Vesicle-associated membrane protein 7 (VAMP7)

The protein contains 220 amino acids for an estimated molecular weight of 24935 Da.

 

Involved in the targeting and/or fusion of transport vesicles to their target membrane during transport of proteins from the early endosome to the lysosome. Required for heterotypic fusion of late endosomes with lysosomes and homotypic lysosomal fusion. Required for calcium regulated lysosomal exocytosis. Involved in the export of chylomicrons from the endoplasmic reticulum to the cis Golgi. Required for exocytosis of mediators during eosinophil and neutrophil degranulation, and target cell killing by natural killer cells. Required for focal exocytosis of late endocytic vesicles during phagosome formation. (updated: Oct. 10, 2018)

Protein identification was indicated in the following studies:

  1. Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
  2. Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
  3. D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
  4. Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.

Methods

The following articles were analysed to gather the proteome content of erythrocytes.

The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.

PublicationIdentification 1Uniprot mapping 2Not mapped /
Obsolete		TrEMBLSwiss-Prot
Goodman (2013)2289 (gene list)227853205992269
Lange (2014)123412347281224
Hegedus (2015)2638262202352387
Wilson (2016)165815281702911068
d'Alessandro (2017)18261817201815
Bryk (2017)20902060101081942
Chu (2018)18531804553621387

1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry

The compilation of older studies can be retrieved from the Red Blood Cell Collection database.

The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.

No sequence conservation computed yet.
Protein sequence (FASTA)
Protein coevolution profile (FreeContact)
Multiple Sequence Alignment (Muscle)

This protein is annotated as membranous in Gene Ontology, is predicted to be membranous by TOPCONS.

Topcons

Interpro domains
Total structural coverage: 89%
Model score: 0
No model available.

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The reference OMIM entry for this protein is 300053

Vesicle-associated membrane protein 7: vamp7
Synaptobrevin-like 1; sybl1
Tetanus neurotoxin-insensitive vamp; tivamp

DESCRIPTION

Exocytosis of vesicle contents requires fusion of opposing membrane layers, and the highly conserved proteins of the SNARE family are crucially involved in this process. SNAREs localized to the vesicle membrane, or v-SNAREs, include VAMP7, and SNAREs localized to the target membrane, or t-SNARES, include the SNAPs (see SNAP25; 600322) and the syntaxins (see STX1A; 186590). The SNARE proteins assemble into a core complex of bundled helices and thereby contribute to membrane fusion (summary by Sander et al., 2008).

CLONING

From a search for expressed genes in the Xq28 pseudoautosomal region (PAR), D'Esposito et al. (1996) identified a 2,576-bp cDNA encoding a synaptobrevin-like gene. The gene, designated SYBL1, encodes a 220-amino acid polypeptide of 25 kD with 60% similarity (37.5% homology) to an unpublished Arabidopsis gene sequence. SYBL1 was found, unlike all Xp pseudoautosomal genes studied to that time, to undergo X inactivation. In addition, it is also inactive on the Y chromosome, thereby maintaining dosage compensation in an unprecedented way. Using Northern blot analysis, Matarazzo et al. (1999) found that, like human SYBL1, mouse Sybl1 was ubiquitously expressed. By immunoblot and immunohistochemical analyses using antibodies against the cytoplasmic domain of VAMP7, Advani et al. (1999) detected expression of a 25-kD membrane-associated protein in multiple mammalian tissues and cell lines. VAMP7 colocalized with LAMP1 (153330), a marker of late endosomes and lysosomes. Immunoelectron microscopy revealed greatest concentration of VAMP7 in the trans-Golgi network. Advani et al. (1999) concluded that the data were consistent with a role for VAMP7 in vesicular transport of proteins from the early endosome to the lysosome.

GENE STRUCTURE

Matarazzo et al. (1999) determined that the human and mouse VAMP7 genes contain 8 exons.

MAPPING

D'Esposito et al. (1996) identified the SYBL1 gene within the second pseudoautosomal region (PAR2) on chromosome Xq28. The synaptobrevin genes SYB1 (185880) and SYB2 (185881) are autosomal, being located on chromosomes 12 and 17, respectively. In studies of the pseudoautosomal regions of the X and Y chromosomes, Ciccodicola et al. (2000) sequenced the telomeric 400 kb of the long arm of the human X chromosome, including 330 kb of the human Xq/Yq pseudoautosomal region and the telomere. Sequencing revealed subregions with distinctive regulatory and evolutionary features. The proximal 295 kb contains 2 genes inactivated on both the inactive X and Y chromosomes: SYBL1 and a human homolog of 'sprouty' in Drosophila (SPRY3; 300531). The GC-rich distal 35 kb, added in stages and much later in evolution, contains the X/Y expressed gene IL9R (300007) and the gene CXYorf1 only 5 kb from the Xq telomere. These properties make Xq/YqPAR a model for studies of region-specific gene inactivation, telomere evolution, and involvement in sex-limited conditions.

GENE FUNCTION

By investigating promoter DNA methylation profiles, Matarazzo et al. (2002) determined that chromatin on the repressed Xi and the Y alleles of SYBL1 has underacetylated histones H3 and H4 and H3-lysine 9 methylation. The SYBL1 alleles on the inactive X and Y chromosomes were also found to have a condensed chromatin conformation. In contrast, the expressed allele showed H3 and H4 acetylation, H3-lysine-4 methylation, and a less compacted chromatin conformation. In ICF syndrome (242860) ... More on the omim web site

Subscribe to this protein entry history

Oct. 20, 2018: Protein entry updated
Automatic update: OMIM entry 300053 was added.

Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).