Syntaxin-6 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the ''STX6''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

Interactions

STX6 has been shown to interact with SNAP23,

VAMP3 Vesicle-associated membrane protein 3 is a protein that in humans is encoded by the ''VAMP3'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein are the main components of a protein complex involved i ...

and

VAMP4 Vesicle-associated membrane protein 4 is a protein that in humans is encoded by the ''VAMP4'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein SNAP25 are the main components of a protein complex inv ...

N terminal protein domain

The

protein domain In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of ...

Syntaxin 6 N terminal protein domain is a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (

SNARE SNARE proteins – " SNAP REceptor" – are a large protein family consisting of at least 24 members in yeasts, more than 60 members in mammalian cells, and some numbers in plants. The primary role of SNARE proteins is to mediate vesicle f ...

) found in endosomal transport vesicles. It is part of the family, of target SNAREs (t-SNAREs). It is a vital aid to exporting and importing cell cargo through a process called cell trafficking. Its SNARE motif shows significant homology to both syntaxin 1a and S25C, indicating similarity through

evolutionary conservation In evolutionary biology, conserved sequences are identical or similar sequences in nucleic acids ( DNA and RNA) or proteins across species ( orthologous sequences), or within a genome ( paralogous sequences), or between donor and receptor taxa ...

. The structure of the syntaxin 6 N-terminal domain shows strong structural similarity with the N-terminal domains of syntaxin 1a, Sso1p, and Vam3p; despite a very low level of sequence similarity. SNARE functions essentially as a tether to hold the vesicle. The cytoplasmic regions of SNARE found on transport vesicles and target membranes interact, then a four-helix coiled coil forms. This links the cell membrane and vesicles together in such a way that it overcomes the energetic barrier to fusing two lipid bilayers. This is the way cell cargo is exchanged. This particular entry focuses on the N-terminal domain of Syntaxin 6.

Structure

Members of this entry, which are found in the

amino terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amin ...

of various SNARE proteins, adopt a structure consisting of an antiparallel three-helix bundle. Their exact function has not been determined, though it is known that they regulate the SNARE motif, as well as mediate various protein-protein interactions involved in membrane-transport.

Function

SNAREs play a vital role in the trafficking of cell cargo. The vesicles fuse to the cell membrane with the help of SNARE proteins. The SNARE motifs form a

four-helix bundle A helix bundle is a small protein fold composed of several alpha helices that are usually nearly parallel or antiparallel to each other. Three-helix bundles Three-helix bundles are among the smallest and fastest known cooperatively folding struct ...

that contributes to the fusion of two membranes. More specifically, the N-terminal domain binds to the SNARE motif, and this intramolecular interaction decreases the rate of association with the partner SNARE. However the N terminal domain's function still remains to fully elucidated.

References

External links