TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
8.A.91.1.1









Syntaxin-related protein, Knolle or Syntaxin111, of 310 aas and 1 C-terminal TMS.  Acts as a cell plate-specific syntaxin, required for the fusion of vesicles at the plane of cell division. It is abundant in flowers and developing siliques but is present in low amounts in the seedlings, roots, and leaves. Localizes to the cell plate to mediate cytokinesis (Teh et al. 2013).It and other syntaxins bind Tomosyn to block secretion (Li et al. 2019).

Eukaryota
Viridiplantae
Knolle of Arabidopsis thaliana (Mouse-ear cress)
8.A.91.1.2









Syntaxin, Stx1b2-prov, of 290 aas and 1 C-terminal TMS.

 

Eukaryota
Metazoa
Stx1b2 of Xenopus laevis (African clawed frog)
8.A.91.1.3









Syntaxin 7L, Stx7, of 259 aas and 1 C-terminal TMS.

Eukaryota
Metazoa
Stx7 of Xenopus laevis (African clawed frog)
8.A.91.1.4









Syntaxin-1A (Stx1; Stx1A; Sx1) of 288 aas.  Co-localizes with L-type Ca2+-channels (Cav1.2) in nano clusters at the plasma membrane (Sajman et al. 2017). Munc18 bridges the few syntaxin molecules residing on granules to the syntaxin cluster on the plasma membrane, suggesting that the number of syntaxins on vesicles determines docking and possibly fusion probability  (Borisovska 2018). Munc18-1 (P61764; see 1.F.1.1.3)), a neuronal protein that interacts with syntaxin 1 and is required for synaptic vesicle exocytosis, depends on two Munc18-1-interacting proteins called Mint1 or APBA1 (TC# 8.A.24.2.2) and Mint2 or SAPBA2 (TC# 8.A.24.2.3) (Okamoto and Südhof 1997). Syntaxin 1A has a binding site in its H3 domain that is critical for targeting of the H+-ATPase to the apical membrane of renal epithelial cells (Li et al. 2005). The mechanisms regulating syntaxin-1 nanoclustering on the plasma membrane have been considered (Padmanabhan et al. 2019).

Eukaryota
Metazoa
Syntaxin 1A of Homo sapiens
8.A.91.1.5









Syntaxin homologue, Sso1 of 290 aas and 1 C-terminal TMS (Ghaemmaghami et al. 2003). Membrane fusion transits through hemifusion, a condition in which the outer leaflets of the bilayers are mixed, but the inner leaflets are not. Hemifusion then proceeds to the fusion pore that connects the two internal contents. The TMSs of the fusion proteins play an essential role in the transition from hemifusion to the fusion pore. Sso1p, a target membrane t-SNARE involved in the trafficking from Golgi to plasma membrane. The TMS of Sso1p is a well-defined membrane spanning α-helix. There is an equilibrium between the monomers and the oligomers, and oligomerization is mainly mediated through the interaction at the N-terminal half of the TMS, whereas the C-terminal half is free of the tertiary interaction (Zhang and Shin 2006).

Eukaryota
Fungi
Sso1 of Saccharomyces cerevisiae (Baker's yeast)
8.A.91.1.6









Syntaxin 3 (Stx3) of 289 aas with a C-terminal transmembrane anchor domain, is a  SNARE protein that is required for its membrane fusion activity.  Stx3 also functions as a nuclear regulator of gene expression. Alternative splicing creates a soluble isoform (Stx3S), lacking the transmembrane anchor which binds to the nuclear import factor RanBP5 (RAN-binding protein 5), targets to the nucleus, and interacts physically and functionally with several transcription factors (Giovannone et al. 2018). Mutations can cause microvillus inclusion disease (Julia et al. 2019).

Eukaryota
Metazoa
Stx3 of Homo sapiens
8.A.91.1.7









Syntaxin-121 of 346 aas and 1 C-terminal TMS. It is a vesicle trafficking protein that functions in the secretory pathway. It is a plasma membrane (PM)-resident syntaxin-like Q-SNARE, that interacts with QUIRKY (QKY; TC# 9.A.57.1.7), a member of the family of multiple C2 domain and transmembrane region proteins (MCTPs), to mediate FLOWERING LOCUS T transport (Liu et al. 2019).

 

Eukaryota
Viridiplantae
Syp121 of Arabidopsis thaliana (Mouse-ear cress)
8.A.91.1.8









Syntaxin-19, Stx19, of 294 aas.  S-acylation regulates the trafficking and stability of this unconventional Q-SNARE (Ampah et al. 2018).

Eukaryota
Metazoa
Stx19 of Homo sapiens
8.A.91.1.9









Syntaxin 5, Stx5, of 355 aas and one C-terminal TMS. It mediates ER to Golgi transport, and together with p115/USO1 and GM130/GOLGA2, is involved in vesicle tethering and fusion at the cis-Golgi membrane to maintain the stacked and inter-connected structure of the Golgi apparatus (Linders et al. 2019). Syntaxin 5 interacts with presenilin holoproteins and affects beta-amyloid peptide production (Suga et al. 2004).

 

Eukaryota
Metazoa
Stx5 of Homo sapiens
8.A.91.1.10









Syntaxin 5, Sed5, of 340 aas and 1 C-terminal TMS.  It is required for vesicular transport between the endoplasmic reticulum and the Golgi complex (Linders et al. 2019), and acts as an attachment protein receptor (Ghaemmaghami et al. 2003).

Eukaryota
Fungi
Sed5 of Saccharomyces cerevisiae
8.A.91.1.11









Syntaxin 17, Stx17, of 302 aas and 2 C-terminal TMSs. It is instrumental for engagement during autophagosome fusion with endolysosomes, and the process is regulated by kinase ULK1 and the apoptosis modulator BRUCE (Viret and Faure 2019). SNAREs localize on opposing membranes and assemble to form a trans-SNARE complex, an extended, parallel four alpha-helical bundle that drives membrane fusion (Cheng et al. 2017).

Eukaryota
Metazoa
Stx17 of Homo sapiens
8.A.91.1.12









Syntaxin 4, Stx4, of 297 aas and one C-terminal TMS. It is a plasma membrane t-SNARE that mediates docking of transport vesicles and is necessary for the translocation of SLC2A4 (glucose transporter; "Glut4, GTR4) from intracellular vesicles to the plasma membrane. Together with STXB3 and VAMP2, it may also play a role in docking/fusion of intracellular GLUT4-containing vesicles with the cell surface in adipocytes and may play a role in docking of synaptic vesicles at presynaptic active zones. Lipid domains assemble syntaxin 4 within themselves by selectively interacting with the transmembrane domain of Stx4. The localized syntaxin 4, in turn, facilitated the fusion of transport vesicles that contained the dopamine transporter with the domain of the plasma membrane, which led to the localized distribution of the transporter to that domain. A pivotal role of a  phospholipase A1, specifically PLRP2, is played in the formation of functional domains in the plasma membrane of neurons (Kuge et al. 2020).

 

Eukaryota
Opisthokonta
Stx4 of Homo sapiens