Synaptosomal-associated protein 29 (SNAP29)
The protein contains 258 amino acids for an estimated molecular weight of 28970 Da.
SNAREs, soluble N-ethylmaleimide-sensitive factor-attachment protein receptors, are essential proteins for fusion of cellular membranes. SNAREs localized on opposing membranes assemble to form a trans-SNARE complex, an extended, parallel four alpha-helical bundle that drives membrane fusion. SNAP29 is a SNARE involved in autophagy through the direct control of autophagosome membrane fusion with the lysososome membrane. Plays also a role in ciliogenesis by regulating membrane fusions. (updated: Oct. 25, 2017)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- 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.
- 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.
- 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.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
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.
This protein is annotated as membranous in Gene Ontology, is annotated as membranous in UniProt.
(right-click above to access to more options from the contextual menu)
Biological Process
Autophagosome maturation
Autophagosome membrane docking
Cilium assembly
Exocytosis
Membrane fusion
Neutrophil degranulation
Protein transport
Synaptic vesicle fusion to presynaptic active zone membrane
Synaptic vesicle priming
Vesicle fusion
Vesicle targeting
The reference OMIM entry for this protein is 604202
Synaptosomal-associated protein, 29-kd; snap29
DESCRIPTION
Intracellular membrane traffic appears to be regulated in part by SNAREs, SNAP (soluble N-ethylmaleimide-sensitive factor-attachment protein; see SNAP-alpha, 603215) receptors, through the formation of complexes between SNAREs on vesicle and target membranes. In the nerve terminal, the core fusion complex is a parallel bundle of 4 helices formed from the coiled-coil domains of 3 proteins. Two helices are contributed by the SNAP25 (600322) plasma membrane protein, and 1 helix each comes from a vesicle SNARE, or VAMP, and a target membrane SNARE, or syntaxin. Dissociation of the core complex is mediated by recruitment of the NSF (601633) ATPase chaperone and SNAP-alpha to the complex, followed by ATP hydrolysis, thereby allowing the components to recycle for another round of membrane fusion (summary by Steegmaier et al., 1998).CLONING
By carrying out a yeast 2-hybrid screen with syntaxin-3 (600876) as bait, Steegmaier et al. (1998) isolated a partial cDNA encoding a protein with homology to SNAP25 and SNAP23 (602534). They used the partial cDNA to screen a brain library and recovered a cDNA corresponding to the complete coding sequence of the gene, which they called SNAP29 based on the predicted molecular weight of the encoded product. The deduced 258-amino acid SNAP29 protein is 17% identical to SNAP25 and SNAP23. Like SNAP23 and SNAP25, SNAP29 contains 2 predicted coiled-coil regions that can participate in the formation of the core complex. However, SNAP29 lacks the palmitoylated membrane-attachment domain found in the other 2 proteins and has a distinct localization pattern. Immunofluorescence studies of epitope-tagged SNAP29 indicated that it localized predominantly to intracellular membrane structures, whereas SNAP25 and SNAP23 are primarily localized to the plasma membrane. Northern blot analysis revealed that SNAP29 is expressed ubiquitously as a major 1.4-kb mRNA and 3 less abundant transcripts.MAPPING
Gross (2013) mapped the SNAP29 gene to chromosome 22q11.21 based on an alignment of the SNAP29 sequence (GenBank GENBANK AF115436) with the genomic sequence (GRCh37).GENE FUNCTION
Steegmaier et al. (1998) found that in vitro SNAP29 bound to a broader range of syntaxin fusion proteins than did SNAP25 or SNAP23. Steegmaier et al. (1998) proposed that SNAP29 is bound to membrane structures via its interaction with multiple syntaxins, and that it is capable of participating in various intracellular transport steps, interacting with different syntaxins and VAMPs specifically localized to distinct membrane compartments. Through several in vitro and in vivo binding assays, Hohenstein and Roche (2001) confirmed that SNAP29 binds to plasma membrane syntaxins as well as to syntaxins present on many different internal membranes. By coimmunoprecipitation studies, they also found that the association between syntaxin-6 and SNAP29 is enhanced in cells coexpressing VAMP. Rotem-Yehudar et al. (2001) found evidence for a role of SNAP29 in the endocytosis of IGF1 receptors (IGF1R; 147370). They found that EHD1 (605888) and SNAP29 interact directly with each other and are present in complexes with IGF1R. Following IGF1 induction, EHD1 and IGF1R colocalize intracellularly. Immunoprecipitation of rat tissues also suggested interaction of SNAP29 with AP2A1 (601026).MOLECULAR GENETICS
In affected patients with CEDNIK syndrome (609528), Sprecher et al. (2005) identified a homozygous mu ... More on the omim web site
Feb. 10, 2018: Protein entry updated
Automatic update: Entry updated from uniprot information.
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 604202 was added.
Feb. 25, 2016: Protein entry updated
Automatic update: model status changed
Feb. 24, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed