Synaptosomal-associated protein 23 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''SNAP23''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Two alternative transcript variants encoding different protein isoforms have been described for this gene.
Function
Specificity of vesicular transport is regulated, in part, by the interaction of a
vesicle-associated membrane protein termed
synaptobrevin/VAMP with a target compartment membrane protein termed
syntaxin
Syntaxins are a family of membrane integrated Q-SNARE proteins participating in exocytosis.
Domains
Syntaxins possess a single C-terminal transmembrane domain, a SNARE domain (known as H3), and an N-terminal regulatory domain (Habc).
Syntaxi ...
. These proteins, together with
SNAP25 (synaptosome-associated protein of 25 kDa), form a complex which serves as a binding site for the general membrane fusion machinery. Synaptobrevin/VAMP and syntaxin are believed to be involved in vesicular transport in most, if not all cells, while SNAP25 is present almost exclusively in the brain, suggesting that a ubiquitously expressed homolog of SNAP25 exists to facilitate transport vesicle/target membrane fusion in other tissues.
SNAP23 is structurally and functionally similar to SNAP25 and binds tightly to multiple syntaxins and synaptobrevins/VAMPs. It is an essential component of the high affinity receptor for the general membrane fusion machinery and is an important regulator of transport vesicle docking and fusion.
Clinical significance
In individuals with
insulin resistance, SNAP23 is found to be translocated from the plasma membrane to the cytosol where it becomes associated with lipid droplets and is therefore unable to translocate
GLUT-4 to the membrane, hindering glucose transport.
Interactions
SNAP23 has been shown to
interact with:
*
Cystic fibrosis transmembrane conductance regulator
Cystic fibrosis transmembrane conductance regulator (CFTR) is a membrane protein and anion channel in vertebrates that is encoded by the ''CFTR'' gene.
Geneticist Lap-Chee Tsui and his team identified the ''CFTR'' gene in 1989 as the gene lin ...
,
*
KIF5B,
*
NAPA,
*
SNAPAP,
*
STX11,
[
* STX2,]STX4
Syntaxin-4 is a protein that in humans is encoded by the ''STX4'' gene.
Interactions
STX4 has been shown to Protein-protein interaction, interact with:
* Gelsolin,
* NAPA (gene), NAPA,
* RAB4A,
* SNAP-25,
* SNAP23,
* STXBP1,
* STXBP5,
...
,[
* VAMP2,][ and
* Vesicle-associated membrane protein 8.][
]
References
Further reading
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
{{PDB Gallery, geneid=8773