| First Author | Widberg CH | Year | 2003 |
| Journal | J Biol Chem | Volume | 278 |
| Issue | 37 | Pages | 35093-101 |
| PubMed ID | 12832401 | Mgi Jnum | J:91698 |
| Mgi Id | MGI:3050225 | Doi | 10.1074/jbc.M304261200 |
| Citation | Widberg CH, et al. (2003) Tomosyn interacts with the t-SNAREs syntaxin4 and SNAP23 and plays a role in insulin-stimulated GLUT4 translocation. J Biol Chem 278(37):35093-101 |
| abstractText | The Sec1p-like/Munc18 (SM) protein Munc18a binds to the neuronal t-SNARE Syntaxin1A and inhibits SNARE complex assembly. Tomosyn, a cytosolic Syntaxin1A-binding protein, is thought to regulate the interaction between Syntaxin1A and Munc18a, thus acting as a positive regulator of SNARE assembly. In the present study we have investigated the interaction between b-Tomosyn and the adipocyte SNARE complex involving Syntaxin4/SNAP23/VAMP-2 and the SM protein Munc18c, in vitro, and the potential involvement of Tomosyn in regulating the translocation of GLUT4 containing vesicles, in vivo. Tomosyn formed a high affinity ternary complex with Syntaxin4 and SNAP23 that was competitively inhibited by VAMP-2. Using a yeast two-hybrid assay we demonstrate that the VAMP-2-like domain in Tomosyn facilitates the interaction with Syntaxin4. Overexpression of Tomosyn in 3T3-L1 adipocytes inhibited the translocation of green fluorescent protein-GLUT4 to the plasma membrane. The SM protein Munc18c was shown to interact with the Syntaxin4 monomer, Syntaxin4 containing SNARE complexes, and the Syntaxin4/Tomosyn complex. These data suggest that Tomosyn and Munc18c operate at a similar stage of the Syntaxin4 SNARE assembly cycle, which likely primes Syntaxin4 for entry into the ternary SNARE complex. |
