| First Author | Sasaki T | Year | 2005 |
| Journal | J Biol Chem | Volume | 280 |
| Issue | 10 | Pages | 9308-12 |
| PubMed ID | 15615719 | Mgi Jnum | J:97771 |
| Mgi Id | MGI:3576396 | Doi | 10.1074/jbc.M413773200 |
| Citation | Sasaki T, et al. (2005) Direct inhibition of the interaction between alpha-interaction domain and beta-interaction domain of voltage-dependent Ca2+ channels by Gem. J Biol Chem 280(10):9308-12 |
| abstractText | The Ras-related small G-protein Gem regulates voltage-dependent Ca2+ channels (VDCCs) through interaction with the beta-subunit of the VDCC. This action of Gem is mediated by regulated alpha1-subunit expression at the plasma membrane. In the present study, we examined the mechanism of the inhibition of VDCC activity by Gem. The beta-interaction domain (BID) of the beta-subunit, which specifically interacts with the alpha-interaction domain (AID) of the alpha1-subunit, is shown to be essential for the interaction between Gem and beta-subunits. In addition, the AID peptide inhibited interaction between Gem and beta-subunits in a dose-dependent manner. GemS88N mutant, which has low binding affinity for guanine nucleotide, did not interact with beta-subunits, allowing alpha1-subunit expression at the plasma membrane. This inhibitory effect of wild-type Gem on VDCC activity was reduced in cells expressing GemS88N. The overexpression of wild-type Gem in pancreatic beta-cell line MIN6 cells suppressed Ca2+-triggered secretion, whereas overexpression of GemS88N induced Ca2+-triggered secretion to control level. These results suggest that GTPase activity of Gem is required for the binding of Gem to BID that regulates VDCC activity through interaction with AID. |
