| First Author | Salaün C | Year | 2005 |
| Journal | J Biol Chem | Volume | 280 |
| Issue | 2 | Pages | 1236-40 |
| PubMed ID | 15542596 | Mgi Jnum | J:96186 |
| Mgi Id | MGI:3529652 | Doi | 10.1074/jbc.M410674200 |
| Citation | Salaun C, et al. (2005) The SNARE proteins SNAP-25 and SNAP-23 display different affinities for lipid rafts in PC12 cells. Regulation by distinct cysteine-rich domains. J Biol Chem 280(2):1236-40 |
| abstractText | SNAP-25 and its ubiquitously expressed homologue, SNAP-23, are SNARE proteins that are essential for regulated exocytosis in diverse cell types. Recent work has shown that SNAP-25 and SNAP-23 are partly localized in sphingolipid/cholesterol-rich lipid raft domains of the plasma membrane and that the integrity of these domains is important for exocytosis. Here, we show that raft localization is mediated by a 36-amino-acid region of SNAP-25 that is also the minimal sequence required for membrane targeting; this domain contains 4 closely spaced cysteine residues that are sites for palmitoylation. Analysis of endogenous levels of SNAP-25 and SNAP-23 present in lipid rafts in PC12 cells revealed that SNAP-23 (54% raft-associated) was almost 3-fold more enriched in rafts when compared with SNAP-25 (20% raft-associated). We report that the increased raft association of SNAP-23 occurs due to the substitution of a highly conserved phenylalanine residue present in SNAP-25 with a cysteine residue. Intriguingly, although the extra cysteine in SNAP-23 enhances its raft association, the phenylalanine at the same position in SNAP-25 acts to repress the raft association of this protein. These different raft-targeting signals within SNAP-25 and SNAP-23 are likely important for fine-tuning the exocytic pathways in which these proteins operate. |
