Skip to main content
. Author manuscript; available in PMC: 2019 Jan 16.
Published in final edited form as: Nat Struct Mol Biol. 2018 Jul 16;25(8):660–668. doi: 10.1038/s41594-018-0089-6

Figure 7. Model for IP3R regulation by IP3 and Ca2+.

Figure 7

In the absence of Ca2+ and IP3, IP3R adopts a closed state. In the presence of IP3, IP3R adopts one of an ensemble of pre-activated states that are in equilibrium. In the presence of high Ca2+, the BTF ring is dissociated and the channel adopts an inhibited state. In the presence of high Ca2+ and IP3, the BTF ring is dissociated and the channel adopts an inhibited state. In the presence of low Ca2+ and IP3, the channel adopts a hypothetical activated state in which the S6 gate is opened.