Affinage

SCAMP5

Secretory carrier-associated membrane protein 5 · UniProt Q8TAC9

Length
235 aa
Mass
26.1 kDa
Annotated
2026-06-10
18 papers in source corpus 15 papers cited in narrative 15 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

SCAMP5 is a brain-enriched secretory membrane protein that regulates activity-dependent synaptic vesicle (SV) trafficking and cargo-specific recycling at presynaptic terminals (PMID:25057210, PMID:29562188). During strong neuronal activity it sustains SV endocytosis: its knockdown reduces total and recycling SV pool sizes, slows post-stimulation endocytosis, and lowers the threshold at which endocytosis can no longer compensate for exocytosis (PMID:25057210). Mechanistically, its 2/3 loop domain binds adaptor protein 2 (AP2) to drive release-site clearance at the active zone, such that loss of SCAMP5 produces synaptic depression and impaired SV protein clearance (PMID:29562188). The same 2/3 loop domain binds the cation/H+ exchanger NHE6 and is required for NHE6 axonal trafficking and presynaptic localization, thereby controlling SV acidification and setting glutamate quantal size, with NHE6 recruitment further enhanced during chemical LTP (PMID:33372133, PMID:33663553). SCAMP5 also organizes presynaptic autophagy by binding PI4KB at the trans-Golgi network to drive PtdIns4P production needed for AP-4-mediated ATG9A trafficking (PMID:40958389), and it links to calcium-regulated exocytosis through direct interaction with synaptotagmins and association with SNARE machinery (PMID:19234194, PMID:32020363). Loss-of-function and missense variants (R91W, G180W) disrupt these functions and underlie epilepsy and Parkinson's disease phenotypes, the latter via elevated α-synuclein and dopamine-neuron loss (PMID:31439720, PMID:32020363, PMID:41186735). In non-neuronal β-cells, SCAMP5 binds and downregulates VDAC1 to suppress Bax-dependent cytochrome c release and apoptosis (PMID:40953307).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2009 Medium

    Established SCAMP5 as a Golgi-resident, calcium-responsive secretory protein physically coupled to the exocytic machinery, defining its molecular context before any synaptic role was known.

    Evidence Subcellular fractionation, co-IP, and domain-truncation interaction mapping in cytokine-secreting cells

    PMID:19234194

    Open questions at the time
    • Direct synaptotagmin/SNARE binding shown by co-IP without reciprocal structural validation
    • Did not establish a presynaptic function
  2. 2009 Medium

    Linked SCAMP5 to endocytic control by showing its overexpression impairs endocytosis and aggravates polyglutamine aggregation, the first connection between SCAMP5 dosage and protein-handling disease.

    Evidence Overexpression, RNAi, and endocytosis assays plus in vivo tunicamycin in R6/2 and N171-82Q mouse models

    PMID:19240033

    Open questions at the time
    • Mechanism connecting SCAMP5 to endocytic machinery not defined here
    • Effect may be dosage artifact of overexpression
  3. 2010 Medium

    Showed SCAMP5 acts as a negative regulator of large dense-core vesicle exocytosis, indicating it tunes secretory output bidirectionally depending on vesicle class.

    Evidence shRNA silencing and overexpression with LDCV secretion assays in beta-TC3 cells

    PMID:20071347

    Open questions at the time
    • Molecular target of LDCV inhibition unidentified
    • Relationship to later SV-recycling role unresolved
  4. 2014 High

    Defined SCAMP5 as required for synaptic vesicle endocytosis specifically under high activity, resolving when SCAMP5 becomes rate-limiting at the synapse.

    Evidence shRNA knockdown with rescue and optical imaging of SV pool dynamics in rat hippocampal neurons

    PMID:25057210

    Open questions at the time
    • Did not identify the molecular interaction mediating endocytosis
    • Site of action at active zone not yet localized
  5. 2018 High

    Identified the AP2-binding 2/3 loop as the mechanistic basis for SCAMP5-driven release-site clearance, explaining the activity-dependent endocytic defect.

    Evidence Truncation interaction mapping, electrophysiology, super-resolution microscopy, and shRNA in neurons

    PMID:29562188

    Open questions at the time
    • Structural details of the SCAMP5-AP2 interface unknown
    • How clearance couples to subsequent vesicle reformation unresolved
  6. 2019 Medium

    Demonstrated a disease variant (G180W) reduces protein stability and acts dominant-negatively in vivo, validating SCAMP5 mutations as functionally consequential.

    Evidence Western blot and RNAi comparison with phenotypic analysis in Drosophila

    PMID:31439720

    Open questions at the time
    • No mammalian reconstitution of the variant
    • Molecular pathway disrupted by the residue not mapped
  7. 2020 Medium

    Connected the human R91W epilepsy mutation to excitatory transmission imbalance and loss of synaptotagmin-1 binding, tying SCAMP5 to SNARE-dependent release control.

    Evidence R91W knock-in mouse, single-neuron mEPSC/EPSC recordings, and interaction assays

    PMID:32020363

    Open questions at the time
    • Causal chain from lost synaptotagmin binding to hyperexcitability not fully resolved
    • Inhibitory synapse effects not characterized
  8. 2021 High

    Revealed that the 2/3 loop also binds NHE6 to traffic it to presynaptic SVs, establishing SCAMP5 as a controller of SV pH and glutamate quantal size, including during LTP.

    Evidence Truncation mapping, NHE6-KO epistasis, optical imaging, and electrophysiology plus chemical LTP induction

    PMID:33372133 PMID:33663553

    Open questions at the time
    • How a single loop coordinates both AP2 and NHE6 binding unresolved
    • Quantitative link between SV acidification and quantal size incomplete
  9. 2025 Medium

    Placed SCAMP5 upstream of presynaptic autophagy by identifying PI4KB binding at the TGN driving PtdIns4P-dependent AP-4/ATG9A trafficking, a distinct trafficking arm from its endocytic role.

    Evidence Binding analysis, shRNA depletion, PtdIns4P production assay, and ATG9A localization/autophagy assays

    PMID:40958389

    Open questions at the time
    • Independent replication of the SCAMP5-PI4KB axis pending
    • Coordination with AP2/NHE6 functions of SCAMP5 unknown
  10. 2025 Medium

    Extended SCAMP5 function to non-neuronal apoptosis control via VDAC1 downregulation and to Parkinson's-relevant α-synuclein handling, broadening its mechanistic repertoire beyond the synapse.

    Evidence Co-IP, ChIP for H3K4me3, and rescue in beta-cells; exosome/dopamine assays in PC12/SH-SY5Y and scamp5a-KO zebrafish

    PMID:40953307 PMID:41186735

    Open questions at the time
    • VDAC1 and α-synuclein arms not independently replicated
    • Whether these contexts share the synaptic trafficking mechanism unknown
  11. 2025 Medium

    Demonstrated cargo selectivity in SV recycling, showing SCAMP5 supports VGLUT2 but not VMAT2 vesicle recycling within the same neurons.

    Evidence CRISPR HA-VMAT2 knock-in mouse SV immunoisolation with SCAMP5 loss-of-function recycling analysis (preprint)

    PMID:bio_10.1101_2025.05.06.651945

    Open questions at the time
    • Preprint, not yet peer-reviewed
    • Molecular basis for cargo selectivity unidentified

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unknown how a single small membrane protein coordinates its multiple binding modes (AP2, NHE6, synaptotagmin, PI4KB, VDAC1) and what determines which arm dominates in a given cell type or activity state.
  • No structural model of SCAMP5 in complex with any partner
  • No unifying regulatory logic across endocytic, autophagic, and apoptotic functions

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 3 GO:0098772 molecular function regulator activity 2
Localization
GO:0005794 Golgi apparatus 3 GO:0031410 cytoplasmic vesicle 3 GO:0005886 plasma membrane 1
Pathway
R-HSA-112316 Neuronal System 3 R-HSA-5653656 Vesicle-mediated transport 3 R-HSA-5357801 Programmed Cell Death 1 R-HSA-9612973 Autophagy 1
Partners
AP2NHE6PI4KBSYT1VDAC1

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2009 hSCAMP5 localizes primarily to Golgi-associated compartments and translocates to the plasma membrane upon calcium ionophore stimulation; it co-distributes and complexes with SNARE molecules during this translocation and directly interacts with synaptotagmins via its cytosolic C-terminal tail, thereby linking SCAMP5 to calcium-regulated exocytosis of signal peptide-containing cytokines (CCL5). Subcellular fractionation, immunofluorescence confocal microscopy, membrane vesicle immunoisolation, co-immunoprecipitation, truncation/domain interaction analysis Journal of immunology Medium 19234194
2009 SCAMP5 impairs endocytosis when overexpressed, which in turn enhances mutant huntingtin (mtHTT) aggregation; conversely, SCAMP5 knockdown alleviates ER stress-induced mtHTT aggregation and endocytosis inhibition, establishing SCAMP5 as a regulator of polyglutamine protein accumulation via the endocytosis pathway. Cell-based aggregation assays, ectopic expression, RNAi knockdown, endocytosis assays, in vivo stereotactic and intraperitoneal tunicamycin injection in R6/2 and N171-82Q mouse models The Journal of biological chemistry Medium 19240033
2010 Gene silencing of Scamp5 in mouse beta-TC3 cells results in a 2-fold increase in stimulated secretion of large dense-core vesicles (LDCVs), while overexpression suppresses LDCV secretion, identifying SCAMP5 as a negative regulator of LDCV exocytosis. shRNA-mediated gene silencing, overexpression, LDCV secretion assay in mouse beta-TC3 cells, ultrastructural analysis of blood platelets Human molecular genetics Medium 20071347
2014 Knockdown of SCAMP5 in rat hippocampal neurons reduces total and recycling synaptic vesicle pool sizes, slows endocytosis after stimulation, and severely impairs endocytosis during strong stimulation, lowering the threshold at which SV endocytosis cannot compensate for exocytosis; these defects are rescued by shRNA-resistant SCAMP5. shRNA knockdown in cultured rat hippocampal neurons, optical imaging of SV pool dynamics, rescue with shRNA-resistant construct The Journal of neuroscience High 25057210
2018 The 2/3 loop domain of SCAMP5 directly interacts with adaptor protein 2 (AP2), and this interaction is critical for release site clearance at the active zone; SCAMP5 knockdown causes pronounced synaptic depression, slower SV pool recovery, frequency-dependent short-term depression, and defects in SV protein clearance at the active zone. Truncation analysis for protein-protein interaction, optical imaging, electrophysiology, super-resolution microscopy, shRNA knockdown Cell reports High 29562188
2019 A de novo missense variant (p.Gly180Trp) in SCAMP5 markedly reduces mutant protein levels in Drosophila fat body (indicating reduced expression or increased turnover) and causes dominant-negative effects on neuronal and eye phenotypes comparable to SCAMP RNAi, establishing this residue as functionally critical. Western blot of overexpressed proteins in Drosophila fat body, RNAi comparison, in vivo fly phenotypic analysis Journal of medical genetics Medium 31439720
2020 The SCAMP5 R91W mutation in a consanguineous family with epilepsy increases mEPSC frequency and evoked EPSC amplitude in single-neuron recordings, and disrupts the interaction between SCAMP5 and synaptotagmin 1, implicating SCAMP5 in regulation of the SNARE complex and neurotransmitter release balance. Knock-in mouse model (R91W), single-neuron electrophysiological recording (mEPSC, evoked EPSC), protein interaction analysis Human genetics Medium 32020363
2021 SCAMP5 directly interacts with the cation/H+ exchanger NHE6 via its 2/3 loop domain (binding the C-terminal region of NHE6), and this interaction is required for axonal trafficking and presynaptic localization of NHE6; SCAMP5 knockdown or disruption of this interaction causes hyperacidification of SVs and reduces glutamate quantal size, while NHE6 knockout occludes the SCAMP5 KD effect. Truncation-based protein-protein interaction analysis, shRNA knockdown, optical imaging, electrophysiological recording, genetic epistasis (NHE6 KO occlusion experiment) Proceedings of the National Academy of Sciences of the United States of America High 33372133
2021 SCAMP5-dependent recruitment of NHE6 to synaptic vesicles is further enhanced during chemical LTP (cLTP), with SCAMP5 knockdown completely abrogating the cLTP-induced increase in NHE6-positive presynaptic boutons, demonstrating that SCAMP5 regulates NHE6 recruitment during synaptic plasticity as well as at rest. Chemical LTP induction, shRNA knockdown, optical imaging of NHE6-positive presynaptic boutons Molecular brain Medium 33663553
2021 SCAMP5 localizes to the Golgi apparatus with dynamic Golgi-cell surface trafficking in plasmacytoid dendritic cells (pDCs), colocalizing with the interferon secretory pathway in transfected HEK cells. Lentiviral expression, subcellular localization imaging, colocalization analysis Lupus science & medicine Low 34728555
2022 In activated human pDCs, SCAMP5 colocalizes with IFNα as measured by ImageStream technology, supporting a role for SCAMP5 in type I interferon secretory trafficking. Flow cytometry, ImageStream colocalization (bright detail similarity scoring) Lupus science & medicine Low 35296555
2025 SCAMP5 deficiency in β-cells reduces CaV1.2 expression and insulin secretion; SCAMP5 directly interacts with VDAC1 and downregulates its protein expression, thereby preventing VDAC1-mediated Bax recruitment to mitochondria and consequent cytochrome c release, thus inhibiting apoptosis. ChREBP activated by hyperglycemia epigenetically represses SCAMP5 expression by reducing H3K4me3 at the Scamp5 promoter. Co-immunoprecipitation (SCAMP5-VDAC1 interaction), knockdown/overexpression in β-cells, cytochrome c release assay, Bax mitochondrial localization, ChIP for H3K4me3, CaV1.2 expression analysis Advanced science Medium 40953307
2025 SCAMP5 deficiency increases α-synuclein protein levels and oligomers, reduces α-synuclein secretion via exosomes, and decreases dopamine secretion in PC12/SH-SY5Y cells; R91W mutant SCAMP5 fails to rescue these effects; scamp5a knockout zebrafish exhibit bradykinesia, loss of dopamine neurons, reduced brain dopamine, and upregulated JNK signaling contributing to neuronal apoptosis. PC12/SH-SY5Y cell knockdown/overexpression, exosome isolation, dopamine measurement, zebrafish knockout model, transcriptome analysis, rescue with human wild-type vs. R91W SCAMP5 Human genetics Medium 41186735
2025 SCAMP5 is a novel binding partner of PI4KB/PI4KIIIβ at the trans-Golgi network (TGN); SCAMP5 controls PI4KB recruitment to the TGN and subsequent PtdIns4P production, which is required for AP-4 recruitment and AP-4-mediated ATG9A trafficking to presynaptic sites; SCAMP5 depletion therefore impairs presynaptic autophagosome formation and protein turnover. Protein-protein interaction analysis (SCAMP5-PI4KB binding), shRNA depletion, lipid (PtdIns4P) production assay, AP-4 and ATG9A localization imaging, presynaptic autophagy assays Autophagy Medium 40958389
2025 Loss of SCAMP5 selectively impairs recycling of VGLUT2-containing synaptic vesicles but not VMAT2-containing monoamine vesicles in the same neuronal population, revealing a cargo-specific role for SCAMP5 in SV recycling. CRISPR knock-in mouse (HA-VMAT2) for SV immunoisolation, SCAMP5 loss-of-function, functional recycling analysis in primary neurons bioRxivpreprint Medium bio_10.1101_2025.05.06.651945

Source papers

Stage 0 corpus · 18 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 SCAMP5, NBEA and AMISYN: three candidate genes for autism involved in secretion of large dense-core vesicles. Human molecular genetics 81 20071347
2009 SCAMP5 links endoplasmic reticulum stress to the accumulation of expanded polyglutamine protein aggregates via endocytosis inhibition. The Journal of biological chemistry 47 19240033
2009 Human SCAMP5, a novel secretory carrier membrane protein, facilitates calcium-triggered cytokine secretion by interaction with SNARE machinery. Journal of immunology (Baltimore, Md. : 1950) 43 19234194
2014 SCAMP5 plays a critical role in synaptic vesicle endocytosis during high neuronal activity. The Journal of neuroscience : the official journal of the Society for Neuroscience 36 25057210
2018 Impairment of Release Site Clearance within the Active Zone by Reduced SCAMP5 Expression Causes Short-Term Depression of Synaptic Release. Cell reports 21 29562188
2020 Deficiency of SCAMP5 leads to pediatric epilepsy and dysregulation of neurotransmitter release in the brain. Human genetics 18 32020363
2021 SCAMP5 plays a critical role in axonal trafficking and synaptic localization of NHE6 to adjust quantal size at glutamatergic synapses. Proceedings of the National Academy of Sciences of the United States of America 17 33372133
2019 De novo SCAMP5 mutation causes a neurodevelopmental disorder with autistic features and seizures. Journal of medical genetics 17 31439720
2021 SCAMP5 mediates activity-dependent enhancement of NHE6 recruitment to synaptic vesicles during synaptic plasticity. Molecular brain 10 33663553
2022 The role of SCAMP5 in central nervous system diseases. Neurological research 5 36217917
2020 Identification of an Identical de Novo SCAMP5 Missense Variant in Four Unrelated Patients With Seizures and Severe Neurodevelopmental Delay. Frontiers in pharmacology 5 33390987
2025 Deficiency of SCAMP5 Triggers Pancreatic β-Cell Secretory Dysfunction and Apoptosis. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 2 40953307
2022 Activation-induced colocalisation of SCAMP5 with IFNα in human plasmacytoid dendritic cells. Lupus science & medicine 2 35296555
2021 Investigations into SCAMP5, a candidate lupus risk gene expressed in plasmacytoid dendritic cells. Lupus science & medicine 2 34728555
2025 Analyzing the clinical characteristics of the SCAMP5 gene in gliomas and establishing a predictive model. Medicine 1 40184123
2025 Deficiency of SCAMP5 causes Parkinson's disease due to loss of dopamine neurons. Human genetics 1 41186735
2025 Case Report: A novel t(15;17)(q24;q11.2) translocation involving NF1::SCAMP5 fusion in a patient with myeloproliferative neoplasms. Frontiers in oncology 0 40761243
2025 SCAMP5 regulates AP-4-dependent sorting and trafficking of ATG9A for presynaptic autophagy via PI4KB/PI4KIIIβ recruitment and PtdInsP4 production at the TGN. Autophagy 0 40958389

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