Syntaxins ("syntaxin isotypes 1-4") are membrane integrated
Q-SNARE proteinsparticipating in exocytosis.
Syntaxins possess a single C-terminal transmembrane domain, a SNARE domain (known as H3), and an N-terminal regulatory domain (Habc).
* The SNARE (H3) domain binds to both
synaptobrevinand SNAP-25forming the core SNARE complex. Formation of this incredibly stable SNARE core complex is believed to generate the free energy required to initiate fusion between the vesicle membrane and plasma membrane.
* The N-terminal Habc domain is formed by 3 -helices and when collapsed onto its own H3 helix forms an inactive "closed" syntaxin conformation. This closed conformation of syntaxin is believed to be stabilized by binding of
nSec1(Munc18), although more recent data suggests that nSec1 may bind to other conformations of syntaxin, as well. The "open" syntaxin conformation is the conformation that is competent to form into SNARE core complexes.
synaptotagminin a calcium-dependent fashion and interact with voltage dependent calcium and potassium channels via the C-terminal H3 domain. Direct syntaxin-channel interaction is a suitable molecular mechanism for proximity between the fusion machinery and the gates of entry during depolarization of the presynaptic axonal boutons. Interestingly a N-terminal cleavage product of Syntaxin 3 (STX3) interacts very strong with RanBP5 and might act in nuclear signaling. The helices might play an important role in this aspect. (STX3 is the only syntaxin which contains a cleavage site)Recently published data show that alternative spliced Syntaxin 1 (STX1B) which lacks the transmembrane domain localizes in the nuclei (Nuclear localization of a novel human syntaxin 1B isoform. Pereira et al., Gene 2008) similar like STX3.
"In vitro" syntaxin per se is sufficient to drive spontaneous calcium independent fusion of
synaptic vesiclescontaining v-SNAREs.cite journal
author = Woodbury DJ, Rognlien K
url = http://pdbio.byu.edu/Faculty/djw82/Woodbury%20Rognlien%202000%20CBI%20color.pdf
title = The t-SNARE syntaxin is sufficient for spontaneous fusion of synaptic vesicles to planar membranes
journal = Cell Biology International
volume = 24
issue = 11
pages = 809–818
year = 2000
doi = 10.1006/cbir.2000.0631] More recent and somewhat controversial amperometric data suggest that the transmembrane domain of Syntaxin1A may form part of the fusion pore of exocytosis.cite journal
author = Han X, Wang CT, Bai J, Chapman ER, Jackson MB
url = http://www.physiology.wisc.edu/pubs/Han_et_al._Science_2004.pdf
title = Transmembrane Segments of Syntaxin Line the Fusion Pore of Ca2+-Triggered Exocytosis
journal = Science
volume = 304
pages = 289–292
year = 2004
doi = 10.1126/science.1095801
pmid = 15016962]
STX1A, STX1B, STX2, STX3, STX4, STX5, STX6, STX7, STX8, STX10, STX11, STX12, STX16, STX17, STX18, STX19
References and notes
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Syntaxin 3 — Syntaxin 3, also known as STX3, is a human gene.cite web | title = Entrez Gene: STX3 syntaxin 3| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=6809| accessdate = ] The protein encoded by this gene is a… … Wikipedia
Syntaxin — Syntaxine sind Proteine, die sich in Membranen integrieren und bei der Fusion von Membranen mitwirken. Ein Beispiel sind die SNARE Proteine, die bei der Vesikelfusion eine Rolle spielen. So interagiert Syntaxin 1 (t SNARE) mit SNAP 25 und… … Deutsch Wikipedia
syntaxin — (= t SNARE) Integral membrane protein of presynaptic membrane. Has a long cytoplasmic domain involved in the targeting of vesicles … Dictionary of molecular biology
syntaxin — noun Any of various proteins participating in exocytosis … Wiktionary
Syntaxin binding protein 2 — Syntaxin binding protein 2, also known as STXBP2, is a human gene.cite web | title = Entrez Gene: STXBP2 syntaxin binding protein 2| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=6813| accessdate = ] PBB… … Wikipedia
Syntaxin binding protein 3 — Syntaxin binding protein 3, also known as STXBP3, is a human gene.cite web | title = Entrez Gene: STXBP3 syntaxin binding protein 3| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=6814| accessdate = ] PBB… … Wikipedia
STX1A — Syntaxin 1A (brain) PDB rendering based on 1br0 … Wikipedia
STX7 — Syntaxin 7, also known as STX7, is a human gene.cite web | title = Entrez Gene: STX7 syntaxin 7| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=8417| accessdate = ] PBB Summary section title = summary text … Wikipedia
STX4 — Syntaxin 4, also known as STX4, is a human gene. [cite web | title = Entrez Gene: STX4 Syntaxin 4| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=6810| accessdate = ] PBB Summary section title = summary… … Wikipedia
STX8 — Syntaxin 8, also known as STX8, is a human gene.cite web | title = Entrez Gene: STX8 syntaxin 8| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=9482| accessdate = ] PBB Summary section title = summary text … Wikipedia