retains Syph's negative charge, the results indicate that pi-cation interactions rather than simple charge interactions are responsible for their coacervation. In addition to revealing the underlying mechanism of Syph and Syn coacervation, our results also raise the possibility that physiological regulation of pi-cation interactions between Syph and Syn during synaptic activity may contribute to the dynamics of synaptic vesicle clustering.
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Affiliation(s)
- Goeun Kim
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Sang-Eun Lee
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea
- UK Dementia Research Institute, University College London, Cruciform Building, Gower St, London, WC1E 6BT, UK
| | - Seonyoung Jeong
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Jeongkun Lee
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Daehun Park
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Sunghoe Chang
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea.
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Borisova T, Pozdnyakova N, Krisanova N, Pastukhov A, Dudarenko M, Paliienko K, Grytsaenko V, Lux F, Lysenko V, Rocchi P, Komisarenko S, Tillement O. Unique features of brain metastases-targeted AGuIX nanoparticles vs their constituents: A focus on glutamate-/GABA-ergic neurotransmission in cortex nerve terminals. Food Chem Toxicol 2021; 149:112004. [PMID: 33482259 DOI: 10.1016/j.fct.2021.112004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/23/2020] [Accepted: 01/14/2021] [Indexed: 12/19/2022]
Abstract
Gadolinium-based radiosensitizing AGuIX nanoparticles (AGuIX) currently tested two phase 2 clinical trials in association with radiotherapy for the treatment of brain metastases. Here, excitatory/inhibitory neurotransmission was assessed in rat cortex nerve terminals in the presence of AGuIX and their constituents (DOTAGA and DOTAGA/Gd3+) at concentrations used for medical treatment, and those 5-24 times higher. The ambient level, transporter-mediated, tonic and exocytotic release of L-[14C]glutamate and [3H]GABA, the membrane potential of nerve terminals were not changed in the presence of AGuIX at concentrations used for medical treatment ([Gd3+] = 0.25 mM, corresponding to 0.25 g.L-1), and DOTAGA (0.25 mM) and DOTAGA/Gd3+ (0.25 mM/0.01 mM). Difference between AGuIX and the precursors was uncovered, when their concentrations were increased. AGuIX (1.25-6 mM) did not change any transport characteristics of L-[14C]glutamate and [3H]GABA, whereas, DOTAGA (1.25-6 mM) affected the membrane potential, ambient level, and exocytotic release of L-[14C]glutamate and [3H]GABA. Gd3+ did not mask, but even enhanced above effects of DOTAGA. Therefore, AGuIX did not influence glutamate- and GABA-ergic neurotransmission at the presynaptic site. In contrast, DOTAGA and mixture DOTAGA/Gd3+ significantly affected synaptic neurotransmission at high concentrations. AGuIX own structure that overcomes neurotoxic features of their constituents.
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Affiliation(s)
- Tatiana Borisova
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine.
| | - Natalia Pozdnyakova
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Natalia Krisanova
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Artem Pastukhov
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Marina Dudarenko
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Konstantin Paliienko
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Valeria Grytsaenko
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Francois Lux
- Light Matter Institute, UMR-5306, Claude Bernard University of Lyon/CNRS, Université de Lyon, 69622, Villeurbanne Cedex, France
| | - Vladimir Lysenko
- Light Matter Institute, UMR-5306, Claude Bernard University of Lyon/CNRS, Université de Lyon, 69622, Villeurbanne Cedex, France
| | - Paul Rocchi
- Light Matter Institute, UMR-5306, Claude Bernard University of Lyon/CNRS, Université de Lyon, 69622, Villeurbanne Cedex, France
| | - Serhiy Komisarenko
- Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kyiv, 01054, Ukraine
| | - Olivier Tillement
- Light Matter Institute, UMR-5306, Claude Bernard University of Lyon/CNRS, Université de Lyon, 69622, Villeurbanne Cedex, France
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