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Syntaxin binding protein 5 (tomosyn)
Protein STXBP5 PDB 1urq.png
PDB rendering based on 1urq.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols STXBP5 ; LGL3; LLGL3; Nbla04300
External IDs OMIM604586 MGI1926058 HomoloGene16402 GeneCards: STXBP5 Gene
Species Human Mouse
Entrez 134957 78808
Ensembl ENSG00000225135 ENSMUSG00000019790
UniProt Q5T5C0 Q8K400
RefSeq (mRNA) NM_001127715 NM_001081344
RefSeq (protein) NP_001121187 NP_001074813
Location (UCSC) Chr 6:
147.53 – 147.71 Mb
Chr 10:
9.76 – 9.9 Mb
PubMed search [1] [2]

Syntaxin-binding protein 5 is a protein that in humans is encoded by the STXBP5 gene.[1][2][3]

Syntaxin 1 is a component of the 7S and 20S SNARE complexes which are involved in docking and fusion of synaptic vesicles with the presynaptic plasma membrane. This gene encodes a syntaxin 1 binding protein. In rat, a similar protein dissociates syntaxin 1 from the Munc18/n-Sec1/rbSec1 complex to form a 10S complex, an intermediate which can be converted to the 7S SNARE complex. Thus this protein is thought to be involved in neurotransmitter release by stimulating SNARE complex formation. Alternatively spliced variants have been identified, but their biological validity has not been determined.[3]


STXBP5 has been shown to interact with STX4[4] and STX1A.[1][4]


  1. ^ a b Fujita Y, Shirataki H, Sakisaka T, Asakura T, Ohya T, Kotani H, Yokoyama S, Nishioka H, Matsuura Y, Mizoguchi A, Scheller RH, Takai Y (Jun 1998). "Tomosyn: a syntaxin-1-binding protein that forms a novel complex in the neurotransmitter release process". Neuron 20 (5): 905–15. doi:10.1016/S0896-6273(00)80472-9. PMID 9620695. 
  2. ^ Katoh M, Katoh M (Feb 2004). "Identification and characterization of human LLGL4 gene and mouse Llgl4 gene in silico". Int J Oncol 24 (3): 737–42. doi:10.3892/ijo.24.3.737. PMID 14767561. 
  3. ^ a b "Entrez Gene: STXBP5 syntaxin binding protein 5 (tomosyn)". 
  4. ^ a b Widberg, Charlotte H; Bryant Nia J; Girotti Milena; Rea Shane; James David E (Sep 2003). "Tomosyn interacts with the t-SNAREs syntaxin4 and SNAP23 and plays a role in insulin-stimulated GLUT4 translocation". J. Biol. Chem. (United States) 278 (37): 35093–101. doi:10.1074/jbc.M304261200. ISSN 0021-9258. PMID 12832401. 

Further reading[edit]