Alternative titles; symbols
HGNC Approved Gene Symbol: VAMP2
Cytogenetic location: 17p13.1 Genomic coordinates (GRCh38): 17:8,159,147-8,162,948 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 17p13.1 | Neurodevelopmental disorder with hypotonia and autistic features with or without hyperkinetic movements | 618760 | Autosomal dominant | 3 |
Intracellular vesicles travel among cellular compartments and deliver their specific cargo to target membranes by membrane fusion. The specificity of cargo delivery and membrane fusion is controlled, in part, by the pairing of vesicle v-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), such as VAMP2, with target membrane t-SNAREs (summary by McNew et al., 2000). The VAMP2 protein plays an important role in neurotransmitter release at the presynaptic plasma membrane of neuronal synapses in the central nervous system, including vesicular fusion, neurotransmitter release, and vesicle endocytosis (summary by Salpietro et al., 2019).
Archer et al. (1990) isolated and characterized cosmid clones containing the human genes encoding synaptobrevins 1 and 2. Their coding regions are highly homologous, being interrupted at identical positions by introns of different size and sequence. The deduced synaptobrevin-2 protein contains 116 amino acids.
By analyzing microarray data from human postmortem brain tissue, Salpietro et al. (2019) found the highest expression of VAMP2 in the frontal lobes and putamen.
Hunt et al. (1994) presented evidence that synaptobrevin participates in neurotransmitter release at a step between docking and fusion.
Using yeast 2-hybrid analysis and in vitro binding assays, Martincic et al. (1997) showed that rat Pra1 (RABAC1; 604925) bound prenylated Rab GTPases, including Rab3a (179490) and Rab1 (179508), but not other small Ras-like GTPases. Pra1 also interacted with Vamp2, but not Vamp1 (185880) or cellubrevin (VAMP3; 603657). Interaction with Vamp2 involved the N-terminal proline-rich domain of Vamp2 and required the C-terminal transmembrane domain of Vamp2. Deletion analysis showed that both an N-terminal region spanning amino acids 30 to 54 and the extreme C-terminal domain of Pra1 were required for binding both Rab GTPases and Vamp1. Martincic et al. (1997) suggested that PRA1 may link Rab proteins and VAMP2 in the control of vesicle docking and fusion.
McNew et al. (2000) tested all of the potential v-SNAREs encoded in the yeast genome for their capacity to trigger fusion by partnering with t-SNAREs that mark the Golgi, the vacuole, and the plasma membrane. McNew et al. (2000) found that, to a marked degree, the pattern of membrane flow in the cell is encoded and recapitulated by its isolated SNARE proteins, as predicted by the SNARE hypothesis. The heterodimer of syntaxin Sso1, which is homologous to syntaxin-1A, and Sec9, which is homologous to SNAP25, is a t-SNARE of the yeast plasma membrane, with Snc2, which is homologous to VAMP2, as its cognate v-SNARE. Thus, the yeast plasma membrane t-SNARE complex closely resembles its neuronal counterpart (Weber et al., 1998).
SNARE proteins normally face the cytoplasm, within which their helical domains can pair to link membranes for fusion. To ascertain whether SNAREs can fuse cells, Hu et al. (2003) flipped their orientation and engineered cognate cells to express either the v- or t-SNAREs. Hu et al. (2003) found that cells expressing the interacting domains of v- (VAMP2) and t-SNAREs (syntaxin 1A and SNAP25) on the cell surface fused spontaneously, demonstrating that SNAREs are sufficient to fuse biologic membranes.
To investigate the role of astrocytes in regulating synaptic transmission, Pascual et al. (2005) generated inducible transgenic mice that expressed a dominant-negative SNARE domain selectively in astrocytes to block the release of transmitters from these glial cells. By releasing ATP, which accumulates as adenosine, astrocytes tonically suppressed synaptic transmission, thereby enhancing the dynamic range for long-term potentiation and mediated activity-dependent, heterosynaptic depression. Pascual et al. (2005) concluded that their results indicated that astrocytes are intricately linked in the regulation of synaptic strength and plasticity and provide a pathway for synaptic crosstalk.
Burre et al. (2010) showed that maintenance of continuous presynaptic SNARE complex assembly requires a nonclassical chaperone activity mediated by synucleins. Specifically, alpha-synuclein (163890) directly bound to the SNARE protein SYB2/VAMP2 and promoted SNARE complex assembly. Moreover, triple-knockout mice lacking synucleins developed age-dependent neurologic impairments, exhibited decreased SNARE complex assembly, and died prematurely. Burre et al. (2010) concluded that synucleins may function to sustain normal SNARE complex assembly in a presynaptic terminal during aging.
Shi et al. (2012) used in vitro membrane fusion and exocytosis assays that paired liposomes containing a t-SNARE complex of rat syntaxin-1A and mouse Snap25 with flat nanodisc proteolipid particles containing the mouse v-SNARE Vamp2. They found that a single Vamp2 protein could mediate efficient SNARE complex formation, vesicle fusion, and lipid mixing between the liposome and nanodisc, but not pore formation or release of liposome cargo. Cargo release was highly sensitive to the number of SNARE complexes formed between the liposome and nanodisc, and maximum efflux required 3 or 4 Vamp2 proteins per nanodisc. Use of chimeric proteins revealed that the membrane-spanning transmembrane domain of VAMP2 mediated efficient release of vesicle contents by stabilizing the nascent fusion pore formed between VAMP2 and the t-SNAREs. Shi et al. (2012) concluded that membrane fusion requires only a single SNARE complex between membranes, but pore formation, widening, and stabilization, as well as efficient cargo efflux, requires several SNARE complexes.
Vacuolar proton-ATPase (V-ATPase), which generates vesicular proton gradients and membrane potential, is made up of a peripheral multisubunit V1 sector that hydrolyzes ATP and a membrane V0 sector that translocates protons. Using a yeast 2-hybrid screen of a rat brain cDNA library, Di Giovanni et al. (2010) found that Vamp2 interacted with the isolated loop 3.4 (L3.4) of accessory V0 subunit c (ATP6V1C1; 603097). Vamp2 also interacted with full-length c subunit expressed in HEK293 cells. Domain analysis revealed that a juxtamembrane region of Vamp2, but not its transmembrane domain, interacted with the c subunit. This region of Vamp2, which includes a crucial WW motif, also interacted with Ca(2+)-calmodulin (see CALM1, 114180). Calmodulin and V0 subunit c completed for binding to Vamp2, possibly in a Ca(2+)-dependent manner. Injection of the c-subunit L3.4 peptide into rat cortical slices and cultured sympathetic neurons induced substantial decrease in neurotransmitter release probability, inhibiting glutamatergic and cholinergic transmission, respectively. L3.4 did not affect synaptic vesicle proton pump activity.
Crystal Structure
Stein et al. (2009) reported the x-ray structure of the neuronal SNARE complex, consisting of the SNARE motifs of rat syntaxin-1A, Snap25, and synaptobrevin-2 (VAMP2), with the C-terminal linkers and transmembrane regions of both syntaxin-1A and synaptobrevin-2 at 3.4-angstrom resolution. The structure showed that assembly proceeds beyond the known core SNARE complex, resulting in a continuous helical bundle that is further stabilized by side-chain interactions in the linker region. The results suggested that the final phase of SNARE assembly is directly coupled to membrane merger.
Physical Chemistry
Gao et al. (2012) used optical tweezers to observe in a cell-free reconstitution experiment in real time a long-sought SNARE assembly intermediate in which only the membrane-distal amino-terminal half of the bundle is assembled. Their findings supported the zippering hypothesis, but suggested that zippering proceeds through 3 sequential binary switches, not continuously, in the amino- and carboxyl-terminal halves of the bundle and the linker domain. The half-zippered intermediate was stabilized by externally applied force that mimicked the repulsion between apposed membranes being forced to fuse. This intermediate then rapidly and forcefully zippered, delivering free energy of 36 k(B)T (where k(B) is the Boltzmann constant and T is temperature) to mediate fusion.
Archer et al. (1990) determined that the SYB2 gene contains 5 exons spanning approximately 3 kb.
By Southern analysis of rodent-human somatic cell hybrids, Archer et al. (1990) mapped the SYB2 gene to human chromosome 17. By study of various deleted chromosomes 17 in somatic cell hybrids, they showed that the gene is located in region 17pter-p12. Archer et al. (1990) identified a PstI RFLP at the SYB2 locus. By fluorescence in situ hybridization, Zoraqi et al. (2000) localized the SYB2 gene to 17p12.
By analysis of somatic cell hybrids between mouse cells and those of Chinese hamster or rat, Archer et al. (1990) assigned the Syb2 gene in the mouse to chromosome 11.
In 5 unrelated individuals with neurodevelopmental disorder with hypotonia and autistic features with or without hyperkinetic movements (NEDHAHM; 618760), Salpietro et al. (2019) identified 5 different de novo heterozygous mutations in the VAMP2 gene (S755P, 185881.0001; E78A, 185881.0002; F77S, 185881.0003; V43del, 185881.0004; and I45del, 185881.0005). The mutations, which were found by whole-exome sequencing and confirmed by Sanger sequencing, were not present in the gnomAD database. Three patients, who carried missense mutations in the C-terminal region of the vSNARE domain, had a more severe disorder with cortical visual impairment and hyperkinetic movements, whereas the other 2 patients, who carried in-frame deletions of conserved residues, had a less severe disorder and were able to achieve some walking and speech. In vitro functional expression studies using recombinant S75P and E78A mutations in a lipid-mixing assay showed that the S75P variant reduced the rate and extent of vesicle fusion to about 10 to 25% that of wildtype and showed a dominant-negative effect, whereas the E78A variant had little to no effect on vesicle fusion. Studies of the F77S mutation could not be performed due to technical difficulties; studies of the V43del and I45del variants were not performed.
Schoch et al. (2001) generated mice deficient in Vamp2 and used electrophysiologic methods to measure fusion. In the absence of synaptobrevin-2, spontaneous synaptic vesicle fusion and fusion induced by hypertonic sucrose were decreased approximately 10-fold, but fast calcium-triggered fusion was decreased more than 100-fold. Thus, Schoch et al. (2001) concluded that synaptobrevin-2 may function in catalyzing fusion reactions and stabilizing fusion intermediates but is not absolutely required for synaptic fusion.
Deak et al. (2004) found a defect in the endocytosis of synaptic vesicles in Vamp2 -/- mouse neurons. They concluded that Vamp2 is essential for 2 fast synapse-specific membrane trafficking reactions: fast exocytosis for neurotransmitter release, and fast endocytosis for the rapid reuse of synaptic vesicles.
In a 3-year-old Italian girl (individual 1) with neurodevelopmental disorder with hypotonia and autistic features with hyperkinetic movements (NEDHAHM; 618760), Salpietro et al. (2019) identified a de novo heterozygous c.223T-C transition (c.223T-C, NM_014232) in the VAMP2 gene, resulting in a ser75-to-pro (S75P) substitution at a highly conserved residue in the C-terminal region of the vSNARE domain. The mutation, which was found by trio-based whole-exome sequencing and confirmed by Sanger sequencing, was not found in the ExAC or gnomAD databases. In vitro functional expression studies using the recombinant S75P mutation in a lipid-mixing assay showed that the variant reduced the rate and extent of vesicle fusion to about 10 to 25% that of wildtype and showed a dominant-negative effect.
In a 10-year-old Caucasian boy (individual 2) with neurodevelopmental disorder with hypotonia and autistic features with hyperkinetic movements (NEDHAHM; 618760), Salpietro et al. (2019) identified a de novo heterozygous c.233A-C transversion (c.233A-C, NM_014232) in the VAMP2 gene, resulting in a glu78-to-ala (E78A) substitution at a highly conserved residue in the C-terminal region of the vSNARE domain. The mutation, which was found by trio-based whole-exome sequencing and confirmed by Sanger sequencing, was not found in the ExAC or gnomAD databases. In vitro functional expression studies using the recombinant E78A mutation in a lipid-mixing assay showed that the variant had little to no effect on vesicle fusion compared to wildtype.
In a 13-year-old Spanish boy (individual 3) with neurodevelopmental disorder with hypotonia and autistic features with hyperkinetic movements (NEDHAHM; 618760), Salpietro et al. (2019) identified a de novo heterozygous c.230T-C transition (c.230T-C, NM_014232) in the VAMP2 gene, resulting in a phe77-to-ser (F77S) substitution at a highly conserved residue in the C-terminal region of the vSNARE domain. The mutation, which was found by trio-based whole-exome sequencing and confirmed by Sanger sequencing, was not found in the ExAC or gnomAD databases. Functional studies of the variant and studies of patient cells were not performed due to technical difficulties.
In a 14-year-old Caucasian boy (individual 4) with neurodevelopmental disorder with hypotonia and autistic features without hyperkinetic movements (NEDHAHM; 618760), Salpietro et al. (2019) identified a de novo heterozygous in-frame 3-bp deletion (c.138_130delTGG, NM_014232) in the VAMP2 gene, resulting in deletion of the highly conserved residue Val43 (Val43del) in the vSNARE domain. The mutation, which was found by whole-exome sequencing and confirmed by Sanger sequencing, was not found in the ExAC or gnomAD databases. Functional studies of the variant and studies of patient cells were not performed.
In a 3-year-old French girl (individual 5) with neurodevelopmental disorder with hypotonia and autistic features without hyperkinetic movements (NEDHAHM; 618760), Salpietro et al. (2019) identified a de novo heterozygous in-frame 3-bp deletion (c.135_137delCAT, NM_014232) in the VAMP2 gene, resulting in deletion of the highly conserved residue Ile45 (Ile45del) in the vSNARE domain. The mutation, which was found by whole-exome sequencing and confirmed by Sanger sequencing, was not found in the ExAC or gnomAD databases. Functional studies of the variant and studies of patient cells were not performed.
Archer, B. T., III, Ozcelik, T., Jahn, R., Francke, U., Sudhof, T. C. Structures and chromosomal localizations of two human genes encoding synaptobrevins 1 and 2. J. Biol. Chem. 265: 17267-17273, 1990. [PubMed: 1976629]
Burre, J., Sharma, M., Tsetsenis, T., Buchman, V., Etherton, M. R., Sudhof, T. C. Alpha-synuclein promotes SNARE-complex assembly in vivo and in vitro. Science 329: 1663-1667, 2010. [PubMed: 20798282] [Full Text: https://doi.org/10.1126/science.1195227]
Deak, F., Schoch, S., Liu, X., Sudhof, T. C., Kavalali, E. T. Synaptobrevin is essential for fast synaptic-vesicle endocytosis. Nature Cell Biol. 6: 1102-1108, 2004. [PubMed: 15475946] [Full Text: https://doi.org/10.1038/ncb1185]
Di Giovanni, J., Boudkkazi, S., Mochida, S., Bialowas, A., Samari, N., Leveque, C., Youssouf, F., Brechet, A., Iborra, C., Maulet, Y., Moutot, N., Debanne, D., Seagar, M., El Far, O. V-ATPase membrane sector associates with synaptobrevin to modulate neurotransmitter release. Neuron 67: 268-279, 2010. [PubMed: 20670834] [Full Text: https://doi.org/10.1016/j.neuron.2010.06.024]
Gao, Y., Zorman, S., Gundersen, G., Xi, Z., Ma, L., Sirinakis, G., Rothman, J. E., Zhang, Y. Single reconstituted neuronal SNARE complexes zipper in three distinct stages. Science 337: 1340-1343, 2012. [PubMed: 22903523] [Full Text: https://doi.org/10.1126/science.1224492]
Hu, C., Ahmed, M., Melia, T. J., Sollner, T. H., Mayer, T., Rothman, J. E. Fusion of cells by flipped SNAREs. Science 300: 1745-1749, 2003. [PubMed: 12805548] [Full Text: https://doi.org/10.1126/science.1084909]
Hunt, J. M., Bommert, K., Charlton, M. P., Kistner, A., Habermann, E., Augustine, G. J., Betz, H. A post-docking role for synaptobrevin in synaptic vesicle fusion. Neuron 12: 1269-1279, 1994. [PubMed: 8011337] [Full Text: https://doi.org/10.1016/0896-6273(94)90443-x]
Martincic, I., Peralta, M. E., Ngsee, J. K. Isolation and characterization of a dual prenylated Rab and VAMP2 receptor. J. Biol. Chem. 272: 26991-26998, 1997. [PubMed: 9341137] [Full Text: https://doi.org/10.1074/jbc.272.43.26991]
McNew, J. A., Parlati, F., Fukuda, R., Johnston, R. J., Paz, K., Paumet, F., Sollner, T. H., Rothman, J. E. Compartmental specificity of cellular membrane fusion encoded in SNARE proteins. Nature 407: 153-159, 2000. [PubMed: 11001046] [Full Text: https://doi.org/10.1038/35025000]
Pascual, O., Casper, K. B., Kubera, C., Zhang, J., Revilla-Sanchez, R., Sul, J.-Y., Takano, H., Moss, S. J., McCarthy, K., Haydon, P. G. Astrocytic purinergic signaling coordinates synaptic networks. Science 310: 113-116, 2005. [PubMed: 16210541] [Full Text: https://doi.org/10.1126/science.1116916]
Salpietro, V., Malintan, N. T., Llano-Rivas, I., Spaeth, C. G., Efthymiou, S., Strino, P., Vandrovcova, J., Cutrupi, M. C., Chimenz, R., David, E., Di Rosa, G., Marce-Grau, A., and 24 others. Mutations in the neuronal vesicular SNARE VAMP2 affect synaptic membrane fusion and impair human neurodevelopment. Am. J. Hum. Genet. 104: 721-730, 2019. [PubMed: 30929742] [Full Text: https://doi.org/10.1016/j.ajhg.2019.02.016]
Schoch, S., Deak, F., Konigstorfer, A., Mozhayeva, M., Sara, Y., Sudhof, T. C., Kavalali, E. T. SNARE function analyzed in synaptobrevin/VAMP knockout mice. Science 294: 1117-1122, 2001. [PubMed: 11691998] [Full Text: https://doi.org/10.1126/science.1064335]
Shi, L., Shen, Q.-T., Kiel, A., Wang, J., Wang, H.-W., Melia, T. J., Rothman, J. E., Pincet, F. SNARE proteins: one to fuse and three to keep the nascent fusion pore open. Science 335: 1355-1359, 2012. [PubMed: 22422984] [Full Text: https://doi.org/10.1126/science.1214984]
Stein, A., Weber, G., Wahl, M. C., Jahn, R. Helical extension of the neuronal SNARE complex into the membrane. Nature 460: 525-528, 2009. [PubMed: 19571812] [Full Text: https://doi.org/10.1038/nature08156]
Weber, T., Zemelman, B. V., McNew, J. A., Westermann, B., Gmachi, M., Parlati, F., Sollner, T. H., Rothman, J. E. SNAREpins: minimal machinery for membrane fusion. Cell 92: 759-772, 1998. [PubMed: 9529252] [Full Text: https://doi.org/10.1016/s0092-8674(00)81404-x]
Zoraqi, G. K., Paradisi, S., Falbo, V., Taruscio, D. Genomic organization and assignment of VAMP2 to 17p12 by FISH. Cytogenet. Cell Genet. 89: 199-203, 2000. [PubMed: 10965122] [Full Text: https://doi.org/10.1159/000015612]