| First Author | Yamazaki H | Year | 2010 |
| Journal | J Biol Chem | Volume | 285 |
| Issue | 46 | Pages | 36081-91 |
| PubMed ID | 20813840 | Mgi Jnum | J:170219 |
| Mgi Id | MGI:4944154 | Doi | 10.1074/jbc.M110.140129 |
| Citation | Yamazaki H, et al. (2010) Tyr-167/Trp-168 in type 1/3 inositol 1,4,5-trisphosphate receptor mediates functional coupling between ligand binding and channel opening. J Biol Chem 285(46):36081-91 |
| abstractText | The N-terminal approximately 220-amino acid region of the inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R)/Ca(2+) release channel has been referred to as the suppressor/coupling domain because it is required for both IP(3) binding suppression and IP(3)-induced channel gating. Measurements of IP(3)-induced Ca(2+) fluxes of mutagenized mouse type 1 IP(3)R (IP(3)R1) showed that the residues responsible for IP(3) binding suppression in this domain were not essential for channel opening. On the other hand, a single amino acid substitution of Tyr-167 to alanine completely impaired IP(3)-induced Ca(2+) release without reducing the IP(3) binding activity. The corresponding residue in type 3 IP(3)R (IP(3)R3), Trp-168, was also critical for channel opening. Limited trypsin digestion experiments showed that the trypsin sensitivities of the C-terminal gatekeeper domain differed markedly between the wild-type channel and the Tyr-167 mutant under the optimal conditions for channel opening. These results strongly suggest that the Tyr/Trp residue (Tyr-167 in IP(3)R1 and Trp-168 in IP(3)R3) is critical for the functional coupling between IP(3) binding and channel gating by maintaining the structural integrity of the C-terminal gatekeeper domain at least under activation gating. |
