Synaptosomal-associated protein 23 (SNAP23)

The protein contains 211 amino acids for an estimated molecular weight of 23354 Da.

 

Essential component of the high affinity receptor for the general membrane fusion machinery and an important regulator of transport vesicle docking and fusion. (updated: March 4, 2015)

Protein identification was indicated in the following studies:

  1. Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
  2. Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
  3. Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
  4. 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.
  5. Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
  6. D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
  7. 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 annotated as membranous in UniProt.


Interpro domains
Total structural coverage: 44%
Model score: 49
MODL_I-TASSER-2.1
MODL_I-TASSER-2.1

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The reference OMIM entry for this protein is 602534

Synaptosomal-associated protein, 23-kd; snap23
Snap23a snap23b
Snap23c
Snap23d
Snap23e

DESCRIPTION

Synaptosomal-associated proteins (SNAPs), such as SNAP23, are involved in the process of membrane fusion in intracellular vesicle traffic (Ravichandran et al., 1996).

CLONING

Ravichandran et al. (1996) used syntaxin-4 (186591) as bait in expression cloning to isolate novel proteins involved in membrane fusion in other cell types. From a human B-cell lymphocyte library, they identified SNAP23, which shows homology to SNAP25 (600322). SNAP25 is part of a complex, termed 'SNARE,' that is responsible for membrane fusion in neurons. The SNAP23 cDNA encodes a 211-amino acid polypeptide with a predicted mass of 23 kD. Its amino acid sequence is 59% identical to that of SNAP25. Northern blot analysis revealed that SNAP23 is ubiquitously expressed. Mollinedo and Lazo (1997) used RT-PCR to identify an alternatively spliced variant of SNAP23 in human neutrophils. This isoform, termed SNAP23B, encodes a protein sequence of 158 amino acids with a deduced mass of 17.8 kD. Lazo et al. (2001) determined that SNAP23B lacks a region that is required for nonspecific binding to plasma membranes. Shukla et al. (2001) identified 3 additional splice variants that they designated SNAP23C, SNAP23D, and SNAP23E, all of which showed deletions in comparison with SNAP23A. With use of variant-specific primers in RT-PCR, they found mRNA for all 5 SNAP23 variants in human eosinophils, peripheral blood mononuclear cells, neutrophils, brain tissue, and basophilic and eosinophilic cell lines. Transfection of a basophilic cell line with reporter constructs for each of these variants revealed a plasma membrane localization for SNAPA and SNAPB, and both membrane and intracellular localization for SNAP23C, SNAPD, and SNAP23E.

GENE FUNCTION

Ravichandran et al. (1996) determined that SNAP23 is able to bind to multiple syntaxins as well as to multiple vesicle-associated membrane proteins (see 185880). Guo et al. (1998) reported that SNAP23 relocates in response to stimulation from plasma membrane lamellipodia-like projections to granule membranes in permeabilized mast cells. While relocation is a prerequisite for secretion, it can occur without membrane fusion and will expedite a subsequent secretory response. After relocation, SNAP23 is required for exocytosis, implying a crucial role in promoting membrane fusion. Thus, relocation of SNAP23 regulates compound exocytosis and links granule-plasma membrane and granule-granule fusions. Using immunofluorescence and immunoelectron microscopy, Galli et al. (1998) demonstrated that human TIVAMP (VAMP7; 300053), syntaxin-3 (STX3A; 600876), and SNAP23, were insensitive to proteolysis by numerous clostridial neurotoxins (NTs). TIVAMP-containing vesicles were concentrated in the apical domain of epithelial cells. STX3A and SNAP23 were codistributed at the apical plasma membrane, where they formed N-ethyl maleimide-dependent SNARE complexes with TIVAMP and cellubrevin (VAMP3; 603657). Galli et al. (1998) proposed that TIVAMP, STX3A, and SNAP23 participate in exocytotic processes at the apical plasma membrane of epithelial cells and in clostridial NT-resistant pathways. Using RT-PCR, immunoblot analysis, and immunofluorescence microscopy, Sander et al. (2008) demonstrated that human intestinal mast cells (MCs) expressed SNAP23, STX1B (601485), STX2 (132350), STX3, STX4 (STX4A; 186591), and STX6 (603944), but not SNAP25. MCs also expressed VAMP3, VAMP7, and VAMP8 (603177), but, in contrast with ro ... More on the omim web site

Subscribe to this protein entry history

Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated

Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated

March 16, 2016: Protein entry updated
Automatic update: OMIM entry 602534 was added.

Sept. 16, 2015: Protein entry updated
Automatic update: model status changed