SYN2

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0030672 synaptic vesicle membrane	IBA GO_REF:0000033	ACCEPT	Summary: Synapsin-2 is a peripheral membrane protein that associates with the cytosolic face of synaptic vesicle membranes via its N-terminal domains (A-C domains). The deep research confirms SYN2 is "enriched at presynaptic boutons and axons; peripherally associated with SV membranes on the cytosolic side" [Longfield et al. 2024, Stavsky et al. 2024]. UniProt describes it as a protein that "coats synaptic vesicles" and notes the A region "binds phospholipids with a preference for negatively charged species." Reason: Core localization annotation supported by IBA phylogenetic inference and strongly corroborated by literature showing SYN2 peripheral association with synaptic vesicle membranes. Supporting Evidence: DOI:10.1038/s41467-024-46256-1 Synapsin-2 is enriched at presynaptic boutons and axons; peripherally associated with SV membranes on the cytosolic side
GO:0097091 synaptic vesicle clustering	IBA GO_REF:0000033	ACCEPT	Summary: Synaptic vesicle clustering is the primary molecular function of SYN2. Multiple 2023-2024 studies demonstrate SYN2 clusters synaptic vesicles into a reserve pool through tetramerization and LLPS mechanisms. The deep research states "SYN2 clusters synaptic vesicles, maintains the reserve pool (RP), regulates mobilization and neurotransmitter release" [Bruentgens et al. 2023, Longfield et al. 2024]. Reason: Core biological process annotation. Synaptic vesicle clustering is the primary function of SYN2, supported by extensive recent literature demonstrating both LLPS and tetramerization-dependent clustering mechanisms. Supporting Evidence: DOI:10.1038/s41467-024-46256-1 Syn2aWT fully rescued the elevated mobility of reserve SVs, whereas a tetramerization-deficient Syn2a K337Q mutant failed to rescue DOI:10.1101/2023.08.08.549335 SYN2 clusters synaptic vesicles into a reserve pool, modulates their mobility, and thereby supports sustained neurotransmission
GO:0050808 synapse organization	IBA GO_REF:0000033	ACCEPT	Summary: SYN2 contributes to synapse organization through its role in organizing the presynaptic vesicle pools. The deep research indicates synapsins shape "mesoscale SV organization" and are involved in "synapsin-organized mesoscale SV architecture" [Bruentgens et al. 2023]. This is a broader parent term of synaptic vesicle clustering. Reason: Valid broader annotation. SYN2 contributes to synapse organization through organizing the presynaptic vesicle pool architecture, though GO:0097091 (synaptic vesicle clustering) is more specific and informative. Supporting Evidence: DOI:10.1101/2023.08.08.549335 synapsin-organized mesoscale SV architecture in plasticity expression
GO:0005524 ATP binding	IEA GO_REF:0000002	ACCEPT	Summary: SYN2 contains an ATP-grasp domain (IPR013815) and ATP-binding domain (IPR020898). The deep research confirms ATP modulates synapsin function: "ATP within physiological ranges inhibits LLPS (half-max ~1.7 mM for Syn2a) and favors higher-order oligomerization" [Song & Augustine 2023]. This functional ATP interaction is well documented. Reason: Valid IEA annotation based on domain content. The ATP-grasp domain is present in SYN2 and ATP binding is functionally relevant - ATP modulates the balance between LLPS and oligomerization states. Supporting Evidence: DOI:10.1101/2023.03.20.533583 Half-maximal inhibition of Syn2a LLPS by ATP occurred near ~1.7 mM
GO:0007268 chemical synaptic transmission	IEA GO_REF:0000117	ACCEPT	Summary: SYN2 is involved in chemical synaptic transmission by regulating synaptic vesicle availability for neurotransmitter release. Deep research states SYN2 "regulates their mobility, and thereby supports sustained neurotransmission" [Bruentgens et al. 2023]. Reason: Valid annotation. SYN2 participates in chemical synaptic transmission by regulating the reserve pool and vesicle availability for release, supporting sustained neurotransmission. Supporting Evidence: DOI:10.1101/2023.08.08.549335 clusters SVs into a reserve pool, modulates their mobility, and thereby supports sustained neurotransmission
GO:0007269 neurotransmitter secretion	IEA GO_REF:0000002	ACCEPT	Summary: SYN2 regulates neurotransmitter secretion by controlling vesicle availability through reserve pool organization. UniProt states it is "believed to function in the regulation of neurotransmitter release" and "may play a role in noradrenaline secretion by sympathetic neurons." Reason: Valid annotation supported by domain inference and literature. SYN2 indirectly regulates neurotransmitter secretion by controlling vesicle pool organization and mobilization. Supporting Evidence: PMID:15217342 synaptic vesicles undergo a trafficking cycle... leads to the docking and priming of the vesicles for another round of exo- and endocytosis
GO:0008021 synaptic vesicle	IEA GO_REF:0000002	ACCEPT	Summary: SYN2 is a synaptic vesicle-associated protein that peripherally coats vesicles on their cytosolic surface. Deep research confirms "SYN2 is a presynaptic SV-associated scaffold" [Song & Augustine 2023, Longfield et al. 2024]. Reason: Valid localization annotation. SYN2 is physically associated with synaptic vesicles as a peripheral membrane protein. Supporting Evidence: DOI:10.1038/s41467-024-46256-1 presynaptic, cytosolic synaptic vesicle (SV)-associated phosphoprotein
GO:0045202 synapse	IEA GO_REF:0000120	ACCEPT	Summary: SYN2 localizes to synapses, specifically to presynaptic terminals. UniProt lists subcellular location as "Synapse." This is a broader parent term; more specific terms like synaptic vesicle membrane are more informative. Reason: Valid but general localization annotation. More specific CC terms like GO:0030672 (synaptic vesicle membrane) are preferred.
GO:0005515 protein binding	IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling...	MODIFY	Summary: This annotation derives from the BioPlex 3.0 interactome study showing SYN2 interaction with SYN3 (O14994) in high-throughput affinity purification mass spectrometry. While the interaction is likely real given synapsin family members are known to oligomerize, "protein binding" is uninformative. Reason: The term "protein binding" does not convey meaningful information about SYN2 function. The interaction with SYN3 reflects the oligomerization property of synapsins which is central to their vesicle clustering function. Proposed replacements: identical protein binding Supporting Evidence: DOI:10.1038/s41467-024-46256-1 Synapsin-2a can tetramerize, and this assembly property is central to reserve-pool organization
GO:0005515 protein binding	IPI PMID:40205054 Multimodal cell maps as a foundation for structural and func...	MODIFY	Summary: This annotation derives from multimodal cell maps study showing SYN2-SYN3 interaction. Same issue as PMID:33961781 - "protein binding" is uninformative. The interaction reflects synapsin oligomerization. Reason: "Protein binding" does not convey meaningful functional information. Should be annotated with more specific term reflecting homo/hetero- oligomerization of synapsin family members. Proposed replacements: identical protein binding Supporting Evidence: DOI:10.1038/s41467-024-46256-1 tetramerization (prominently via Synapsin-2a) expands RP size and accelerates mobilization
GO:0005886 plasma membrane	IEA GO_REF:0000107	MARK AS OVER ANNOTATED	Summary: SYN2 is primarily a synaptic vesicle-associated protein, not a plasma membrane protein. The annotation likely derives from orthology transfer but may reflect transient plasma membrane association during vesicle fusion/recycling. Reason: SYN2 is primarily associated with synaptic vesicles in the cytosol, not the plasma membrane. Any plasma membrane association would be transient during vesicle fusion. The core localization is synaptic vesicle membrane (GO:0030672).
GO:0014069 postsynaptic density	IEA GO_REF:0000107	REMOVE	Summary: SYN2 is canonically a presynaptic protein that associates with synaptic vesicles. Postsynaptic localization would be unexpected given its known function in vesicle clustering and mobilization. This may be an artifact of orthology transfer or contamination in proteomic studies. Reason: SYN2 is a presynaptic protein. All literature and deep research consistently describe it as "presynaptic" and associated with synaptic vesicles at the cytosolic face. Postsynaptic density localization is not consistent with its established function.
GO:0017156 calcium-ion regulated exocytosis	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: SYN2 is phosphorylated in response to calcium signaling (by CaMKII) and this regulates vesicle mobilization. However, SYN2 is not directly involved in the calcium-triggered exocytosis machinery but rather in regulating the availability of vesicles for release. Reason: SYN2 indirectly supports calcium-regulated exocytosis by making vesicles available through reserve pool regulation, but it is not part of the core calcium-sensing or fusion machinery. Its primary role is vesicle clustering and mobilization.
GO:0030672 synaptic vesicle membrane	IEA GO_REF:0000107	ACCEPT	Summary: Duplicate annotation for synaptic vesicle membrane via orthology transfer. Same as IBA annotation - SYN2 is peripherally associated with synaptic vesicle membranes. Reason: Valid CC annotation, consistent with IBA annotation and literature. Duplicates with different evidence codes are acceptable.
GO:0031201 SNARE complex	IEA GO_REF:0000107	REMOVE	Summary: SYN2 is not a component of the SNARE complex. The SNARE complex consists of SNAP-25, syntaxin, and VAMP/synaptobrevin. SYN2 functions upstream in vesicle clustering/mobilization, not in the fusion machinery itself. Reason: SYN2 is not a SNARE protein and is not part of the SNARE complex. This is likely an erroneous annotation from orthology transfer. SYN2 regulates vesicle pools but is not directly part of the fusion machinery.
GO:0042802 identical protein binding	IEA GO_REF:0000107	ACCEPT	Summary: SYN2 can form oligomers including tetramers (Syn2a isoform specifically). The deep research confirms "Synapsin-2a can tetramerize, and this assembly property is central to reserve-pool organization" [Longfield et al. 2024]. Reason: Valid MF annotation supported by literature. Syn2a tetramerization is well-documented and functionally important for vesicle clustering. More specific than generic "protein binding." Supporting Evidence: DOI:10.1038/s41467-024-46256-1 Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles
GO:0097091 synaptic vesicle clustering	IEA GO_REF:0000107	ACCEPT	Summary: Duplicate annotation for synaptic vesicle clustering via orthology transfer. Same as IBA annotation - this is a core function of SYN2. Reason: Valid BP annotation consistent with IBA annotation and core function of SYN2. Duplicates with different evidence codes are acceptable.
GO:0098685 Schaffer collateral - CA1 synapse	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: SYN2 is expressed in hippocampal neurons including Schaffer collateral synapses. This is a very specific synapse-type annotation that reflects expression data rather than specific function at this synapse type. Reason: While SYN2 is likely present at Schaffer collateral synapses as a broadly expressed synaptic vesicle protein, this specific synapse-type annotation adds limited functional insight beyond general synaptic localization.
GO:0098978 glutamatergic synapse	IEA GO_REF:0000107	ACCEPT	Summary: SYN2 functions at both glutamatergic (excitatory) and GABAergic (inhibitory) synapses, but with different mechanisms. Deep research shows "at excitatory synapses, tetramerization (prominently via Synapsin-2a) expands RP size" [Song & Augustine 2023]. Reason: Valid localization. SYN2 (particularly Syn2a via tetramerization) functions at glutamatergic synapses to organize the reserve pool. However, SYN2 also functions at inhibitory synapses. Supporting Evidence: DOI:10.1101/2023.03.20.533583 at excitatory synapses, tetramerization (prominently via Synapsin-2a) expands RP size and accelerates mobilization
GO:0099504 synaptic vesicle cycle	IEA GO_REF:0000107	ACCEPT	Summary: SYN2 integrates with the synaptic vesicle cycle by regulating reserve pool size and vesicle mobilization. Deep research states SYN2 "integrates with the SV cycle as a regulator of RP size and mobilization kinetics" [Stavsky et al. 2024]. Reason: Valid BP annotation. SYN2 is a key regulator of the synaptic vesicle cycle, specifically at the reserve pool mobilization step. Supporting Evidence: DOI:10.7554/eLife.89687 Synapsin-2 integrates with the SV cycle as a regulator of RP size and mobilization kinetics
GO:0005515 protein binding	IPI PMID:23406870 Epileptogenic Q555X SYN1 mutant triggers imbalances in relea...	MODIFY	Summary: This annotation derives from co-immunoprecipitation experiments showing SYN1 (P17600) oligomerizes with SYN2 isoforms (SynIIa and SynIIb). The paper states "We found that the Q555X truncation virtually abolished the ability of SynI to interact with SynIIa and strongly reduced the interaction with SynIIb. These data indicate that SynI/SynII hetero-oligomerization, which is thought to play an important role in SV clustering, is strongly affected by the mutation." Reason: The interaction is well documented but "protein binding" is uninformative. This represents hetero-oligomerization between synapsin family members which is functionally important for vesicle clustering. Proposed replacements: identical protein binding Supporting Evidence: PMID:23406870 We found that the Q555X truncation virtually abolished the ability of SynI to interact with SynIIa and strongly reduced the interaction with SynIIb. These data indicate that SynI/SynII hetero-oligomerization, which is thought to play an important role in SV clustering, is strongly affected by the mutation.
GO:0007269 neurotransmitter secretion	ISS GO_REF:0000024	ACCEPT	Summary: ISS annotation from mouse ortholog Q64332. SYN2 regulates neurotransmitter secretion indirectly by controlling vesicle availability. Consistent with the IEA annotation. Reason: Valid annotation supported by sequence similarity to characterized mouse ortholog and consistent with SYN2 function in vesicle pool regulation.
GO:0030672 synaptic vesicle membrane	ISS GO_REF:0000024	ACCEPT	Summary: ISS annotation from mouse ortholog. SYN2 is peripherally associated with synaptic vesicle membranes. Consistent with IBA and IEA annotations. Reason: Valid CC annotation consistent with other evidence codes and literature.
GO:0045202 synapse	ISS GO_REF:0000024	ACCEPT	Summary: ISS annotation from mouse ortholog. SYN2 localizes to synapses, specifically presynaptic terminals. Consistent with IEA annotation. Reason: Valid but general CC annotation. More specific terms like synaptic vesicle membrane are preferred.
GO:0005524 ATP binding	TAS PMID:15217342 The synaptic vesicle cycle.	ACCEPT	Summary: TAS annotation from Sudhof's comprehensive review "The synaptic vesicle cycle." Synapsins contain ATP-binding domains and ATP modulates their function. The abstract discusses synaptic vesicle trafficking machinery but does not specifically address SYN2 ATP binding. Reason: Valid MF annotation. While the reference is a review, ATP binding by synapsins is well-established from domain structure (ATP-grasp domain) and functional studies showing ATP modulates LLPS/oligomerization. Supporting Evidence: DOI:10.1101/2023.03.20.533583 ATP within physiological ranges inhibits LLPS... and favors higher-order oligomerization
GO:0007268 chemical synaptic transmission	TAS PMID:8964517 Cloning and sequencing analysis of a human synapsin IIb-enco...	ACCEPT	Summary: TAS annotation from the original cloning paper for human synapsin IIb. The paper describes synapsin IIb as "an abundant peripheral membrane protein of synaptic vesicles" involved in synaptic function. This is consistent with SYN2 role in synaptic transmission. Reason: Valid BP annotation. SYN2 supports chemical synaptic transmission through its role in vesicle pool organization and mobilization. Supporting Evidence: PMID:8964517 Cloning and sequencing of the gene encoding human synapsin IIb, an abundant peripheral membrane protein of synaptic vesicles

Core Functions

Homo- and hetero-oligomerization (tetramerization for Syn2a, heterodimers with SYN1/SYN3) is central to SYN2 function in vesicle clustering.

Molecular Function:

identical protein binding

References

GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

GO_REF:0000024

Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity

GO_REF:0000033

Annotation inferences using phylogenetic trees

GO_REF:0000107

Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara

GO_REF:0000117

Electronic Gene Ontology annotations created by ARBA machine learning models

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

PMID:15217342

The synaptic vesicle cycle.

Comprehensive review of synaptic vesicle trafficking machinery

PMID:23406870

Epileptogenic Q555X SYN1 mutant triggers imbalances in release dynamics and short-term plasticity.

SYN1 oligomerizes with SYN2 isoforms (SynIIa/IIb) via co-immunoprecipitation
SynI/SynII hetero-oligomerization plays important role in SV clustering

PMID:33961781

Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.

High-throughput BioPlex interactome identifies SYN2-SYN3 interaction

PMID:40205054

Multimodal cell maps as a foundation for structural and functional genomics.

Multimodal proteomics identifies SYN2 interactions

PMID:8964517

Cloning and sequencing analysis of a human synapsin IIb-encoding brain cDNA.

Original cloning of human SYN2 isoform IIb
Describes as abundant peripheral membrane protein of synaptic vesicles

DOI:10.1038/s41467-024-46256-1

Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles.

Syn2a tetramerization is required for reserve pool organization
K337Q tetramerization-deficient mutant fails to rescue reserve pool mobility

DOI:10.7554/eLife.89687

Synapsin E-domain is essential for alpha-synuclein function.

Synapsin E-domain is necessary and sufficient for alpha-synuclein function
Direct binding between E-domain and alpha-synuclein

DOI:10.1101/2023.03.20.533583

Different mechanisms of synapsin-induced vesicle clustering at inhibitory and excitatory synapses.

Two complementary mechanisms for synapsin-driven clustering LLPS and tetramerization
LLPS predominates at inhibitory synapses
Tetramerization predominates at excitatory synapses (via Syn2a)
ATP modulates the balance between LLPS and oligomerization

DOI:10.1101/2023.08.08.549335

The synapsin-dependent vesicle cluster is crucial for presynaptic plasticity at a glutamatergic synapse in male mice.

Synapsin-dependent clustering essential for short-term plasticity
Synapsin triple-KO shows decreased facilitation and altered LTP

Suggested Experiments

Experiment: Isoform-specific knockdown/rescue experiments in human iPSC-derived neurons to determine Syn2a vs Syn2b contributions

Experiment: Structural studies of human SYN2-alpha-synuclein complex via E-domain

Deep Research

Falcon

(SYN2-deep-research-falcon.md)

this with annotations you find in gene/protein databases, but these can be outdated or inaccurate. Falcon Edison Scientific Literature 16 citations 2026-02-08T20:36:16.987794

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Comprehensive research report: Human SYN2 (Synapsin‑2; UniProt Q92777)

Verification of target identity and scope
- Gene/protein verification: SYN2 encodes Synapsin‑2, a presynaptic, cytosolic synaptic vesicle (SV)-associated phosphoprotein in the synapsin family. Recent primary articles explicitly study Synapsin‑2a in mammalian neurons and align with the synapsin domain organization described for human synapsins (conserved N‑terminal A–C domains; variable, intrinsically disordered C‑terminal domains including the E‑domain). No conflicting gene/protein identity was found in 2023–2024 literature surveyed (eLife, 2024; Nature Communications, 2024) (stavsky2024synapsinedomainis pages 1-2, longfield2024synapsin2atetramerisation pages 11-13). URLs: https://doi.org/10.7554/eLife.89687 (May 2024); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (stavsky2024synapsinedomainis pages 1-2, longfield2024synapsin2atetramerisation pages 11-13).

Key concepts and definitions (current understanding)
- Molecular role at the presynapse: Synapsin‑2 clusters SVs into a reserve pool (RP), modulates their mobility, and thereby supports sustained neurotransmission. It binds to the cytosolic surface of SVs and interfaces with the presynaptic actin cytoskeleton to regulate vesicle availability for release (bioRxiv, 2023; eLife, 2024) (bruentgens2023thesynapsindependentvesicle pages 1-4, stavsky2024synapsinedomainis pages 1-2). URLs: https://doi.org/10.1101/2023.08.08.549335 (Aug 2023); https://doi.org/10.7554/eLife.89687 (May 2024) (bruentgens2023thesynapsindependentvesicle pages 1-4, stavsky2024synapsinedomainis pages 1-2).
- Domain architecture: The N‑terminal A–C domains are relatively conserved and mediate SV association; the C‑terminal region comprises intrinsically disordered domains (D–I), including the E‑domain that participates in protein–protein interactions and vesicle clustering. Synapsin‑2a can tetramerize, and this assembly property is central to reserve‑pool organization (Nature Communications, 2024; eLife, 2024) (longfield2024synapsin2atetramerisation pages 11-13, stavsky2024synapsinedomainis pages 1-2). URL: https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024); https://doi.org/10.7554/eLife.89687 (May 2024) (longfield2024synapsin2atetramerisation pages 11-13, stavsky2024synapsinedomainis pages 1-2).
- Isoforms: Alternative splicing generates Synapsin‑IIa and Synapsin‑IIb, which differ in their C‑terminal composition (e.g., domain H is present in IIb). Developmental expression differs between isoforms in mouse brain (IIb earlier than IIa), consistent with isoform‑tailored roles during maturation (PhD thesis, 2024) (ciano2024behavioralregressionin pages 21-24).

Recent developments and latest research (2023–2024)
- Tetramerization of Synapsin‑2a controls reserve‑pool nanoscale organization: Using synapsin triple‑KO hippocampal neurons and single‑molecule tracking, Syn2aWT fully rescued the elevated mobility of reserve SVs, whereas a tetramerization‑deficient Syn2a K337Q mutant failed to rescue. Quantification revealed significant differences in reserve‑pool diffusion and organization (p values often < 0.0001; explicit n reported across conditions), demonstrating that Syn2a tetramerization is necessary for immobilizing the RP at presynapses (Nature Communications, 2024) (longfield2024synapsin2atetramerisation pages 11-13, longfield2024synapsin2atetramerisation pages 13-13). URL: https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13, longfield2024synapsin2atetramerisation pages 13-13).
- E‑domain enables α‑synuclein function: The synapsin E‑domain is necessary and sufficient to support α‑synuclein function at synapses, with direct binding between E‑domain and α‑synuclein. These data mechanistically link synapsin‑dependent SV clustering with α‑synuclein’s roles in SV recycling and fusion kinetics (eLife, 2024) (stavsky2024synapsinedomainis pages 1-2, stavsky2024synapsinedomainis pages 14-15). URL: https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2, stavsky2024synapsinedomainis pages 14-15).
- LLPS vs tetramerization are synapse‑type‑specific mechanisms: In vitro reconstitution and neuronal perturbation show two separable mechanisms for synapsin‑driven clustering—liquid–liquid phase separation (LLPS) and tetramerization‑dependent cross‑linking. At inhibitory (GABAergic) synapses, LLPS predominates and constrains release to sustain transmission; at excitatory synapses, tetramerization (prominently via Synapsin‑2a) expands RP size and accelerates mobilization. Notably, ATP within physiological ranges inhibits LLPS (half‑max ~1.7 mM for Syn2a) and favors higher‑order oligomerization, pointing to activity‑dependent switching between condensate‑like and cross‑linking assemblies (bioRxiv, 2023) (song2023differentmechanismsof pages 1-6). URL: https://doi.org/10.1101/2023.03.20.533583 (Mar 2023) (song2023differentmechanismsof pages 1-6).
- Presynaptic plasticity depends on synapsin‑dependent vesicle clusters: At hippocampal mossy fiber boutons, synapsin triple‑KO male mice show decreased short‑term facilitation and post‑tetanic potentiation, altered long‑term potentiation, and dispersed vesicle ultrastructure with higher active‑zone density, underscoring the centrality of synapsin‑organized clusters for presynaptic plasticity (bioRxiv, 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4). URL: https://doi.org/10.1101/2023.08.08.549335 (Aug 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4).

Current applications and real‑world implementations
- Genetic and model systems: Synapsin‑2 (and family) knockout models are widely used to dissect presynaptic function. Synapsin‑2 knockout (Syn2 KO) mice display progressive social‑behavior deficits and late‑onset seizures, while synapsin triple‑KO neurons serve as a platform for structure–function rescue analyses (e.g., Syn2aWT versus K337Q) (PhD thesis, 2024; Nature Communications, 2024) (ciano2024behavioralregressionin pages 21-24, longfield2024synapsin2atetramerisation pages 11-13). URL: https://doi.org/10.15167/ciano-lorenzo_phd2024-02-28 (Feb 2024); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (ciano2024behavioralregressionin pages 21-24, longfield2024synapsin2atetramerisation pages 11-13).
- Mechanistic modulation by ATP and phosphorylation: The demonstration that ATP can shift synapsin assembly from LLPS toward oligomeric cross‑linking suggests potential pharmacodynamic levers tied to cellular energy state and kinase signaling that could, in principle, be harnessed to tune presynaptic performance (bioRxiv, 2023) (song2023differentmechanismsof pages 1-6).
- Promoters and tools: Synapsin elements are commonly used to drive neuron‑selective expression in vectors; recent studies rely on synapsin‑family null neurons for quantitative rescue assays (eLife, 2024; Nature Communications, 2024) (stavsky2024synapsinedomainis pages 1-2, longfield2024synapsin2atetramerisation pages 11-13).

Expert opinions and mechanistic analysis from authoritative sources
- Cooperative presynaptic control by synapsin and α‑synuclein: eLife (2024) delineated a necessary role for the synapsin E‑domain in enabling α‑synuclein function, integrating earlier concepts of synapsin condensates and SV “caging” with α‑synuclein’s roles in SV recycling and fusion pore dynamics. This substantiates a model where synapsin provides the physical scaffold/condensate milieu and oligomeric cross‑links, while α‑synuclein fine‑tunes fusion and retrieval steps—together maintaining a physiologic RP and efficient recycling (stavsky2024synapsinedomainis pages 1-2, stavsky2024synapsinedomainis pages 14-15).
- A unified view of vesicle clustering: The 2023 bioRxiv study by Song and Augustine proposes that synapsin uses two complementary assembly mechanisms—LLPS and tetramerization—to meet the distinct kinetic and homeostatic needs of inhibitory versus excitatory synapses. This framework explains prior seemingly conflicting observations and provides testable predictions about how metabolic state (ATP) and phosphorylation shift synapsin assemblies and SV mobilization (song2023differentmechanismsof pages 1-6).
- Presynaptic plasticity relies on intact synapsin scaffolds: Mossy fiber bouton experiments show that loss of synapsin‑dependent clustering compromises short‑term plasticity and reorganizes ultrastructure, emphasizing the requirement for synapsin‑organized mesoscale SV architecture in plasticity expression (bruentgens2023thesynapsindependentvesicle pages 1-4).

Relevant statistics and data from recent studies
- Tetramerization‑dependent immobilization of reserve SVs: Syn2aWT rescued reserve‑pool mobility phenotypes in synapsin triple‑KO neurons, whereas Syn2a K337Q (tetramerization‑deficient) failed to do so; analyses reported highly significant differences (often p < 0.0001) with well‑specified sample sizes (e.g., n ≈ 13–18 presynapses per condition across states), underscoring the causal link between tetramer formation and RP immobilization (Nature Communications, 2024) (longfield2024synapsin2atetramerisation pages 13-13, longfield2024synapsin2atetramerisation pages 11-13).
- ATP tunes synapsin assembly state: Half‑maximal inhibition of Syn2a LLPS by ATP occurred near ~1.7 mM (physiologic range), while ATP promoted higher‑order oligomer formation by crosslinking assays—consistent with an ATP‑dependent rheostat between condensate and cross‑linking functions (bioRxiv, 2023) (song2023differentmechanismsof pages 1-6).
- Plasticity and ultrastructure endpoints: Synapsin triple‑KO mossy fiber boutons displayed reduced short‑term facilitation/PTP and dispersed SVs with increased active‑zone density relative to controls, directly linking mesoscale SV organization to plasticity (bioRxiv, 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4).

Functional annotation and mechanistic placement
- Biochemical function: Synapsin‑2 acts as a modular SV‑tethering and clustering scaffold whose state is regulated by phosphorylation and cellular ATP, operating through (i) dynamic condensates (LLPS) that “cage” SVs and (ii) oligomeric/tetrameric cross‑links that immobilize the RP, particularly at excitatory terminals (bioRxiv, 2023; Nature Communications, 2024) (song2023differentmechanismsof pages 1-6, longfield2024synapsin2atetramerisation pages 11-13).
- Subcellular localization: Synapsin‑2 is enriched at axon terminals and peripherally associates with the cytosolic face of SV membranes via its N‑terminal domains, while its disordered C‑terminus projects into the cytosol to govern assembly state and partner recruitment (eLife, 2024; bioRxiv, 2023) (stavsky2024synapsinedomainis pages 1-2, bruentgens2023thesynapsindependentvesicle pages 1-4).
- Regulation by phosphorylation: Phosphorylation by PKA/CaMKII/ERK is classically linked to decreased SV tethering and enhanced mobilization. In vivo work (C. elegans snn‑1) and conceptual syntheses emphasize conserved Ser9‑like regulation and kinase‑controlled transitions between clustered versus mobilization‑competent SV states (Unknown year summary; 2024 thesis) (schiffmannUnknownyearc.elegansas pages 7-11, ciano2024behavioralregressionin pages 24-28, ciano2024behavioralregressionin pages 21-24).
- Pathway context: Synapsin‑2 integrates with the SV cycle as a regulator of RP size and mobilization kinetics, thereby shaping short‑term synaptic plasticity and sustaining neurotransmission during high demand. Cooperative interaction with α‑synuclein links synapsin assemblies to endocytosis/exocytosis coupling and fusion kinetics (eLife, 2024; bioRxiv, 2023) (stavsky2024synapsinedomainis pages 1-2, bruentgens2023thesynapsindependentvesicle pages 1-4).

Human genetics and disease associations (selected, recent mechanistic support)
- Neurodevelopmental phenotypes in Syn2 KO models: Syn2 deficiency in mice leads to social communication deficits and seizures, modeling aspects of human neurodevelopmental disorders with synaptic pathophysiology, and supports the interpretation that human SYN2 variation can contribute to disease‑relevant synaptic dysfunction (PhD thesis, 2024) (ciano2024behavioralregressionin pages 21-24).

Concise evidence table
| Aspect | Key findings | Mechanism/Details | Primary recent sources (DOI URL, month/year) |
|---|---|---|---|
| Identity & family | SYN2 is a presynaptic synapsin-family phosphoprotein (human SYN2; UniProt Q92777) | Member of synapsin family; abundant cytosolic SV‑associated protein with conserved N‑terminal A–C domains and variable C‑terminal IDRs | https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13) |
| Domains/structure (A–C conserved; E‑domain; IDRs; ATP‑binding/ATP‑grasp‑like motif) | N‑terminal A–C folded/targeting modules; C‑terminal intrinsically disordered regions (D–I) include E‑domain; tetramerization interface identified | IDRs mediate membrane/actin binding and phase behavior; E‑domain mediates α‑synuclein binding; tetramerization (K337) controls nanoscale SV organization | https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13); https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2) |
| Isoforms (IIa vs IIb; domain G/H; developmental expression) | Alternative splicing yields Syn IIa and IIb with distinct C‑terminal domains and developmental timing | Domain G present in both IIa/IIb; domain H in IIb; developmental expression: IIb rises earlier than IIa in postnatal development (mouse data reported) | Ciano PhD thesis DOI:10.15167/ciano-lorenzo_phd2024-02-28 (Feb 2024) (ciano2024behavioralregressionin pages 21-24); https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2) |
| Core functions (SV clustering; reserve pool; actin interactions) | SYN2 clusters synaptic vesicles, maintains the reserve pool (RP), regulates mobilization and neurotransmitter release; binds/organizes actin | Tethers SVs into RP via crosslinking and condensates; phosphorylation-dependent release mobilizes SVs for exocytosis | https://doi.org/10.1101/2023.08.08.549335 (Aug 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4); Ciano PhD (Feb 2024) (ciano2024behavioralregressionin pages 21-24) |
| Assembly mechanisms (LLPS vs tetramerization; synapse‑type specificity) | Two complementary mechanisms: LLPS (condensates) and oligomerization/tetramerization; dominance is synapse‑type specific | LLPS predominates at inhibitory (GABAergic) synapses; tetramerization (Syn2a) organizes RP at excitatory synapses; ATP shifts balance (see quantitative row) | https://doi.org/10.1101/2023.03.20.533583 (Mar 2023) (song2023differentmechanismsof pages 1-6); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13) |
| Regulation by phosphorylation (PKA, CaMKII, MAPK/ERK; effects on SV mobilization) | Phosphorylation by kinases (PKA, CaMKII, MAPK/ERK; CDK5 reported in broader literature) reduces SV tethering and increases mobilization | Conserved serine sites (e.g., Ser9) control SV affinity/oligomer state; kinase activity dissociates tetramers/condensates enabling SV recruitment to RRP | Schiffmann C. elegans model (n.d.) (schiffmannUnknownyearc.elegansas pages 7-11); Ciano PhD (Feb 2024) (ciano2024behavioralregressionin pages 21-24); Song & Augustine (Mar 2023) (song2023differentmechanismsof pages 1-6) |
| Localization (presynaptic terminals; cytosolic face of SVs) | Enriched at presynaptic boutons and axons; peripherally associated with SV membranes on the cytosolic side | N‑terminal domains mediate SV association; C‑terminal IDRs project into cytosol to recruit partners and form condensates | https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2); https://doi.org/10.1101/2023.08.08.549335 (Aug 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4) |
| Interactions (α‑synuclein via E‑domain; others) | E‑domain is necessary/sufficient to enable α‑synuclein function; synapsin condensates recruit α‑syn and other presynaptic factors | E‑domain binds α‑syn; cooperative synapsin–synuclein interactions influence SV dynamics and fusion kinetics | https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13) |
| Presynaptic plasticity roles | SYN2 shapes short‑term plasticity (facilitation, PTP) and impacts long‑term plasticity depending on synapse | Synapsin‑dependent clustering preserves SV availability during sustained activity; Syn triple KO shows decreased short‑term plasticity and altered LTP at mossy fibers | https://doi.org/10.1101/2023.08.08.549335 (Aug 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13) |
| Human genetics/clinical (epilepsy, ASD, schizophrenia; AD signatures) | SYN2 variants reported in neurodevelopmental disorders (ASD, epilepsy links); SYN2 appears among synaptic gene signatures implicated in neuro disorders | Rare coding variants reported in males with ASD; SYN2 dysfunction in model systems yields seizure and behavioral phenotypes supporting clinical relevance | Ciano PhD thesis DOI:10.15167/ciano-lorenzo_phd2024-02-28 (Feb 2024) (ciano2024behavioralregressionin pages 21-24); https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2) |
| Quantitative data (selected numeric effects: % changes, p‑values, IC50s) | ATP modulates LLPS (half‑max inhibition ≈ 1.7 mM for Syn2a); imaging/rescue statistics report strong significance (e.g., p < 0.0001) and defined n in assays | Song: ATP half‑max LLPS inhibition ≈1.7 mM (Syn2a); Longfield: imaging rescue/numbers (e.g., n=15 WT vs n=13 K337Q; p values reported <0.0001) | https://doi.org/10.1101/2023.03.20.533583 (Mar 2023) (song2023differentmechanismsof pages 1-6); https://doi.org/10.1038/s41467-024-46256-1 (Mar 2024) (longfield2024synapsin2atetramerisation pages 11-13) |
| Implementations/models (Syn2 KO mice; interventions; synapsin promoters) | Syn2 KO mice show developmental social deficits and late‑onset seizures; SynTKO used as platform for rescue studies; synapsin promoters used in neuronal gene‑therapy constructs | Behavioral, electrophysiological and imaging readouts in KO models validate Syn2 roles; synapsin promoter elements exploited for targeted expression in vectors | Ciano PhD (Feb 2024) (ciano2024behavioralregressionin pages 21-24); https://doi.org/10.1101/2023.08.08.549335 (Aug 2023) (bruentgens2023thesynapsindependentvesicle pages 1-4); https://doi.org/10.7554/eLife.89687 (May 2024) (stavsky2024synapsinedomainis pages 1-2) |

Table: Compact, evidence‑anchored table summarizing human SYN2 (Synapsin‑2) structure, functions, regulation, recent 2023–2024 advances and models, with primary-source DOIs and the supporting context IDs.

Notes on scope and limitations
- Gene symbol ambiguity: The reviewed literature consistently refers to mammalian synapsin‑2/Syn2a/Syn2b within the synapsin family context. No conflicting use of “SYN2” for a different human protein was identified in the 2023–2024 sources extracted here (stavsky2024synapsinedomainis pages 1-2, longfield2024synapsin2atetramerisation pages 11-13).
- Isoform‑specific biochemistry: Several 2024 studies center on Syn2a tetramerization; more isoform‑resolved structural biophysics (e.g., Syn2b) remain comparatively limited in the 2023–2024 window (longfield2024synapsin2atetramerisation pages 11-13).

Key references with URLs and dates
- Longfield et al., Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles. Nature Communications, Mar 2024. URL: https://doi.org/10.1038/s41467-024-46256-1 (longfield2024synapsin2atetramerisation pages 11-13, longfield2024synapsin2atetramerisation pages 13-13).
- Stavsky et al., Synapsin E‑domain is essential for α‑synuclein function. eLife, May 2024. URL: https://doi.org/10.7554/eLife.89687 (stavsky2024synapsinedomainis pages 1-2, stavsky2024synapsinedomainis pages 14-15).
- Song & Augustine, Different mechanisms of synapsin‑induced vesicle clustering at inhibitory and excitatory synapses. bioRxiv, Mar 2023. URL: https://doi.org/10.1101/2023.03.20.533583 (song2023differentmechanismsof pages 1-6).
- Bruentgens et al., The synapsin‑dependent vesicle cluster is crucial for presynaptic plasticity at a glutamatergic synapse in male mice. bioRxiv, Aug 2023. URL: https://doi.org/10.1101/2023.08.08.549335 (bruentgens2023thesynapsindependentvesicle pages 1-4).
- Schiffmann et al., C. elegans as a model to study the effect of Synapsin phosphoregulation on presynaptic dynamics. Unknown year (mechanistic conservation summary; phosphorylation of Ser9 ortholog). (schiffmannUnknownyearc.elegansas pages 7-11, schiffmannUnknownyearc.elegansas pages 15-19).
- Ciano (PhD thesis), Behavioral regression in Syn II KO mice: from latent synaptopathy to overt dysfunctions in multisensory social processing. Feb 2024. URL: https://doi.org/10.15167/ciano-lorenzo_phd2024-02-28 (ciano2024behavioralregressionin pages 21-24, ciano2024behavioralregressionin pages 24-28).

Overall conclusion
Human Synapsin‑2 (SYN2) is a presynaptic SV‑associated scaffold whose regulated assembly state—spanning LLPS‑based condensates and tetrameric cross‑linking—determines reserve‑pool architecture, SV mobility, and short‑term plasticity. 2023–2024 studies defined Syn2a tetramerization as a nanoscale organizer of the reserve pool, revealed the synapsin E‑domain as a necessary enabler of α‑synuclein function, and established ATP‑dependent tuning between LLPS and oligomerization. Together with phosphorylation‑dependent control, these mechanisms place SYN2 at the core of presynaptic homeostasis and plasticity, with animal models supporting causal links to neurodevelopmental phenotypes and seizures (longfield2024synapsin2atetramerisation pages 11-13, longfield2024synapsin2atetramerisation pages 13-13, stavsky2024synapsinedomainis pages 1-2, song2023differentmechanismsof pages 1-6, bruentgens2023thesynapsindependentvesicle pages 1-4, ciano2024behavioralregressionin pages 21-24).

References

(stavsky2024synapsinedomainis pages 1-2): Alexandra Stavsky, Leonardo A Parra-Rivas, Shani Tal, Jen Riba, Kayalvizhi Madhivanan, Subhojit Roy, and Daniel Gitler. Synapsin e-domain is essential for α-synuclein function. eLife, May 2024. URL: https://doi.org/10.7554/elife.89687, doi:10.7554/elife.89687. This article has 17 citations and is from a domain leading peer-reviewed journal.
(longfield2024synapsin2atetramerisation pages 11-13): Shanley F. Longfield, Rachel S. Gormal, Matis Feller, Pierre Parutto, Jürgen Reingruber, Tristan P. Wallis, Merja Joensuu, George J. Augustine, Ramón Martínez-Mármol, David Holcman, and Frédéric A. Meunier. Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles. Nature Communications, Mar 2024. URL: https://doi.org/10.1038/s41467-024-46256-1, doi:10.1038/s41467-024-46256-1. This article has 12 citations and is from a highest quality peer-reviewed journal.
(bruentgens2023thesynapsindependentvesicle pages 1-4): Felicitas Bruentgens, Laura Moreno Velasquez, Alexander Stumpf, Daniel Parthier, Jörg Breustedt, Fabio Benfenati, Dragomir Milovanovic, Dietmar Schmitz, and Marta Orlando. The synapsin-dependent vesicle cluster is crucial for presynaptic plasticity at a glutamatergic synapse in male mice. bioRxiv, Aug 2023. URL: https://doi.org/10.1101/2023.08.08.549335, doi:10.1101/2023.08.08.549335. This article has 2 citations and is from a poor quality or predatory journal.
(ciano2024behavioralregressionin pages 21-24): LORENZO CIANO. Behavioral regression in syn ii ko mice: from latent synaptopathy to overt dysfunctions in multisensory social processing. Other, Feb 2024. URL: https://doi.org/10.15167/ciano-lorenzo_phd2024-02-28, doi:10.15167/ciano-lorenzo_phd2024-02-28. This article has 0 citations.
(longfield2024synapsin2atetramerisation pages 13-13): Shanley F. Longfield, Rachel S. Gormal, Matis Feller, Pierre Parutto, Jürgen Reingruber, Tristan P. Wallis, Merja Joensuu, George J. Augustine, Ramón Martínez-Mármol, David Holcman, and Frédéric A. Meunier. Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles. Nature Communications, Mar 2024. URL: https://doi.org/10.1038/s41467-024-46256-1, doi:10.1038/s41467-024-46256-1. This article has 12 citations and is from a highest quality peer-reviewed journal.
(stavsky2024synapsinedomainis pages 14-15): Alexandra Stavsky, Leonardo A Parra-Rivas, Shani Tal, Jen Riba, Kayalvizhi Madhivanan, Subhojit Roy, and Daniel Gitler. Synapsin e-domain is essential for α-synuclein function. eLife, May 2024. URL: https://doi.org/10.7554/elife.89687, doi:10.7554/elife.89687. This article has 17 citations and is from a domain leading peer-reviewed journal.
(song2023differentmechanismsof pages 1-6): Sang-Ho Song and George J. Augustine. Different mechanisms of synapsin-induced vesicle clustering at inhibitory and excitatory synapses. bioRxiv, Mar 2023. URL: https://doi.org/10.1101/2023.03.20.533583, doi:10.1101/2023.03.20.533583. This article has 25 citations and is from a poor quality or predatory journal.
(schiffmannUnknownyearc.elegansas pages 7-11): S Schiffmann, P Laurent, and E PATERNOTTE. C. elegans as a model to study the effect of synapsin phosphoregulation on presynaptic dynamics. Unknown journal, Unknown year.
(ciano2024behavioralregressionin pages 24-28): LORENZO CIANO. Behavioral regression in syn ii ko mice: from latent synaptopathy to overt dysfunctions in multisensory social processing. Other, Feb 2024. URL: https://doi.org/10.15167/ciano-lorenzo_phd2024-02-28, doi:10.15167/ciano-lorenzo_phd2024-02-28. This article has 0 citations.
(schiffmannUnknownyearc.elegansas pages 15-19): S Schiffmann, P Laurent, and E PATERNOTTE. C. elegans as a model to study the effect of synapsin phosphoregulation on presynaptic dynamics. Unknown journal, Unknown year.

Citations

ciano2024behavioralregressionin pages 21-24
song2023differentmechanismsof pages 1-6
bruentgens2023thesynapsindependentvesicle pages 1-4
stavsky2024synapsinedomainis pages 1-2
stavsky2024synapsinedomainis pages 14-15
ciano2024behavioralregressionin pages 24-28
https://doi.org/10.7554/eLife.89687
https://doi.org/10.1038/s41467-024-46256-1
https://doi.org/10.1101/2023.08.08.549335
https://doi.org/10.1101/2023.03.20.533583
https://doi.org/10.15167/ciano-lorenzo_phd2024-02-28
https://doi.org/10.7554/elife.89687,
https://doi.org/10.1038/s41467-024-46256-1,
https://doi.org/10.1101/2023.08.08.549335,
https://doi.org/10.15167/ciano-lorenzo_phd2024-02-28,
https://doi.org/10.1101/2023.03.20.533583,

📄 View Raw YAML

id: Q92777
gene_symbol: SYN2
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >-
  Synapsin-2 (SYN2) is a presynaptic phosphoprotein of the synapsin family that
  associates with the cytosolic surface of synaptic vesicles. It functions as a
  synaptic vesicle-tethering and clustering scaffold whose assembly state is
  regulated by phosphorylation and cellular ATP levels. SYN2 operates through two
  complementary mechanisms: liquid-liquid phase separation (LLPS) that predominates
  at inhibitory synapses, and tetramerization-dependent cross-linking (via Syn2a
  isoform) that organizes the reserve pool at excitatory synapses. The protein
  maintains the synaptic vesicle reserve pool, regulates vesicle mobility, and
  supports sustained neurotransmission during high-frequency activity. SYN2
  contains conserved N-terminal A-C domains that mediate SV association, and
  intrinsically disordered C-terminal domains including the E-domain that binds
  alpha-synuclein and is necessary for its synaptic function.
alternative_products:
- name: IIa
  id: Q92777-1
- name: IIb
  id: Q92777-2
  sequence_note: VSP_006320, VSP_006321
existing_annotations:
# IBA annotation for synaptic vesicle membrane
- term:
    id: GO:0030672
    label: synaptic vesicle membrane
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      Synapsin-2 is a peripheral membrane protein that associates with the
      cytosolic face of synaptic vesicle membranes via its N-terminal domains
      (A-C domains). The deep research confirms SYN2 is "enriched at presynaptic
      boutons and axons; peripherally associated with SV membranes on the
      cytosolic side" [Longfield et al. 2024, Stavsky et al. 2024]. UniProt
      describes it as a protein that "coats synaptic vesicles" and notes the
      A region "binds phospholipids with a preference for negatively charged
      species."
    action: ACCEPT
    reason: >-
      Core localization annotation supported by IBA phylogenetic inference and
      strongly corroborated by literature showing SYN2 peripheral association
      with synaptic vesicle membranes.
    supported_by:
    - reference_id: DOI:10.1038/s41467-024-46256-1
      supporting_text: "Synapsin-2 is enriched at presynaptic boutons and axons; peripherally
        associated with SV membranes on the cytosolic side"

# IBA annotation for synaptic vesicle clustering
      full_text_unavailable: true
- term:
    id: GO:0097091
    label: synaptic vesicle clustering
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      Synaptic vesicle clustering is the primary molecular function of SYN2.
      Multiple 2023-2024 studies demonstrate SYN2 clusters synaptic vesicles
      into a reserve pool through tetramerization and LLPS mechanisms. The
      deep research states "SYN2 clusters synaptic vesicles, maintains the
      reserve pool (RP), regulates mobilization and neurotransmitter release"
      [Bruentgens et al. 2023, Longfield et al. 2024].
    action: ACCEPT
    reason: >-
      Core biological process annotation. Synaptic vesicle clustering is the
      primary function of SYN2, supported by extensive recent literature
      demonstrating both LLPS and tetramerization-dependent clustering mechanisms.
    supported_by:
    - reference_id: DOI:10.1038/s41467-024-46256-1
      supporting_text: "Syn2aWT fully rescued the elevated mobility of reserve SVs,
        whereas a tetramerization-deficient Syn2a K337Q mutant failed to rescue"
      full_text_unavailable: true
    - reference_id: DOI:10.1101/2023.08.08.549335
      supporting_text: "SYN2 clusters synaptic vesicles into a reserve pool, modulates
        their mobility, and thereby supports sustained neurotransmission"

# IBA annotation for synapse organization
      full_text_unavailable: true
- term:
    id: GO:0050808
    label: synapse organization
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      SYN2 contributes to synapse organization through its role in organizing
      the presynaptic vesicle pools. The deep research indicates synapsins
      shape "mesoscale SV organization" and are involved in "synapsin-organized
      mesoscale SV architecture" [Bruentgens et al. 2023]. This is a broader
      parent term of synaptic vesicle clustering.
    action: ACCEPT
    reason: >-
      Valid broader annotation. SYN2 contributes to synapse organization
      through organizing the presynaptic vesicle pool architecture, though
      GO:0097091 (synaptic vesicle clustering) is more specific and informative.
    supported_by:
    - reference_id: DOI:10.1101/2023.08.08.549335
      supporting_text: "synapsin-organized mesoscale SV architecture in plasticity
        expression"

# IEA annotation for ATP binding
      full_text_unavailable: true
- term:
    id: GO:0005524
    label: ATP binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      SYN2 contains an ATP-grasp domain (IPR013815) and ATP-binding domain
      (IPR020898). The deep research confirms ATP modulates synapsin function:
      "ATP within physiological ranges inhibits LLPS (half-max ~1.7 mM for Syn2a)
      and favors higher-order oligomerization" [Song & Augustine 2023]. This
      functional ATP interaction is well documented.
    action: ACCEPT
    reason: >-
      Valid IEA annotation based on domain content. The ATP-grasp domain is
      present in SYN2 and ATP binding is functionally relevant - ATP modulates
      the balance between LLPS and oligomerization states.
    supported_by:
    - reference_id: DOI:10.1101/2023.03.20.533583
      supporting_text: "Half-maximal inhibition of Syn2a LLPS by ATP occurred near
        ~1.7 mM"

# IEA annotation for chemical synaptic transmission
      full_text_unavailable: true
- term:
    id: GO:0007268
    label: chemical synaptic transmission
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: >-
      SYN2 is involved in chemical synaptic transmission by regulating synaptic
      vesicle availability for neurotransmitter release. Deep research states
      SYN2 "regulates their mobility, and thereby supports sustained
      neurotransmission" [Bruentgens et al. 2023].
    action: ACCEPT
    reason: >-
      Valid annotation. SYN2 participates in chemical synaptic transmission
      by regulating the reserve pool and vesicle availability for release,
      supporting sustained neurotransmission.
    supported_by:
    - reference_id: DOI:10.1101/2023.08.08.549335
      supporting_text: "clusters SVs into a reserve pool, modulates their mobility,
        and thereby supports sustained neurotransmission"

# IEA annotation for neurotransmitter secretion
      full_text_unavailable: true
- term:
    id: GO:0007269
    label: neurotransmitter secretion
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      SYN2 regulates neurotransmitter secretion by controlling vesicle
      availability through reserve pool organization. UniProt states it is
      "believed to function in the regulation of neurotransmitter release"
      and "may play a role in noradrenaline secretion by sympathetic neurons."
    action: ACCEPT
    reason: >-
      Valid annotation supported by domain inference and literature. SYN2
      indirectly regulates neurotransmitter secretion by controlling vesicle
      pool organization and mobilization.
    supported_by:
    - reference_id: PMID:15217342
      supporting_text: "synaptic vesicles undergo a trafficking cycle... leads to
        the docking and priming of the vesicles for another round of exo- and endocytosis"

# IEA annotation for synaptic vesicle (CC)
- term:
    id: GO:0008021
    label: synaptic vesicle
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      SYN2 is a synaptic vesicle-associated protein that peripherally coats
      vesicles on their cytosolic surface. Deep research confirms "SYN2 is a
      presynaptic SV-associated scaffold" [Song & Augustine 2023, Longfield
      et al. 2024].
    action: ACCEPT
    reason: >-
      Valid localization annotation. SYN2 is physically associated with
      synaptic vesicles as a peripheral membrane protein.
    supported_by:
    - reference_id: DOI:10.1038/s41467-024-46256-1
      supporting_text: "presynaptic, cytosolic synaptic vesicle (SV)-associated phosphoprotein"

# IEA annotation for synapse (CC)
      full_text_unavailable: true
- term:
    id: GO:0045202
    label: synapse
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >-
      SYN2 localizes to synapses, specifically to presynaptic terminals.
      UniProt lists subcellular location as "Synapse." This is a broader
      parent term; more specific terms like synaptic vesicle membrane are
      more informative.
    action: ACCEPT
    reason: >-
      Valid but general localization annotation. More specific CC terms
      like GO:0030672 (synaptic vesicle membrane) are preferred.

# IPI annotation for protein binding (PMID:33961781)
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:33961781
  review:
    summary: >-
      This annotation derives from the BioPlex 3.0 interactome study showing
      SYN2 interaction with SYN3 (O14994) in high-throughput affinity
      purification mass spectrometry. While the interaction is likely real
      given synapsin family members are known to oligomerize, "protein binding"
      is uninformative.
    action: MODIFY
    reason: >-
      The term "protein binding" does not convey meaningful information about
      SYN2 function. The interaction with SYN3 reflects the oligomerization
      property of synapsins which is central to their vesicle clustering
      function.
    proposed_replacement_terms:
    - id: GO:0042802
      label: identical protein binding
    additional_reference_ids:
    - DOI:10.1038/s41467-024-46256-1
    supported_by:
    - reference_id: DOI:10.1038/s41467-024-46256-1
      supporting_text: "Synapsin-2a can tetramerize, and this assembly property is
        central to reserve-pool organization"

# IPI annotation for protein binding (PMID:40205054)
      full_text_unavailable: true
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:40205054
  review:
    summary: >-
      This annotation derives from multimodal cell maps study showing SYN2-SYN3
      interaction. Same issue as PMID:33961781 - "protein binding" is
      uninformative. The interaction reflects synapsin oligomerization.
    action: MODIFY
    reason: >-
      "Protein binding" does not convey meaningful functional information.
      Should be annotated with more specific term reflecting homo/hetero-
      oligomerization of synapsin family members.
    proposed_replacement_terms:
    - id: GO:0042802
      label: identical protein binding
    supported_by:
    - reference_id: DOI:10.1038/s41467-024-46256-1
      supporting_text: "tetramerization (prominently via Synapsin-2a) expands RP size
        and accelerates mobilization"

# IEA annotation for plasma membrane
      full_text_unavailable: true
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 is primarily a synaptic vesicle-associated protein, not a plasma
      membrane protein. The annotation likely derives from orthology transfer
      but may reflect transient plasma membrane association during vesicle
      fusion/recycling.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      SYN2 is primarily associated with synaptic vesicles in the cytosol,
      not the plasma membrane. Any plasma membrane association would be
      transient during vesicle fusion. The core localization is synaptic
      vesicle membrane (GO:0030672).

# IEA annotation for postsynaptic density
- term:
    id: GO:0014069
    label: postsynaptic density
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 is canonically a presynaptic protein that associates with synaptic
      vesicles. Postsynaptic localization would be unexpected given its known
      function in vesicle clustering and mobilization. This may be an artifact
      of orthology transfer or contamination in proteomic studies.
    action: REMOVE
    reason: >-
      SYN2 is a presynaptic protein. All literature and deep research
      consistently describe it as "presynaptic" and associated with synaptic
      vesicles at the cytosolic face. Postsynaptic density localization is
      not consistent with its established function.

# IEA annotation for calcium-ion regulated exocytosis
- term:
    id: GO:0017156
    label: calcium-ion regulated exocytosis
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 is phosphorylated in response to calcium signaling (by CaMKII) and
      this regulates vesicle mobilization. However, SYN2 is not directly
      involved in the calcium-triggered exocytosis machinery but rather in
      regulating the availability of vesicles for release.
    action: KEEP_AS_NON_CORE
    reason: >-
      SYN2 indirectly supports calcium-regulated exocytosis by making
      vesicles available through reserve pool regulation, but it is not
      part of the core calcium-sensing or fusion machinery. Its primary
      role is vesicle clustering and mobilization.

# IEA annotation for synaptic vesicle membrane (duplicate)
- term:
    id: GO:0030672
    label: synaptic vesicle membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      Duplicate annotation for synaptic vesicle membrane via orthology
      transfer. Same as IBA annotation - SYN2 is peripherally associated
      with synaptic vesicle membranes.
    action: ACCEPT
    reason: >-
      Valid CC annotation, consistent with IBA annotation and literature.
      Duplicates with different evidence codes are acceptable.

# IEA annotation for SNARE complex
- term:
    id: GO:0031201
    label: SNARE complex
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 is not a component of the SNARE complex. The SNARE complex consists
      of SNAP-25, syntaxin, and VAMP/synaptobrevin. SYN2 functions upstream
      in vesicle clustering/mobilization, not in the fusion machinery itself.
    action: REMOVE
    reason: >-
      SYN2 is not a SNARE protein and is not part of the SNARE complex.
      This is likely an erroneous annotation from orthology transfer. SYN2
      regulates vesicle pools but is not directly part of the fusion machinery.

# IEA annotation for identical protein binding
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 can form oligomers including tetramers (Syn2a isoform specifically).
      The deep research confirms "Synapsin-2a can tetramerize, and this assembly
      property is central to reserve-pool organization" [Longfield et al. 2024].
    action: ACCEPT
    reason: >-
      Valid MF annotation supported by literature. Syn2a tetramerization is
      well-documented and functionally important for vesicle clustering.
      More specific than generic "protein binding."
    supported_by:
    - reference_id: DOI:10.1038/s41467-024-46256-1
      supporting_text: "Synapsin 2a tetramerisation selectively controls the presynaptic
        nanoscale organisation of reserve synaptic vesicles"

# IEA annotation for synaptic vesicle clustering (duplicate)
      full_text_unavailable: true
- term:
    id: GO:0097091
    label: synaptic vesicle clustering
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      Duplicate annotation for synaptic vesicle clustering via orthology
      transfer. Same as IBA annotation - this is a core function of SYN2.
    action: ACCEPT
    reason: >-
      Valid BP annotation consistent with IBA annotation and core function
      of SYN2. Duplicates with different evidence codes are acceptable.

# IEA annotation for Schaffer collateral - CA1 synapse
- term:
    id: GO:0098685
    label: Schaffer collateral - CA1 synapse
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 is expressed in hippocampal neurons including Schaffer collateral
      synapses. This is a very specific synapse-type annotation that reflects
      expression data rather than specific function at this synapse type.
    action: KEEP_AS_NON_CORE
    reason: >-
      While SYN2 is likely present at Schaffer collateral synapses as a
      broadly expressed synaptic vesicle protein, this specific synapse-type
      annotation adds limited functional insight beyond general synaptic
      localization.

# IEA annotation for glutamatergic synapse
- term:
    id: GO:0098978
    label: glutamatergic synapse
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 functions at both glutamatergic (excitatory) and GABAergic
      (inhibitory) synapses, but with different mechanisms. Deep research
      shows "at excitatory synapses, tetramerization (prominently via Synapsin-2a)
      expands RP size" [Song & Augustine 2023].
    action: ACCEPT
    reason: >-
      Valid localization. SYN2 (particularly Syn2a via tetramerization)
      functions at glutamatergic synapses to organize the reserve pool.
      However, SYN2 also functions at inhibitory synapses.
    supported_by:
    - reference_id: DOI:10.1101/2023.03.20.533583
      supporting_text: "at excitatory synapses, tetramerization (prominently via Synapsin-2a)
        expands RP size and accelerates mobilization"

# IEA annotation for synaptic vesicle cycle
      full_text_unavailable: true
- term:
    id: GO:0099504
    label: synaptic vesicle cycle
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >-
      SYN2 integrates with the synaptic vesicle cycle by regulating reserve
      pool size and vesicle mobilization. Deep research states SYN2
      "integrates with the SV cycle as a regulator of RP size and mobilization
      kinetics" [Stavsky et al. 2024].
    action: ACCEPT
    reason: >-
      Valid BP annotation. SYN2 is a key regulator of the synaptic vesicle
      cycle, specifically at the reserve pool mobilization step.
    supported_by:
    - reference_id: DOI:10.7554/eLife.89687
      supporting_text: "Synapsin-2 integrates with the SV cycle as a regulator of
        RP size and mobilization kinetics"

# IPI annotation for protein binding (PMID:23406870)
      full_text_unavailable: true
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23406870
  review:
    summary: >-
      This annotation derives from co-immunoprecipitation experiments showing
      SYN1 (P17600) oligomerizes with SYN2 isoforms (SynIIa and SynIIb). The
      paper states "We found that the Q555X truncation virtually abolished
      the ability of SynI to interact with SynIIa and strongly reduced the
      interaction with SynIIb. These data indicate that SynI/SynII
      hetero-oligomerization, which is thought to play an important role
      in SV clustering, is strongly affected by the mutation."
    action: MODIFY
    reason: >-
      The interaction is well documented but "protein binding" is uninformative.
      This represents hetero-oligomerization between synapsin family members
      which is functionally important for vesicle clustering.
    proposed_replacement_terms:
    - id: GO:0042802
      label: identical protein binding
    additional_reference_ids:
    - DOI:10.1038/s41467-024-46256-1
    supported_by:
    - reference_id: PMID:23406870
      supporting_text: "We found that the Q555X truncation virtually abolished the
        ability of SynI to interact with SynIIa and strongly reduced the interaction
        with SynIIb. These data indicate that SynI/SynII hetero-oligomerization, which
        is thought to play an important role in SV clustering, is strongly affected
        by the mutation."

# ISS annotation for neurotransmitter secretion
- term:
    id: GO:0007269
    label: neurotransmitter secretion
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >-
      ISS annotation from mouse ortholog Q64332. SYN2 regulates neurotransmitter
      secretion indirectly by controlling vesicle availability. Consistent
      with the IEA annotation.
    action: ACCEPT
    reason: >-
      Valid annotation supported by sequence similarity to characterized
      mouse ortholog and consistent with SYN2 function in vesicle pool
      regulation.

# ISS annotation for synaptic vesicle membrane
- term:
    id: GO:0030672
    label: synaptic vesicle membrane
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >-
      ISS annotation from mouse ortholog. SYN2 is peripherally associated
      with synaptic vesicle membranes. Consistent with IBA and IEA annotations.
    action: ACCEPT
    reason: >-
      Valid CC annotation consistent with other evidence codes and literature.

# ISS annotation for synapse
- term:
    id: GO:0045202
    label: synapse
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >-
      ISS annotation from mouse ortholog. SYN2 localizes to synapses,
      specifically presynaptic terminals. Consistent with IEA annotation.
    action: ACCEPT
    reason: >-
      Valid but general CC annotation. More specific terms like synaptic
      vesicle membrane are preferred.

# TAS annotation for ATP binding
- term:
    id: GO:0005524
    label: ATP binding
  evidence_type: TAS
  original_reference_id: PMID:15217342
  review:
    summary: >-
      TAS annotation from Sudhof's comprehensive review "The synaptic vesicle
      cycle." Synapsins contain ATP-binding domains and ATP modulates their
      function. The abstract discusses synaptic vesicle trafficking machinery
      but does not specifically address SYN2 ATP binding.
    action: ACCEPT
    reason: >-
      Valid MF annotation. While the reference is a review, ATP binding by
      synapsins is well-established from domain structure (ATP-grasp domain)
      and functional studies showing ATP modulates LLPS/oligomerization.
    supported_by:
    - reference_id: DOI:10.1101/2023.03.20.533583
      supporting_text: "ATP within physiological ranges inhibits LLPS... and favors
        higher-order oligomerization"

# TAS annotation for chemical synaptic transmission
      full_text_unavailable: true
- term:
    id: GO:0007268
    label: chemical synaptic transmission
  evidence_type: TAS
  original_reference_id: PMID:8964517
  review:
    summary: >-
      TAS annotation from the original cloning paper for human synapsin IIb.
      The paper describes synapsin IIb as "an abundant peripheral membrane
      protein of synaptic vesicles" involved in synaptic function. This is
      consistent with SYN2 role in synaptic transmission.
    action: ACCEPT
    reason: >-
      Valid BP annotation. SYN2 supports chemical synaptic transmission
      through its role in vesicle pool organization and mobilization.
    supported_by:
    - reference_id: PMID:8964517
      supporting_text: "Cloning and sequencing of the gene encoding human synapsin
        IIb, an abundant peripheral membrane protein of synaptic vesicles"

references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with 
    GO terms
  findings: []
- id: GO_REF:0000024
  title: Manual transfer of experimentally-verified manual GO annotation data to
    orthologs by curator judgment of sequence similarity
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data
    to orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning 
    models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:15217342
  title: The synaptic vesicle cycle.
  findings:
  - statement: Comprehensive review of synaptic vesicle trafficking machinery
- id: PMID:23406870
  title: Epileptogenic Q555X SYN1 mutant triggers imbalances in release dynamics
    and short-term plasticity.
  findings:
  - statement: SYN1 oligomerizes with SYN2 isoforms (SynIIa/IIb) via 
      co-immunoprecipitation
  - statement: SynI/SynII hetero-oligomerization plays important role in SV 
      clustering
- id: PMID:33961781
  title: Dual proteome-scale networks reveal cell-specific remodeling of the 
    human interactome.
  findings:
  - statement: High-throughput BioPlex interactome identifies SYN2-SYN3 
      interaction
- id: PMID:40205054
  title: Multimodal cell maps as a foundation for structural and functional 
    genomics.
  findings:
  - statement: Multimodal proteomics identifies SYN2 interactions
- id: PMID:8964517
  title: Cloning and sequencing analysis of a human synapsin IIb-encoding brain 
    cDNA.
  findings:
  - statement: Original cloning of human SYN2 isoform IIb
  - statement: Describes as abundant peripheral membrane protein of synaptic 
      vesicles
- id: DOI:10.1038/s41467-024-46256-1
  title: Synapsin 2a tetramerisation selectively controls the presynaptic 
    nanoscale organisation of reserve synaptic vesicles.
  findings:
  - statement: Syn2a tetramerization is required for reserve pool organization
  - statement: K337Q tetramerization-deficient mutant fails to rescue reserve 
      pool mobility
- id: DOI:10.7554/eLife.89687
  title: Synapsin E-domain is essential for alpha-synuclein function.
  findings:
  - statement: Synapsin E-domain is necessary and sufficient for alpha-synuclein
      function
  - statement: Direct binding between E-domain and alpha-synuclein
- id: DOI:10.1101/2023.03.20.533583
  title: Different mechanisms of synapsin-induced vesicle clustering at 
    inhibitory and excitatory synapses.
  findings:
  - statement: Two complementary mechanisms for synapsin-driven clustering LLPS 
      and tetramerization
  - statement: LLPS predominates at inhibitory synapses
  - statement: Tetramerization predominates at excitatory synapses (via Syn2a)
  - statement: ATP modulates the balance between LLPS and oligomerization
- id: DOI:10.1101/2023.08.08.549335
  title: The synapsin-dependent vesicle cluster is crucial for presynaptic 
    plasticity at a glutamatergic synapse in male mice.
  findings:
  - statement: Synapsin-dependent clustering essential for short-term plasticity
  - statement: Synapsin triple-KO shows decreased facilitation and altered LTP
core_functions:
- molecular_function:
    id: GO:0042802
    label: identical protein binding
  description: >-
    Homo- and hetero-oligomerization (tetramerization for Syn2a, heterodimers
    with SYN1/SYN3) is central to SYN2 function in vesicle clustering.
proposed_new_terms: []
suggested_questions:
- question: What are the specific differences in function between Syn2a and 
    Syn2b isoforms in human neurons?
- question: Does SYN2 have additional partners beyond the synapsin family and 
    alpha-synuclein?
suggested_experiments:
- description: Isoform-specific knockdown/rescue experiments in human 
    iPSC-derived neurons to determine Syn2a vs Syn2b contributions
- description: Structural studies of human SYN2-alpha-synuclein complex via 
    E-domain

Gene Description

Existing Annotations Review

Core Functions

Homo- and hetero-oligomerization (tetramerization for Syn2a, heterodimers with SYN1/SYN3) is central to SYN2 function in vesicle clustering.

References

Suggested Questions for Experts

Suggested Experiments

Deep Research

Falcon

Citations

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