Syntaxin 4, Recombinant, Human, aa1-183 (NY-REN-31, p35-2, STX4)

Syntaxin 4 (STX4) is a widely expressed type IV transmembrane protein that is a member of the syntaxin family of t­SNARE (target­Soluble NSF [N­ethylmaleimide­sensitive factor] Attachment REceptor) membrane fusion proteins (1, 2). For membrane fusion, VAMPs (Vesicle­Associated Membrane Proteins, also called Synaptotagmins) as v­SNAREs on donor (vesicle) membranes interact with t­SNAREs and SNAPs (Soluble NSF Attachment Proteins) on target (cell surface) membranes, with SM (Sec1/Munc18­like) accessory proteins acting as catalysts for fusion (2). Human Syntaxin 4 cDNA encodes 297 amino acids (aa) including basolateral targeting motif for epithelial cells (aa24­29), a coiled­coil domain termed Habc (aa43­163), an S­nitrosylation site which regulates fusion (aa141), a hinge region, a t­SNARE domain (aa 200­262), and a C­terminal transmembrane domain (aa276­296) (1­4). Within aa1­183, human Syntaxin 4 shares 89% aa sequence homology with mouse and rat, and 94­95% with canine, bovine, equine, porcine, feline and ovine Syntaxin 4. Among its known roles, Syntaxin 4 and SNAP­23 or SNAP­25 associate with VAMP­2 for fusion of GLUT4­containing vesicles with the plasma membrane in muscle and adipose cells (1, 5). It is required for exocytosis of insulin from pancreatic beta­cells (3, 6, 7). With SNAP23 and VAMP­3, it allows endosome recycling to extend podosomes during macrophage migration (7­9). It establishes polarization of epithelial cells, specifying basolateral sorting of proteins (4, 10). It mediates postsynaptic activity­dependent exocytosis in neural cell dendritic spines (11). It is involved in exocytosis of ANP from cardiomyocytes (12). In FAS­mediated apoptosis, it allows translocation of acid sphingomyelinase to the cell surface (13). Syntaxin 4 binds F­actin and gelsolin, linking the plasma membrane with, or releasing it from, the actin cytoskeleton (6, 7). Source: Recombinant protein corresponding to aa1-183 from human Syntaxin 4, fused to 6-his tag at C-terminal, expressed in E. coli. Molecular Weight: ~23kD, Endotoxin: <0.01EU/1ug (LAL method), Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute in sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.