Affinage

SCAMP2

Secretory carrier-associated membrane protein 2 · UniProt O15127

Length
329 aa
Mass
36.6 kDa
Annotated
2026-04-28
32 papers in source corpus 16 papers cited in narrative 16 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

SCAMP2 is a tetraspanning membrane protein of post-Golgi recycling vesicles that functions as a critical regulator of late-stage exocytotic membrane fusion and surface trafficking of diverse membrane transporters and channels. Its conserved cytoplasmic E peptide domain (between transmembrane spans 2 and 3) binds PI(4,5)P2 through electrostatic interactions and couples Arf6-stimulated phospholipase D1 activity to fusion pore formation and dilation during regulated exocytosis, as demonstrated by dominant-negative mutagenesis, siRNA knockdown, and biophysical studies in neuroendocrine cells (PMID:12124380, PMID:16030257, PMID:17713930, PMID:18171723). SCAMP2 directly interacts with and controls the exocytotic insertion or surface retention of multiple membrane transporters and channels—including SERT, DAT, NHE5, NHE7, NKCC2, hSVCT1, and Cav3.2 T-type calcium channels—through its E peptide domain and, in the case of NHE5, through an Arf6-dependent recycling endosome pathway (PMID:16870614, PMID:19276089, PMID:21205824, PMID:34980194). At the plasma membrane, SCAMP2 associates with SNARE proteins syntaxin 4, SNAP-23, syntaxin 1, and complexin, consistent with its role at fusion sites (PMID:12124380, PMID:12475951).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 1997 Medium

    Establishing SCAMP2 as a distinct gene product co-localizing with SCAMP1 and SCAMP3 in post-Golgi recycling vesicles provided the initial framework that SCAMPs function at shared vesicular transport sites and can form protein complexes.

    Evidence cDNA cloning, double-label immunofluorescence, co-immunoprecipitation, and chemical cross-linking in mammalian cells

    PMID:9224770 PMID:9378760

    Open questions at the time
    • No functional consequence of SCAMP1-SCAMP2 interaction was demonstrated
    • Stoichiometry and composition of SCAMP complexes undefined
    • Role in vesicle trafficking inferred from localization only
  2. 2002 High

    Demonstrating that the SCAMP2 E peptide inhibits exocytosis at a step beyond Ca2+/ATP-dependent priming and that E peptide point mutants block secretion (rescuable by lysophosphatidylcholine) established SCAMP2 as a direct participant in fusion pore formation rather than upstream vesicle priming.

    Evidence Synthetic peptide inhibition in permeabilized mast cells, dominant-negative overexpression in PC12 cells with amperometry, pharmacological rescue, co-immunoprecipitation with SNAP-23/syntaxin 4

    PMID:12124380 PMID:12475951

    Open questions at the time
    • Mechanism by which lysophosphatidylcholine bypasses SCAMP2 not fully resolved
    • Structural basis for E peptide–SNARE association unknown
  3. 2005 High

    Identification of SCAMP2 interaction with Arf6 and PLD1, and epistasis experiments showing SCAMP2 acts downstream of Arf6-PLD1 specifically at the fusion pore dilation step, positioned SCAMP2 within a defined signaling pathway controlling the final membrane merger event.

    Evidence Co-immunoprecipitation enhanced by depolarization/GTPγS, amperometry with SCAMP2 and Arf6 mutants, peptide-based PLD inhibition in PC12 cells

    PMID:16030257

    Open questions at the time
    • Direct physical contact between SCAMP2 and PLD1 not shown with purified proteins
    • Whether PLD1-generated phosphatidic acid acts on SCAMP2 or independently on the pore is unclear
  4. 2005 High

    Discovery that SCAMP2 binds NHE7 through the TM2–TM3 cytoplasmic loop and controls NHE7 recycling between TGN and recycling vesicles extended SCAMP2 function beyond exocytosis to regulation of organellar transporter trafficking.

    Evidence Yeast two-hybrid, co-immunoprecipitation, in vitro binding, deletion mutagenesis with redistribution phenotype by confocal microscopy

    PMID:15840657

    Open questions at the time
    • Directionality of SCAMP2 effect (anterograde vs. retrograde sorting of NHE7) not fully dissected
    • Physiological consequence of NHE7 mislocalization unknown
  5. 2006 High

    Showing that SCAMP2 binds SERT and reduces its surface expression through the E peptide domain—dissociating physical binding from functional regulation via the C201A mutation—established SCAMP2 as a trafficking regulator of neurotransmitter transporters.

    Evidence Yeast two-hybrid, GST pulldown, co-immunoprecipitation from rat brain, radioligand uptake, site-directed mutagenesis

    PMID:16870614

    Open questions at the time
    • Whether SCAMP2 regulates SERT via exocytosis, endocytosis, or surface retention was not resolved
    • In vivo relevance of SCAMP2–SERT interaction in brain not tested
  6. 2007 High

    Biophysical demonstration that the E peptide binds and sequesters PI(4,5)P2 through R204, and that corresponding full-length SCAMP2 mutations impair fusion pore opening probability and stability, provided the first molecular mechanism for how SCAMP2 regulates membrane fusion—through local PIP2 sequestration.

    Evidence EPR spectroscopy and NMR on E peptide–lipid interactions, alanine-scanning mutagenesis with amperometry in PC12 cells

    PMID:17713930

    Open questions at the time
    • Whether PIP2 sequestration and PLD1 coupling are mechanistically linked or parallel remains undefined
    • No structural model of E peptide within the bilayer at atomic resolution
  7. 2008 High

    Loss-of-function knockdown confirming that endogenous SCAMP2 is required for normal exocytotic event frequency, onset kinetics, and fusion pore dilation validated the gain-of-function mutant studies and established SCAMP2 as a necessary component of the exocytotic machinery.

    Evidence siRNA knockdown in PC12 cells with amperometry and calcium imaging

    PMID:18171723

    Open questions at the time
    • Redundancy with other SCAMPs not evaluated by double knockdown
    • Effect on kiss-and-run versus full fusion not quantitatively separated
  8. 2009 High

    Demonstrating that SCAMP2 increases NHE5 surface expression through an Arf6-dependent (but Rab11-independent) recycling endosome pathway linked SCAMP2's transporter trafficking function to the same Arf6 axis involved in its exocytotic role.

    Evidence In vitro binding, co-immunoprecipitation, surface biotinylation, dominant-negative GTPase epistasis in heterologous cells

    PMID:19276089

    Open questions at the time
    • Whether SCAMP2 acts as a cargo adaptor or a general fusion regulator in recycling endosomes is unresolved
    • Native neuronal validation lacking
  9. 2011 High

    Extension of SCAMP2's transporter regulatory repertoire to NKCC2 (reducing exocytotic insertion) and DAT (reducing surface levels) demonstrated the generality of E peptide–dependent surface trafficking control across functionally diverse cargo proteins.

    Evidence Yeast two-hybrid, co-immunoprecipitation, MesNa cleavage assay distinguishing exo- from endocytosis for NKCC2; CoIP and FRET for DAT

    PMID:21205824 PMID:21295544

    Open questions at the time
    • Why SCAMP2 increases surface expression of some cargoes (NHE5, hSVCT1) but decreases others (SERT, DAT, NKCC2, Cav3.2) is mechanistically unexplained
    • Cargo selectivity determinants not mapped
  10. 2022 High

    Identification of SCAMP2 as a regulator of Cav3.2 T-type calcium channel surface expression—nearly abolishing current by blocking forward trafficking without reducing total protein—extended SCAMP2's E peptide–dependent trafficking control to ion channels.

    Evidence Whole-cell patch clamp, intramembrane charge movement recording, E peptide mutagenesis in heterologous expression system

    PMID:34980194

    Open questions at the time
    • Endogenous interaction not validated in native neurons
    • Trafficking step (ER exit, Golgi, recycling) affected by SCAMP2 not identified
  11. 2023 Medium

    Discovery that SCAMP2 interacts with hSVCT1 and positively regulates vitamin C uptake, and that SCAMP2 knockdown impairs hiPSC neuronal differentiation, expanded the functional scope of SCAMP2 to nutrient transport and developmental processes.

    Evidence Affinity proteomics, co-immunoprecipitation, 14C-ascorbic acid uptake, siRNA knockdown, hiPSC differentiation assay

    PMID:36632962

    Open questions at the time
    • Causal link between SCAMP2-dependent vitamin C uptake and neuronal differentiation not established
    • Single-lab observation awaiting independent replication

Open questions

Synthesis pass · forward-looking unresolved questions
  • The mechanistic basis for SCAMP2's bidirectional regulation of cargo surface expression—increasing some cargoes (NHE5, hSVCT1) while decreasing others (SERT, DAT, NKCC2, Cav3.2)—and whether this reflects cargo-specific adaptor interactions or context-dependent fusion regulation remains an open question.
  • No structural model of full-length SCAMP2 exists
  • No in vivo animal model phenotype reported
  • Relationship between PIP2 sequestration and cargo-specific trafficking outcomes is undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0008289 lipid binding 1
Localization
GO:0031410 cytoplasmic vesicle 3 GO:0005794 Golgi apparatus 2 GO:0005886 plasma membrane 2
Pathway
R-HSA-5653656 Vesicle-mediated transport 5 R-HSA-382551 Transport of small molecules 4 R-HSA-112316 Neuronal System 2
Partners
ARF6PLD1SLC6A3SLC6A4SLC9A7SNAP23STX1ASTX4

Evidence

Reading pass · 16 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2002 A synthetic peptide (E peptide: CWYRPIYKAFR) from the conserved cytoplasmic segment between transmembrane spans 2 and 3 of SCAMP2 potently inhibits exocytosis in permeabilized mast cells, acting at a very late step beyond Ca2+/ATP-dependent priming, directly associated with membrane fusion. SCAMP2 co-immunoprecipitates with SNARE proteins SNAP-23 and syntaxin 4 at the plasma membrane. Permeabilized cell exocytosis assay, peptide inhibition, co-immunoprecipitation, immunofluorescence The Journal of biological chemistry High 12124380
2002 SCAMP2 localizes to plasma membranes at putative docking/fusion sites with syntaxin1 and complexin in PC12 cells. Overexpression of SCAMP2 point mutants in the E peptide (but not wild-type SCAMP2) dose-dependently inhibits depolarization-induced and calcium-stimulated secretion; this inhibition is largely rescued by lysophosphatidylcholine, implicating SCAMP2 E peptide in fusion pore formation during granule exocytosis. Regulated overexpression of point mutants, amperometry, pharmacological rescue with lysophosphatidylcholine, confocal colocalization Molecular biology of the cell High 12475951
2005 SCAMP2 interacts with Arf6 and phospholipase D1 (PLD1) in PC12 cells; co-immunoprecipitation is enhanced after cell depolarization and GTPγS treatment. A SCAMP2-derived E peptide suppresses PLD activity. A SCAMP2 point mutant with decreased Arf6 association inhibits early membrane fusion events and fusion pore dilation, while mutant Arf6 deficient in PLD1 activation only inhibits early fusion events, placing SCAMP2 downstream of Arf6-PLD1 in exocytosis and specifically linking it to fusion pore formation. Co-immunoprecipitation, amperometry, dominant-negative mutants, peptide inhibition of PLD activity Molecular biology of the cell High 16030257
2007 SCAMP2 E peptide binds and sequesters PI(4,5)P2 within membranes through an electrostatic mechanism. EPR analysis shows R4 (R204 in full-length SCAMP2) is critical for PIP2 binding. Corresponding SCAMP2 point mutants (SC2-R204A, SC2-W202A) inhibit dense core vesicle exocytosis in PC12 cells, specifically decreasing fusion pore opening probability and stability of initially opened pores, establishing that SCAMP2-PIP2 interaction regulates fusion pore formation. EPR spectroscopy, NMR, alanine-scanning mutagenesis of full-length SCAMP2, amperometry in PC12 cells Biochemistry High 17713930
2006 SCAMP2 interacts with the serotonin transporter (SERT) via yeast two-hybrid, GST pulldown, and co-immunoprecipitation from rat brain homogenate. Co-expression of SCAMP2 with SERT decreases cell-surface SERT and 5-HT uptake. SCAMP2 co-localizes with SERT in lipid raft/syntaxin 1A-containing structures. A single point mutation C201A in the SCAMP2 E peptide abolishes SCAMP2-mediated SERT downregulation without disrupting physical interaction, indicating the E peptide domain mediates the functional effect on trafficking. Yeast two-hybrid, GST pulldown, co-immunoprecipitation from brain homogenate, confocal microscopy, radioligand uptake assay, site-directed mutagenesis The Journal of biological chemistry High 16870614
2005 SCAMP2 interacts with the C-terminus of NHE7 (organellar Na+/K+/H+ exchanger) identified by yeast two-hybrid; interaction confirmed by co-immunolocalization, co-immunoprecipitation, co-sedimentation in sucrose gradients, and in vitro binding. SCAMP2 binds NHE7 through a cytoplasmic TM2-TM3 loop (residues 184-208). Deletion of this loop or overexpression of the TM2-TM3 construct redistributes NHE7 from TGN to scattered recycling vesicles, indicating SCAMP2 participates in shuttling NHE7 between recycling vesicles and TGN. Yeast two-hybrid, co-immunoprecipitation, co-sedimentation, in vitro binding assay, deletion mutagenesis, confocal microscopy Journal of cell science High 15840657
2009 SCAMP2 binds directly to both the N- and C-terminal cytosolic extensions of the brain-enriched Na+/H+ exchanger NHE5, as shown by in vitro protein-protein interaction assays and co-immunoprecipitation. Co-expression of SCAMP2 (but not SCAMP5) increases NHE5 cell-surface abundance and transport activity. SCAMP2-specific N-terminal cytosolic domain is required for this effect. SCAMP2-mediated NHE5 surface targeting is reversed by dominant-negative Arf6 but not dominant-negative Rab11, placing SCAMP2 in an Arf6-dependent recycling endosome pathway. In vitro protein-protein interaction assay, co-immunoprecipitation, surface biotinylation, dominant-negative GTPase epistasis, confocal microscopy The Journal of biological chemistry High 19276089
2011 SCAMP2 interacts with the renal NKCC2 co-transporter identified by yeast two-hybrid and confirmed by co-immunoprecipitation and confocal co-localization. SCAMP2 overexpression decreases NKCC2 cell-surface abundance and transport activity by reducing exocytotic insertion (not endocytic retrieval), as shown by sodium 2-mercaptoethane sulfonate cleavage assay. The C201A E peptide mutation of SCAMP2 abolishes this regulation, indicating the E peptide domain mediates the effect on exocytotic trafficking. Yeast two-hybrid, co-immunoprecipitation, confocal microscopy, surface biotinylation, MesNa cleavage assay, site-directed mutagenesis The Journal of biological chemistry High 21205824
2011 SCAMP2 interacts with and regulates the dopamine transporter (DAT). DAT-SCAMP2 interaction is confirmed by co-immunoprecipitation and FRET microscopy. Co-expression of SCAMP2 with DAT reduces dopamine uptake and cell-surface DAT levels, mirroring its previously described effect on SERT. Co-immunoprecipitation, FRET microscopy, dopamine uptake assay, surface expression measurement Biochemical and biophysical research communications Medium 21295544
2008 RNA interference-mediated knockdown of SCAMP2 in PC12 cells decreases the number and frequency of depolarization-induced dense core vesicle exocytotic events and delays the onset of exocytosis, as measured by amperometry. SCAMP2 knockdown also increases rapid fusion pore closure and decreases pore dilation without affecting upstream DCV distribution or calcium signaling, placing SCAMP2 specifically at the final membrane fusion step. siRNA knockdown, amperometry, calcium imaging American journal of physiology. Cell physiology High 18171723
1997 SCAMP1 and SCAMP2 extensively co-localize in post-Golgi recycling carrier membranes and can be co-immunoprecipitated, indicating they form protein complexes that may include homomultimers. Cross-linking studies suggest SCAMP1 forms homomultimers in situ. Co-immunoprecipitation, chemical cross-linking, immunocytochemistry, velocity centrifugation Journal of cell science Medium 9224770
1997 Three mammalian SCAMPs (1, 2, 3) are products of distinct genes with highly conserved sequences and extensively co-localize in post-Golgi recycling vesicles as shown by double-label immunofluorescence, suggesting shared function at the same vesicular transport sites rather than separate pathways. cDNA cloning, immunofluorescence double labeling, subcellular fractionation Journal of cell science Medium 9378760
1998 SCAMP1 and SCAMP3, but not SCAMP2, are tyrosine phosphorylated in EGF-stimulated murine fibroblasts overexpressing EGFR. SCAMP3 phosphorylation is stimulated by EGFR in vitro, and EGF induces SCAMP-EGFR co-immunoprecipitation, suggesting phosphorylation is linked to EGFR internalization/downregulation. SCAMP2 is specifically excluded from this phosphorylation. In vitro kinase assay, co-immunoprecipitation, phosphatase treatment, vanadate inhibition Molecular biology of the cell Medium 9658162
2022 SCAMP2 was identified as a novel Cav3.2 T-type calcium channel interacting protein. Co-expression of SCAMP2 with Cav3.2 in mammalian cells nearly abolishes whole-cell T-type current by reducing channel surface expression (evidenced by loss of intramembrane charge movement without reduction in total protein). Single amino acid mutations in the SCAMP2 E peptide partly reverse this effect. The downregulation also applies to Cav3.1 and Cav3.3 isoforms. Co-expression, whole-cell patch clamp, intramembrane charge movement recording, site-directed mutagenesis of E peptide Molecular brain High 34980194
2023 SCAMP2 was identified as a novel interacting protein of the human sodium-dependent vitamin C transporter hSVCT1 by affinity pull-down proteomics and confirmed by co-immunoprecipitation. Co-expression of hSVCT1 and SCAMP2 leads to co-localization at intracellular structures and plasma membrane. Overexpression of SCAMP2 potentiates ascorbic acid uptake; knockdown of SCAMP2 decreases uptake. SCAMP2 knockdown also impairs hiPSC differentiation to neurons. Affinity tagging proteomics, co-immunoprecipitation, confocal microscopy, 14C-ascorbic acid uptake assay, siRNA knockdown, hiPSC neuronal differentiation International journal of biological macromolecules Medium 36632962
2007 SCAMP2 protein was identified by immunoelectron microscopy in platelet alpha-granule membranes, establishing its subcellular localization to this secretory organelle. Immunoelectron microscopy, sucrose gradient fractionation, mass spectrometry Journal of thrombosis and haemostasis : JTH Medium 17723134

Source papers

Stage 0 corpus · 32 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2007 Proteomic analysis of platelet alpha-granules using mass spectrometry. Journal of thrombosis and haemostasis : JTH 227 17723134
2009 A mobile secretory vesicle cluster involved in mass transport from the Golgi to the plant cell exterior. The Plant cell 150 19376937
2017 Glucocorticoids, genes and brain function. Progress in neuro-psychopharmacology & biological psychiatry 105 29180230
2003 Binding of peptides with basic and aromatic residues to bilayer membranes: phenylalanine in the myristoylated alanine-rich C kinase substrate effector domain penetrates into the hydrophobic core of the bilayer. The Journal of biological chemistry 97 12670959
2006 Subcellular redistribution of the serotonin transporter by secretory carrier membrane protein 2. The Journal of biological chemistry 69 16870614
2012 Genome-wide association uncovers shared genetic effects among personality traits and mood states. American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 68 22628180
1997 Three mammalian SCAMPs (secretory carrier membrane proteins) are highly related products of distinct genes having similar subcellular distributions. Journal of cell science 62 9378760
2005 Secretory carrier membrane proteins interact and regulate trafficking of the organellar (Na+,K+)/H+ exchanger NHE7. Journal of cell science 56 15840657
2005 SCAMP2 interacts with Arf6 and phospholipase D1 and links their function to exocytotic fusion pore formation in PC12 cells. Molecular biology of the cell 55 16030257
2002 Perturbation of a very late step of regulated exocytosis by a secretory carrier membrane protein (SCAMP2)-derived peptide. The Journal of biological chemistry 51 12124380
2002 Role of secretory carrier membrane protein SCAMP2 in granule exocytosis. Molecular biology of the cell 44 12475951
2009 Subcellular localization of the antidepressant-sensitive norepinephrine transporter. BMC neuroscience 38 19545450
2021 Cross-ancestry GWAS meta-analysis identifies six breast cancer loci in African and European ancestry women. Nature communications 36 34234117
1998 Tyrosine phosphorylation of selected secretory carrier membrane proteins, SCAMP1 and SCAMP3, and association with the EGF receptor. Molecular biology of the cell 34 9658162
2002 Function of the t-SNARE SNAP-23 and secretory carrier membrane proteins (SCAMPs) in exocytosis in mast cells. Molecular immunology 33 12217404
2007 Secretory carrier membrane protein SCAMP2 and phosphatidylinositol 4,5-bisphosphate interactions in the regulation of dense core vesicle exocytosis. Biochemistry 32 17713930
1997 Evidence for colocalization and interaction between 37 and 39 kDa isoforms of secretory carrier membrane proteins (SCAMPs). Journal of cell science 31 9224770
2009 Secretory Carrier Membrane Protein 2 Regulates Cell-surface Targeting of Brain-enriched Na+/H+ Exchanger NHE5. The Journal of biological chemistry 30 19276089
2011 Secretory carrier membrane protein 2 regulates exocytic insertion of NKCC2 into the cell membrane. The Journal of biological chemistry 29 21205824
2008 Nonredundant function of secretory carrier membrane protein isoforms in dense core vesicle exocytosis. American journal of physiology. Cell physiology 25 18171723
2011 Modulation of the dopamine transporter by interaction with Secretory Carrier Membrane Protein 2. Biochemical and biophysical research communications 18 21295544
2009 Exo- and endocytotic trafficking of SCAMP2. Plant signaling & behavior 12 20514246
2014 Genome-wide association analysis to identify SNP markers affecting teat numbers in an F2 intercross population between Landrace and Korean native pigs. Molecular biology reports 11 25055975
2022 Secretory carrier-associated membrane protein 2 (SCAMP2) regulates cell surface expression of T-type calcium channels. Molecular brain 9 34980194
2020 Sucrose starvation induces the degradation of proteins in trans-Golgi network and secretory vesicle cluster in tobacco BY-2 cells. Bioscience, biotechnology, and biochemistry 7 32338160
2009 Enterostatin alters protein trafficking to inhibit insulin secretion in Beta-TC6 cells. Peptides 7 19563849
2026 In-Silico identification and optimization of therapeutic peptides against breast cancer via transcriptomic profiling. Molecular diversity 1 41483317
2025 Blood biomarker fingerprints in a cohort of patients with CHRNE-related congenital myasthenic syndrome. Acta neuropathologica communications 1 39948634
2023 Reduction in hippocampal GABAergic transmission in a low birth weight rat model of depression. Acta neuropsychiatrica 1 36896595
2023 Secretory carrier-associated membrane protein 5 regulates cell-surface targeting of T-type calcium channels. Channels (Austin, Tex.) 1 37389974
2025 Longitudinal transcriptomic and epigenetic analysis of the blood in two astronauts. Scientific reports 0 40715343
2023 Vitamin C transport in neurons and epithelia is regulated by secretory carrier-associated membrane protein-2 (SCAMP2). International journal of biological macromolecules 0 36632962